[v3,2/2] gdb: Add nanoMIPS port

Message ID 20221121110603.124056-2-aleksandar.rikalo@syrmia.com
State New
Headers
Series [v3,1/2] sim: Add nanoMIPS port |

Commit Message

Aleksandar Rikalo Nov. 21, 2022, 11:06 a.m. UTC
  Co-Authored-By: Jaydeep Patil <jaydeep.patil@imgtec.com>
Co-Authored-By: Matthew Fortune <matthew.fortune@imgtec.com>
Co-Authored-By: Maciej W. Rozycki <macro@mips.com>
Co-Authored-By: Stefan Markovic <stefan.markovic@mips.com>
Co-Authored-By: Sara Graovac <sara.graovac@syrmia.com>
Co-Authored-By: Dragan Mladjenovic <dragan.mladjenovic@syrmia.com>
---
 config.sub                                    |    1 +
 configure                                     |    3 +
 configure.ac                                  |    3 +
 gdb/Makefile.in                               |    2 +
 gdb/NEWS                                      |    1 +
 gdb/configure.host                            |    1 +
 gdb/configure.tgt                             |   11 +
 gdb/features/Makefile                         |    4 +
 gdb/features/nanomips-cp0.xml                 |   13 +
 gdb/features/nanomips-cpu.xml                 |   44 +
 gdb/features/nanomips-dsp.xml                 |   20 +
 gdb/features/nanomips-fpu.xml                 |   45 +
 gdb/features/nanomips.c                       |   54 +
 gdb/features/nanomips.xml                     |   12 +
 gdb/features/nanomips64-cp0.xml               |   13 +
 gdb/features/nanomips64-cpu.xml               |   44 +
 gdb/features/nanomips64-dsp.xml               |   20 +
 gdb/nanomips-tdep.c                           | 3407 +++++++++++++++++
 gdb/nanomips-tdep.h                           |  144 +
 gdb/testsuite/gdb.asm/asm-source.exp          |    9 +-
 gdb/testsuite/gdb.asm/nanomips.inc            |   49 +
 .../gdb.base/catch-gdb-caused-signals.c       |    3 +
 gdb/testsuite/gdb.base/float.exp              |    2 +-
 gdb/testsuite/gdb.trace/trace-common.h        |    2 +-
 gdb/testsuite/lib/gdb.exp                     |    1 +
 25 files changed, 3905 insertions(+), 3 deletions(-)
 create mode 100644 gdb/features/nanomips-cp0.xml
 create mode 100644 gdb/features/nanomips-cpu.xml
 create mode 100644 gdb/features/nanomips-dsp.xml
 create mode 100644 gdb/features/nanomips-fpu.xml
 create mode 100644 gdb/features/nanomips.c
 create mode 100644 gdb/features/nanomips.xml
 create mode 100644 gdb/features/nanomips64-cp0.xml
 create mode 100644 gdb/features/nanomips64-cpu.xml
 create mode 100644 gdb/features/nanomips64-dsp.xml
 create mode 100644 gdb/nanomips-tdep.c
 create mode 100644 gdb/nanomips-tdep.h
 create mode 100644 gdb/testsuite/gdb.asm/nanomips.inc
  

Comments

Mike Frysinger Dec. 12, 2022, 9:42 a.m. UTC | #1
On 21 Nov 2022 12:06, Aleksandar Rikalo wrote:
>  config.sub                                    |    1 +
>  configure                                     |    3 +
>  configure.ac                                  |    3 +

changes to these files should be landed separately, and usually are sent to
the binutils list.  config.{guess,sub} updates are taken from gcc, and they
in turn take them from the gnuconfig project.  so if you can point to those
projects merging things, we sync on our side without question.  we do not
fork these files though.
-mike
  
Mike Frysinger Dec. 12, 2022, 9:45 a.m. UTC | #2
On 21 Nov 2022 12:06, Aleksandar Rikalo wrote:
> --- a/gdb/configure.tgt
> +++ b/gdb/configure.tgt
> @@ -448,6 +448,16 @@ msp430-*-elf*)
>  	gdb_target_obs="msp430-tdep.o"
>  	;;
>  
> +mt-*-*)
> +	# Target: Morpho Technologies ms1 processor
> +	gdb_target_obs="mt-tdep.o"
> +	;;

this patch is about nanomips, not this thing

> --- /dev/null
> +++ b/gdb/nanomips-tdep.c

this file seems to duplicate a lot of existing mips-tdep.c logic.
can't they be merged/kept in sync better ?
-mike
  

Patch

diff --git a/config.sub b/config.sub
index dba16e84c77..b562e37aa09 100755
--- a/config.sub
+++ b/config.sub
@@ -1243,6 +1243,7 @@  case $cpu-$vendor in
 			| moxie \
 			| mt \
 			| msp430 \
+			| nanomips | nanomipseb \
 			| nds32 | nds32le | nds32be \
 			| nfp \
 			| nios | nios2 | nios2eb | nios2el \
diff --git a/configure b/configure
index 80b2b02fe7e..626fe6de084 100755
--- a/configure
+++ b/configure
@@ -4064,6 +4064,9 @@  case "${target}" in
   mips*-*-*)
     noconfigdirs="$noconfigdirs gprof"
     ;;
+  nanomips*-*-elf*)
+    noconfigdirs="$noconfigdirs gas binutils ld gprof"
+    ;;
   nvptx*-*-*)
     noconfigdirs="$noconfigdirs target-libssp target-libstdc++-v3 target-libobjc"
     ;;
diff --git a/configure.ac b/configure.ac
index 36267d85785..352ff79fce7 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1297,6 +1297,9 @@  case "${target}" in
   mips*-*-*)
     noconfigdirs="$noconfigdirs gprof"
     ;;
+  nanomips*-*-elf*)
+    noconfigdirs="$noconfigdirs gas binutils ld gprof"
+    ;;
   nvptx*-*-*)
     noconfigdirs="$noconfigdirs target-libssp target-libstdc++-v3 target-libobjc"
     ;;
diff --git a/gdb/Makefile.in b/gdb/Makefile.in
index fb4d42c7baa..3ef458477f9 100644
--- a/gdb/Makefile.in
+++ b/gdb/Makefile.in
@@ -824,6 +824,7 @@  ALL_TARGET_OBS = \
 	mn10300-tdep.o \
 	moxie-tdep.o \
 	msp430-tdep.o \
+	nanomips-tdep.o \
 	netbsd-tdep.o \
 	nds32-tdep.o \
 	nios2-linux-tdep.o \
@@ -1394,6 +1395,7 @@  HFILES_NO_SRCDIR = \
 	mips-tdep.h \
 	mn10300-tdep.h \
 	moxie-tdep.h \
+	nanomips-tdep.h \
 	netbsd-nat.h \
 	netbsd-tdep.h \
 	nds32-tdep.h \
diff --git a/gdb/NEWS b/gdb/NEWS
index dddef6525de..57f74da652d 100644
--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -480,6 +480,7 @@  winheight
 
 * New targets
 
+GNU/ELF/nanoMIPS      nanomips*-*-*
 GNU/Linux/LoongArch		loongarch*-*-linux*
 
 * Removed targets
diff --git a/gdb/configure.host b/gdb/configure.host
index da71675b201..3a9799ee56e 100644
--- a/gdb/configure.host
+++ b/gdb/configure.host
@@ -61,6 +61,7 @@  i[34567]86*)		gdb_host_cpu=i386 ;;
 loongarch*)		gdb_host_cpu=loongarch ;;
 m68*)			gdb_host_cpu=m68k ;;
 mips*)			gdb_host_cpu=mips ;;
+nanomips*)		gdb_host_cpu=nanomips ;;
 powerpc* | rs6000)	gdb_host_cpu=powerpc ;;
 sparcv9 | sparc64)	gdb_host_cpu=sparc ;;
 s390*)			gdb_host_cpu=s390 ;;
diff --git a/gdb/configure.tgt b/gdb/configure.tgt
index e84e222ba0d..f4dba706a9c 100644
--- a/gdb/configure.tgt
+++ b/gdb/configure.tgt
@@ -448,6 +448,16 @@  msp430-*-elf*)
 	gdb_target_obs="msp430-tdep.o"
 	;;
 
+mt-*-*)
+	# Target: Morpho Technologies ms1 processor
+	gdb_target_obs="mt-tdep.o"
+	;;
+
+nanomips*-*-*)
+	# Target: nanomips ELF
+	gdb_target_obs="nanomips-tdep.o"
+	;;
+
 nds32*-*-elf)
 	# Target: AndesTech NDS32 core
 	gdb_target_obs="nds32-tdep.o"
@@ -766,6 +776,7 @@  m32r-*-*)		gdb_sim=m32r ;;
 m68hc11-*-*|m6811-*-*)	gdb_sim=m68hc11 ;;
 microblaze*-*-*)	gdb_sim=microblaze ;;
 mips*-*-*)		gdb_sim=mips ;;
+nanomips*-*-*)	gdb_sim=mips ;;
 mn10300*-*-*)		gdb_sim=mn10300 ;;
 moxie-*-*)		gdb_sim=moxie ;;
 msp430*-*-*)		gdb_sim=msp430 ;;
diff --git a/gdb/features/Makefile b/gdb/features/Makefile
index c3e07809db3..f89823a3f31 100644
--- a/gdb/features/Makefile
+++ b/gdb/features/Makefile
@@ -46,6 +46,7 @@ 
 # List of .dat files to create in ../regformats/
 WHICH = mips-linux mips-dsp-linux \
 	mips64-linux mips64-dsp-linux \
+	nanomips \
 	nios2-linux \
 	or1k-linux \
 	rs6000/powerpc-32 \
@@ -73,6 +74,8 @@  mips-expedite = r29,pc
 mips-dsp-expedite = r29,pc
 mips64-expedite = r29,pc
 mips64-dsp-expedite = r29,pc
+microblaze-expedite = r1,rpc
+nanomips-expedite = r29,pc
 nios2-linux-expedite = sp,pc
 or1k-expedite = r1,npc
 powerpc-expedite = r1,pc
@@ -106,6 +109,7 @@  XMLTOC = \
 	mips-linux.xml \
 	mips64-dsp-linux.xml \
 	mips64-linux.xml \
+	nanomips.xml \
 	nds32.xml \
 	nios2.xml \
 	or1k.xml \
diff --git a/gdb/features/nanomips-cp0.xml b/gdb/features/nanomips-cp0.xml
new file mode 100644
index 00000000000..7a3995f0fd7
--- /dev/null
+++ b/gdb/features/nanomips-cp0.xml
@@ -0,0 +1,13 @@ 
+<?xml version="1.0"?>
+<!-- Copyright (C) 2018-2022 Free Software Foundation, Inc.
+
+     Copying and distribution of this file, with or without modification,
+     are permitted in any medium without royalty provided the copyright
+     notice and this notice are preserved.  -->
+
+<!DOCTYPE feature SYSTEM "gdb-target.dtd">
+<feature name="org.gnu.gdb.nanomips.cp0">
+  <reg name="status" bitsize="32"/>
+  <reg name="badvaddr" bitsize="32"/>
+  <reg name="cause" bitsize="32"/>
+</feature>
diff --git a/gdb/features/nanomips-cpu.xml b/gdb/features/nanomips-cpu.xml
new file mode 100644
index 00000000000..bb04a24d6f6
--- /dev/null
+++ b/gdb/features/nanomips-cpu.xml
@@ -0,0 +1,44 @@ 
+<?xml version="1.0"?>
+<!-- Copyright (C) 2018-2022 Free Software Foundation, Inc.
+
+     Copying and distribution of this file, with or without modification,
+     are permitted in any medium without royalty provided the copyright
+     notice and this notice are preserved.  -->
+
+<!DOCTYPE feature SYSTEM "gdb-target.dtd">
+<feature name="org.gnu.gdb.nanomips.cpu">
+  <reg name="r0" bitsize="32"/>
+  <reg name="r1" bitsize="32"/>
+  <reg name="r2" bitsize="32"/>
+  <reg name="r3" bitsize="32"/>
+  <reg name="r4" bitsize="32"/>
+  <reg name="r5" bitsize="32"/>
+  <reg name="r6" bitsize="32"/>
+  <reg name="r7" bitsize="32"/>
+  <reg name="r8" bitsize="32"/>
+  <reg name="r9" bitsize="32"/>
+  <reg name="r10" bitsize="32"/>
+  <reg name="r11" bitsize="32"/>
+  <reg name="r12" bitsize="32"/>
+  <reg name="r13" bitsize="32"/>
+  <reg name="r14" bitsize="32"/>
+  <reg name="r15" bitsize="32"/>
+  <reg name="r16" bitsize="32"/>
+  <reg name="r17" bitsize="32"/>
+  <reg name="r18" bitsize="32"/>
+  <reg name="r19" bitsize="32"/>
+  <reg name="r20" bitsize="32"/>
+  <reg name="r21" bitsize="32"/>
+  <reg name="r22" bitsize="32"/>
+  <reg name="r23" bitsize="32"/>
+  <reg name="r24" bitsize="32"/>
+  <reg name="r25" bitsize="32"/>
+  <reg name="r26" bitsize="32"/>
+  <reg name="r27" bitsize="32"/>
+  <reg name="r28" bitsize="32"/>
+  <reg name="r29" bitsize="32"/>
+  <reg name="r30" bitsize="32"/>
+  <reg name="r31" bitsize="32"/>
+
+  <reg name="pc" bitsize="32"/>
+</feature>
diff --git a/gdb/features/nanomips-dsp.xml b/gdb/features/nanomips-dsp.xml
new file mode 100644
index 00000000000..659fc3850c2
--- /dev/null
+++ b/gdb/features/nanomips-dsp.xml
@@ -0,0 +1,20 @@ 
+<?xml version="1.0"?>
+<!-- Copyright (C) 2018-2022 Free Software Foundation, Inc.
+
+     Copying and distribution of this file, with or without modification,
+     are permitted in any medium without royalty provided the copyright
+     notice and this notice are preserved.  -->
+
+<!DOCTYPE feature SYSTEM "gdb-target.dtd">
+<feature name="org.gnu.gdb.nanomips.dsp">
+  <reg name="hi0" bitsize="32"/>
+  <reg name="lo0" bitsize="32"/>
+  <reg name="hi1" bitsize="32"/>
+  <reg name="lo1" bitsize="32"/>
+  <reg name="hi2" bitsize="32"/>
+  <reg name="lo2" bitsize="32"/>
+  <reg name="hi3" bitsize="32"/>
+  <reg name="lo3" bitsize="32"/>
+
+  <reg name="dspctl" bitsize="32"/>
+</feature>
diff --git a/gdb/features/nanomips-fpu.xml b/gdb/features/nanomips-fpu.xml
new file mode 100644
index 00000000000..cac1d51f2ac
--- /dev/null
+++ b/gdb/features/nanomips-fpu.xml
@@ -0,0 +1,45 @@ 
+<?xml version="1.0"?>
+<!-- Copyright (C) 2018-2022 Free Software Foundation, Inc.
+
+     Copying and distribution of this file, with or without modification,
+     are permitted in any medium without royalty provided the copyright
+     notice and this notice are preserved.  -->
+
+<!DOCTYPE feature SYSTEM "gdb-target.dtd">
+<feature name="org.gnu.gdb.nanomips.fpu">
+  <reg name="f0" bitsize="64" type="ieee_double"/>
+  <reg name="f1" bitsize="64" type="ieee_double"/>
+  <reg name="f2" bitsize="64" type="ieee_double"/>
+  <reg name="f3" bitsize="64" type="ieee_double"/>
+  <reg name="f4" bitsize="64" type="ieee_double"/>
+  <reg name="f5" bitsize="64" type="ieee_double"/>
+  <reg name="f6" bitsize="64" type="ieee_double"/>
+  <reg name="f7" bitsize="64" type="ieee_double"/>
+  <reg name="f8" bitsize="64" type="ieee_double"/>
+  <reg name="f9" bitsize="64" type="ieee_double"/>
+  <reg name="f10" bitsize="64" type="ieee_double"/>
+  <reg name="f11" bitsize="64" type="ieee_double"/>
+  <reg name="f12" bitsize="64" type="ieee_double"/>
+  <reg name="f13" bitsize="64" type="ieee_double"/>
+  <reg name="f14" bitsize="64" type="ieee_double"/>
+  <reg name="f15" bitsize="64" type="ieee_double"/>
+  <reg name="f16" bitsize="64" type="ieee_double"/>
+  <reg name="f17" bitsize="64" type="ieee_double"/>
+  <reg name="f18" bitsize="64" type="ieee_double"/>
+  <reg name="f19" bitsize="64" type="ieee_double"/>
+  <reg name="f20" bitsize="64" type="ieee_double"/>
+  <reg name="f21" bitsize="64" type="ieee_double"/>
+  <reg name="f22" bitsize="64" type="ieee_double"/>
+  <reg name="f23" bitsize="64" type="ieee_double"/>
+  <reg name="f24" bitsize="64" type="ieee_double"/>
+  <reg name="f25" bitsize="64" type="ieee_double"/>
+  <reg name="f26" bitsize="64" type="ieee_double"/>
+  <reg name="f27" bitsize="64" type="ieee_double"/>
+  <reg name="f28" bitsize="64" type="ieee_double"/>
+  <reg name="f29" bitsize="64" type="ieee_double"/>
+  <reg name="f30" bitsize="64" type="ieee_double"/>
+  <reg name="f31" bitsize="64" type="ieee_double"/>
+
+  <reg name="fcsr" bitsize="32" group="float"/>
+  <reg name="fir" bitsize="32" group="float"/>
+</feature>
diff --git a/gdb/features/nanomips.c b/gdb/features/nanomips.c
new file mode 100644
index 00000000000..43cdc8a95d5
--- /dev/null
+++ b/gdb/features/nanomips.c
@@ -0,0 +1,54 @@ 
+/* THIS FILE IS GENERATED.  -*- buffer-read-only: t -*- vi:set ro:
+  Original: nanomips.xml */
+
+#include "defs.h"
+#include "osabi.h"
+#include "target-descriptions.h"
+
+struct target_desc *tdesc_nanomips;
+static void
+initialize_tdesc_nanomips (void)
+{
+  struct target_desc *result;
+  result = allocate_target_description ().release();
+  struct tdesc_feature *feature;
+
+  set_tdesc_architecture (result, bfd_scan_arch ("nanomips"));
+
+  feature = tdesc_create_feature (result, "org.gnu.gdb.nanomips.cpu");
+  tdesc_create_reg (feature, "r0", 0, 1, NULL, 32, "int");
+  tdesc_create_reg (feature, "r1", 1, 1, NULL, 32, "int");
+  tdesc_create_reg (feature, "r2", 2, 1, NULL, 32, "int");
+  tdesc_create_reg (feature, "r3", 3, 1, NULL, 32, "int");
+  tdesc_create_reg (feature, "r4", 4, 1, NULL, 32, "int");
+  tdesc_create_reg (feature, "r5", 5, 1, NULL, 32, "int");
+  tdesc_create_reg (feature, "r6", 6, 1, NULL, 32, "int");
+  tdesc_create_reg (feature, "r7", 7, 1, NULL, 32, "int");
+  tdesc_create_reg (feature, "r8", 8, 1, NULL, 32, "int");
+  tdesc_create_reg (feature, "r9", 9, 1, NULL, 32, "int");
+  tdesc_create_reg (feature, "r10", 10, 1, NULL, 32, "int");
+  tdesc_create_reg (feature, "r11", 11, 1, NULL, 32, "int");
+  tdesc_create_reg (feature, "r12", 12, 1, NULL, 32, "int");
+  tdesc_create_reg (feature, "r13", 13, 1, NULL, 32, "int");
+  tdesc_create_reg (feature, "r14", 14, 1, NULL, 32, "int");
+  tdesc_create_reg (feature, "r15", 15, 1, NULL, 32, "int");
+  tdesc_create_reg (feature, "r16", 16, 1, NULL, 32, "int");
+  tdesc_create_reg (feature, "r17", 17, 1, NULL, 32, "int");
+  tdesc_create_reg (feature, "r18", 18, 1, NULL, 32, "int");
+  tdesc_create_reg (feature, "r19", 19, 1, NULL, 32, "int");
+  tdesc_create_reg (feature, "r20", 20, 1, NULL, 32, "int");
+  tdesc_create_reg (feature, "r21", 21, 1, NULL, 32, "int");
+  tdesc_create_reg (feature, "r22", 22, 1, NULL, 32, "int");
+  tdesc_create_reg (feature, "r23", 23, 1, NULL, 32, "int");
+  tdesc_create_reg (feature, "r24", 24, 1, NULL, 32, "int");
+  tdesc_create_reg (feature, "r25", 25, 1, NULL, 32, "int");
+  tdesc_create_reg (feature, "r26", 26, 1, NULL, 32, "int");
+  tdesc_create_reg (feature, "r27", 27, 1, NULL, 32, "int");
+  tdesc_create_reg (feature, "r28", 28, 1, NULL, 32, "int");
+  tdesc_create_reg (feature, "r29", 29, 1, NULL, 32, "int");
+  tdesc_create_reg (feature, "r30", 30, 1, NULL, 32, "int");
+  tdesc_create_reg (feature, "r31", 31, 1, NULL, 32, "int");
+  tdesc_create_reg (feature, "pc", 32, 1, NULL, 32, "int");
+
+  tdesc_nanomips = result;
+}
diff --git a/gdb/features/nanomips.xml b/gdb/features/nanomips.xml
new file mode 100644
index 00000000000..ae05a91e935
--- /dev/null
+++ b/gdb/features/nanomips.xml
@@ -0,0 +1,12 @@ 
+<?xml version="1.0"?>
+<!-- Copyright (C) 2018-2022 Free Software Foundation, Inc.
+
+     Copying and distribution of this file, with or without modification,
+     are permitted in any medium without royalty provided the copyright
+     notice and this notice are preserved.  -->
+
+<!DOCTYPE target SYSTEM "gdb-target.dtd">
+<target>
+  <architecture>nanomips</architecture>
+  <xi:include href="nanomips-cpu.xml"/>
+</target>
diff --git a/gdb/features/nanomips64-cp0.xml b/gdb/features/nanomips64-cp0.xml
new file mode 100644
index 00000000000..6af2e2c369d
--- /dev/null
+++ b/gdb/features/nanomips64-cp0.xml
@@ -0,0 +1,13 @@ 
+<?xml version="1.0"?>
+<!-- Copyright (C) 2018-2022 Free Software Foundation, Inc.
+
+     Copying and distribution of this file, with or without modification,
+     are permitted in any medium without royalty provided the copyright
+     notice and this notice are preserved.  -->
+
+<!DOCTYPE feature SYSTEM "gdb-target.dtd">
+<feature name="org.gnu.gdb.nanomips.cp0">
+  <reg name="status" bitsize="32"/>
+  <reg name="badvaddr" bitsize="64"/>
+  <reg name="cause" bitsize="32"/>
+</feature>
diff --git a/gdb/features/nanomips64-cpu.xml b/gdb/features/nanomips64-cpu.xml
new file mode 100644
index 00000000000..30a237050a6
--- /dev/null
+++ b/gdb/features/nanomips64-cpu.xml
@@ -0,0 +1,44 @@ 
+<?xml version="1.0"?>
+<!-- Copyright (C) 2018-2022 Free Software Foundation, Inc.
+
+     Copying and distribution of this file, with or without modification,
+     are permitted in any medium without royalty provided the copyright
+     notice and this notice are preserved.  -->
+
+<!DOCTYPE feature SYSTEM "gdb-target.dtd">
+<feature name="org.gnu.gdb.nanomips.cpu">
+  <reg name="r0" bitsize="64"/>
+  <reg name="r1" bitsize="64"/>
+  <reg name="r2" bitsize="64"/>
+  <reg name="r3" bitsize="64"/>
+  <reg name="r4" bitsize="64"/>
+  <reg name="r5" bitsize="64"/>
+  <reg name="r6" bitsize="64"/>
+  <reg name="r7" bitsize="64"/>
+  <reg name="r8" bitsize="64"/>
+  <reg name="r9" bitsize="64"/>
+  <reg name="r10" bitsize="64"/>
+  <reg name="r11" bitsize="64"/>
+  <reg name="r12" bitsize="64"/>
+  <reg name="r13" bitsize="64"/>
+  <reg name="r14" bitsize="64"/>
+  <reg name="r15" bitsize="64"/>
+  <reg name="r16" bitsize="64"/>
+  <reg name="r17" bitsize="64"/>
+  <reg name="r18" bitsize="64"/>
+  <reg name="r19" bitsize="64"/>
+  <reg name="r20" bitsize="64"/>
+  <reg name="r21" bitsize="64"/>
+  <reg name="r22" bitsize="64"/>
+  <reg name="r23" bitsize="64"/>
+  <reg name="r24" bitsize="64"/>
+  <reg name="r25" bitsize="64"/>
+  <reg name="r26" bitsize="64"/>
+  <reg name="r27" bitsize="64"/>
+  <reg name="r28" bitsize="64"/>
+  <reg name="r29" bitsize="64"/>
+  <reg name="r30" bitsize="64"/>
+  <reg name="r31" bitsize="64"/>
+
+  <reg name="pc" bitsize="64"/>
+</feature>
diff --git a/gdb/features/nanomips64-dsp.xml b/gdb/features/nanomips64-dsp.xml
new file mode 100644
index 00000000000..84bf7b06cc6
--- /dev/null
+++ b/gdb/features/nanomips64-dsp.xml
@@ -0,0 +1,20 @@ 
+<?xml version="1.0"?>
+<!-- Copyright (C) 2018-2022 Free Software Foundation, Inc.
+
+     Copying and distribution of this file, with or without modification,
+     are permitted in any medium without royalty provided the copyright
+     notice and this notice are preserved.  -->
+
+<!DOCTYPE feature SYSTEM "gdb-target.dtd">
+<feature name="org.gnu.gdb.nanomips.dsp">
+  <reg name="hi0" bitsize="64"/>
+  <reg name="lo0" bitsize="64"/>
+  <reg name="hi1" bitsize="64"/>
+  <reg name="lo1" bitsize="64"/>
+  <reg name="hi2" bitsize="64"/>
+  <reg name="lo2" bitsize="64"/>
+  <reg name="hi3" bitsize="64"/>
+  <reg name="lo3" bitsize="64"/>
+
+  <reg name="dspctl" bitsize="32"/>
+</feature>
diff --git a/gdb/nanomips-tdep.c b/gdb/nanomips-tdep.c
new file mode 100644
index 00000000000..664d5d30a3a
--- /dev/null
+++ b/gdb/nanomips-tdep.c
@@ -0,0 +1,3407 @@ 
+/* Target-dependent code for the nanoMIPS architecture, for GDB,
+   the GNU Debugger.
+
+   Copyright (C) 2017-2022 Free Software Foundation, Inc.
+   Contributed by:
+    Jaydeep Patil <jaydeep.patil@imgtec.com>
+    Matthew Fortune <matthew.fortune@imgtec.com>
+    Maciej W. Rozycki <macro@mips.com>
+    Stefan Markovic <stefan.markovic@mips.com>
+    Sara Popadic <sara.popadic@imgtec.com>
+    Dragan Mladjenovic <dragan.mladjenovic@syrmia.com>
+    Aleksandar Rikalo <aleksandar.rikalo@syrmia.com>
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#include "defs.h"
+#include "frame.h"
+#include "inferior.h"
+#include "symtab.h"
+#include "value.h"
+#include "gdbcmd.h"
+#include "language.h"
+#include "gdbcore.h"
+#include "symfile.h"
+#include "objfiles.h"
+#include "gdbtypes.h"
+#include "target.h"
+#include "arch-utils.h"
+#include "regcache.h"
+#include "osabi.h"
+#include "nanomips-tdep.h"
+#include "block.h"
+#include "reggroups.h"
+#include "opcode/nanomips.h"
+#include "elf/mips-common.h"
+#include "elf/nanomips.h"
+#include "elf-bfd.h"
+#include "symcat.h"
+#include "sim-regno.h"
+#include "dis-asm.h"
+#include "disasm.h"
+#include "frame-unwind.h"
+#include "frame-base.h"
+#include "trad-frame.h"
+#include "infcall.h"
+#include "floatformat.h"
+#include "remote.h"
+#include "target-descriptions.h"
+#include "dwarf2/frame.h"
+#include "user-regs.h"
+#include "valprint.h"
+#include "ax.h"
+#include "target-float.h"
+#include <algorithm>
+
+#include "features/nanomips.c"
+
+/* The sizes of registers.  */
+
+enum
+{
+  NANOMIPS32_REGSIZE = 4,
+  NANOMIPS64_REGSIZE = 8
+};
+
+static const char *const nanomips_abi_strings[] = {
+  "auto",
+  "p32",
+  "p64",
+  NULL
+};
+
+/* Enum describing the different kinds of breakpoints.  */
+
+enum nanomips_breakpoint_kind
+{
+  /* 16-bit breakpoint.  */
+  NANOMIPS_BP_KIND_16 = 3,
+
+  /* 32-bit breakpoint.  */
+  NANOMIPS_BP_KIND_32 = 5,
+};
+
+/* The standard register names, and all the valid aliases for them.  */
+struct register_alias
+{
+  const char *name;
+  int regnum;
+};
+
+
+static unsigned int nanomips_debug = 0;
+
+const struct nanomips_regnum *
+nanomips_regnum (struct gdbarch *gdbarch)
+{
+  return gdbarch_tdep<nanomips_gdbarch_tdep> (gdbarch)->regnum;
+}
+
+static int
+nanomips_fp_arg_regnum (struct gdbarch *gdbarch)
+{
+  gdb_assert (nanomips_regnum (gdbarch)->fpr != -1);
+
+  return nanomips_regnum (gdbarch)->fpr + NANOMIPS_FP0_REGNUM;
+}
+
+/* Return 1 if REGNUM refers to a floating-point general register, raw
+   or cooked.  Otherwise return 0.  */
+
+static int
+nanomips_float_register_p (struct gdbarch *gdbarch, int regnum)
+{
+  int rawnum = regnum % gdbarch_num_regs (gdbarch);
+  int fprnum = nanomips_regnum (gdbarch)->fpr;
+
+  return (fprnum != -1
+	  && rawnum >= fprnum + NANOMIPS_FP0_REGNUM
+	  && rawnum < fprnum + NANOMIPS_FCSR_REGNUM);
+}
+
+/* Return 1 if REGNUM refers to a floating-point control register, raw
+   or cooked.  Otherwise return 0.  */
+
+static int
+nanomips_float_control_register_p (struct gdbarch *gdbarch, int regnum)
+{
+  int rawnum = regnum % gdbarch_num_regs (gdbarch);
+  int fprnum = nanomips_regnum (gdbarch)->fpr;
+
+  return (fprnum != -1
+	  && (rawnum == fprnum + NANOMIPS_FCSR_REGNUM
+	      || rawnum == fprnum + NANOMIPS_FIR_REGNUM));
+}
+
+/* Return 1 if REGNUM refers to a DSP accumulator register, raw or cooked.
+   Otherwise return 0.  */
+
+static int
+nanomips_dspacc_register_p (struct gdbarch *gdbarch, int regnum)
+{
+  int rawnum = regnum % gdbarch_num_regs (gdbarch);
+  int dspnum = nanomips_regnum (gdbarch)->dsp;
+
+  return (dspnum != -1
+	  && rawnum >= dspnum + NANOMIPS_DSPHI0_REGNUM
+	  && rawnum < dspnum + NANOMIPS_DSPCTL_REGNUM);
+}
+
+#define FPU_TYPE(gdbarch) (gdbarch_tdep<nanomips_gdbarch_tdep> (gdbarch)->fpu_type)
+
+/* Return the nanoMIPS ABI associated with GDBARCH.  */
+enum nanomips_abi
+nanomips_abi (struct gdbarch *gdbarch)
+{
+  return (gdbarch_tdep<nanomips_gdbarch_tdep> (gdbarch))->nanomips_abi;
+}
+
+int
+nanomips_isa_regsize (struct gdbarch *gdbarch)
+{
+  return gdbarch_tdep<nanomips_gdbarch_tdep> (gdbarch)->register_size;
+}
+
+/* Return the currently configured (or set) saved register size.  */
+
+unsigned int
+nanomips_abi_regsize (struct gdbarch *gdbarch)
+{
+  switch (nanomips_abi (gdbarch))
+    {
+    case NANOMIPS_ABI_P32:
+      return 4;
+    case NANOMIPS_ABI_P64:
+      return 8;
+    case NANOMIPS_ABI_UNKNOWN:
+    default:
+      internal_error_loc (__FILE__, __LINE__, _("bad switch"));
+    }
+}
+
+static void
+nanomips_xfer_register (struct gdbarch *gdbarch, struct regcache *regcache,
+        int reg_num, int length,
+        enum bfd_endian endian, gdb_byte *in,
+        const gdb_byte *out, int buf_offset)
+{
+  int reg_offset = 0;
+
+  gdb_assert (reg_num >= gdbarch_num_regs (gdbarch));
+  /* Need to transfer the left or right part of the register, based on
+     the targets byte order.  */
+  switch (endian)
+    {
+    case BFD_ENDIAN_BIG:
+      reg_offset = register_size (gdbarch, reg_num) - length;
+      break;
+    case BFD_ENDIAN_LITTLE:
+      reg_offset = 0;
+      break;
+    case BFD_ENDIAN_UNKNOWN:  /* Indicates no alignment.  */
+      reg_offset = 0;
+      break;
+    default:
+      internal_error_loc (__FILE__, __LINE__, _("bad switch"));
+    }
+  if (nanomips_debug)
+    gdb_printf (gdb_stderr,
+      "xfer $%d, reg offset %d, buf offset %d, length %d, ",
+      reg_num, reg_offset, buf_offset, length);
+  if (nanomips_debug && out != NULL)
+    {
+      int i;
+      gdb_printf (gdb_stdlog, "out ");
+      for (i = 0; i < length; i++)
+  gdb_printf (gdb_stdlog, "%02x", out[buf_offset + i]);
+    }
+  if (in != NULL)
+    regcache->cooked_read_part (reg_num, reg_offset, length, in + buf_offset);
+  if (out != NULL)
+    regcache->cooked_write_part (reg_num, reg_offset, length, out + buf_offset);
+  if (nanomips_debug && in != NULL)
+    {
+      int i;
+      gdb_printf (gdb_stdlog, "in ");
+      for (i = 0; i < length; i++)
+  gdb_printf (gdb_stdlog, "%02x", in[buf_offset + i]);
+    }
+  if (nanomips_debug)
+    gdb_printf (gdb_stdlog, "\n");
+}
+
+#define VM_MIN_ADDRESS (CORE_ADDR)0x400000
+
+static CORE_ADDR heuristic_proc_start (struct gdbarch *, CORE_ADDR);
+
+static void reinit_frame_cache_sfunc (const char *, int, struct cmd_list_element *);
+
+/* The list of available "set nanomips " and "show nanomips " commands.  */
+
+static struct cmd_list_element *setnanomipscmdlist = NULL;
+static struct cmd_list_element *shownanomipscmdlist = NULL;
+
+/* Return the name of the register corresponding to REGNO.  */
+
+static const char *
+nanomips_register_name (struct gdbarch *gdbarch, int regno)
+{
+  /* GPR names for p32 and p64 ABIs.  */
+  static const char *const gpr_names[]  = {
+    "zero", "at", "t4", "t5", "a0", "a1", "a2", "a3",
+    "a4", "a5", "a6", "a7", "t0", "t1", "t2", "t3",
+    "s0", "s1", "s2", "s3", "s4", "s5", "s6", "s7",
+    "t8", "t9", "k0", "k1", "gp", "sp", "raw_fp", "ra"
+  };
+
+  const char *name;
+  /* Map [gdbarch_num_regs .. 2*gdbarch_num_regs) onto the raw registers,
+     but then don't make the raw register names visible.  This (upper)
+     range of user visible register numbers are the pseudo-registers.
+
+     This approach was adopted accommodate the following scenario:
+     It is possible to debug a 64-bit device using a 32-bit
+     programming model.  In such instances, the raw registers are
+     configured to be 64-bits wide, while the pseudo registers are
+     configured to be 32-bits wide.  The registers that the user
+     sees - the pseudo registers - match the users expectations
+     given the programming model being used.  */
+  int rawnum = regno % gdbarch_num_regs (gdbarch);
+  if (regno < gdbarch_num_regs (gdbarch))
+    return "";
+
+  name = tdesc_register_name (gdbarch, rawnum);
+
+  if (rawnum >= 0 && rawnum < 32)
+    {
+      gdb_assert (name != NULL && name[0] != 0);
+      gdb_assert ((sizeof (gpr_names) / sizeof (gpr_names[0])) == 32);
+      return gpr_names[rawnum];
+    }
+
+  return name;
+}
+
+/* Return the groups that a nanoMIPS register can be categorised into.  */
+
+static int
+nanomips_register_reggroup_p (struct gdbarch *gdbarch, int regnum,
+			      const struct reggroup *reggroup)
+{
+  int vector_p;
+  int float_p;
+  int raw_p;
+  int rawnum = regnum % gdbarch_num_regs (gdbarch);
+  int pseudo = regnum / gdbarch_num_regs (gdbarch);
+  if (reggroup == all_reggroup)
+    return pseudo;
+  vector_p = (register_type (gdbarch, regnum))->is_vector ();
+  float_p = (nanomips_float_register_p (gdbarch, rawnum)
+	     || nanomips_float_control_register_p (gdbarch, rawnum));
+  /* FIXME: cagney/2003-04-13: Can't yet use gdbarch_num_regs
+     (gdbarch), as not all architectures are multi-arch.  */
+  raw_p = rawnum < gdbarch_num_regs (gdbarch);
+  if (gdbarch_register_name (gdbarch, regnum) == NULL
+      || gdbarch_register_name (gdbarch, regnum)[0] == '\0')
+    return 0;
+  if (reggroup == float_reggroup)
+    return float_p && pseudo;
+  if (reggroup == vector_reggroup)
+    return vector_p && pseudo;
+  if (reggroup == general_reggroup)
+    return (!vector_p && !float_p) && pseudo;
+  /* Save the pseudo registers.  Need to make certain that any code
+     extracting register values from a saved register cache also uses
+     pseudo registers.  */
+  if (reggroup == save_reggroup)
+    return raw_p && pseudo;
+  /* Restore the same pseudo register.  */
+  if (reggroup == restore_reggroup)
+    return raw_p && pseudo;
+  return 0;
+}
+
+/* Return the groups that a nanoMIPS register can be categorised into.
+   This version is only used if we have a target description which
+   describes real registers (and their groups).  */
+
+static int
+nanomips_tdesc_register_reggroup_p (struct gdbarch *gdbarch, int regnum,
+				    const struct reggroup *reggroup)
+{
+  int rawnum = regnum % gdbarch_num_regs (gdbarch);
+  int pseudo = regnum / gdbarch_num_regs (gdbarch);
+  int ret;
+
+  /* Only save, restore, and display the pseudo registers.  Need to
+     make certain that any code extracting register values from a
+     saved register cache also uses pseudo registers.
+
+     Note: saving and restoring the pseudo registers is slightly
+     strange; if we have 64 bits, we should save and restore all
+     64 bits.  But this is hard and has little benefit.  */
+  if (!pseudo)
+    return 0;
+
+  ret = tdesc_register_in_reggroup_p (gdbarch, rawnum, reggroup);
+  if (ret != -1)
+    return ret;
+
+  return nanomips_register_reggroup_p (gdbarch, regnum, reggroup);
+}
+
+/* Map the symbol table registers which live in the range [1 *
+   gdbarch_num_regs .. 2 * gdbarch_num_regs) back onto the corresponding raw
+   registers.  Take care of alignment and size problems.  */
+
+static enum register_status
+nanomips_pseudo_register_read (struct gdbarch *gdbarch,
+			       struct readable_regcache *regcache,
+			       int cookednum, gdb_byte *buf)
+{
+  int rawnum = cookednum % gdbarch_num_regs (gdbarch);
+  gdb_assert (cookednum >= gdbarch_num_regs (gdbarch)
+	      && cookednum < 2 * gdbarch_num_regs (gdbarch));
+  if (register_size (gdbarch, rawnum) == register_size (gdbarch, cookednum))
+    return regcache->raw_read (rawnum, buf);
+  else if (register_size (gdbarch, rawnum) >
+	   register_size (gdbarch, cookednum))
+    {
+      enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
+      LONGEST regval;
+      enum register_status status;
+
+      status = regcache->raw_read (rawnum, &regval);
+      if (status == REG_VALID)
+        store_signed_integer (buf, 4, byte_order, regval);
+      return status;
+    }
+  else
+    internal_error_loc (__FILE__, __LINE__, _("bad register size"));
+}
+
+static void
+nanomips_pseudo_register_write (struct gdbarch *gdbarch,
+				struct regcache *regcache, int cookednum,
+				const gdb_byte *buf)
+{
+  int rawnum = cookednum % gdbarch_num_regs (gdbarch);
+  gdb_assert (cookednum >= gdbarch_num_regs (gdbarch)
+	      && cookednum < 2 * gdbarch_num_regs (gdbarch));
+  if (register_size (gdbarch, rawnum) == register_size (gdbarch, cookednum))
+    regcache->raw_write (rawnum, buf);
+  else if (register_size (gdbarch, rawnum) >
+	   register_size (gdbarch, cookednum))
+    {
+      /* Sign extend the shortened version of the register prior
+         to placing it in the raw register.  This is required for
+         some mips64 parts in order to avoid unpredictable behavior.  */
+      enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
+      LONGEST regval = extract_signed_integer (buf, 4, byte_order);
+      regcache_raw_write_signed (regcache, rawnum, regval);
+    }
+  else
+    internal_error_loc (__FILE__, __LINE__, _("bad register size"));
+}
+
+static int
+nanomips_ax_pseudo_register_collect (struct gdbarch *gdbarch,
+				     struct agent_expr *ax, int reg)
+{
+  int rawnum = reg % gdbarch_num_regs (gdbarch);
+  gdb_assert (reg >= gdbarch_num_regs (gdbarch)
+	      && reg < 2 * gdbarch_num_regs (gdbarch));
+
+  ax_reg_mask (ax, rawnum);
+
+  return 0;
+}
+
+static int
+nanomips_ax_pseudo_register_push_stack (struct gdbarch *gdbarch,
+				    struct agent_expr *ax, int reg)
+{
+  int rawnum = reg % gdbarch_num_regs (gdbarch);
+  gdb_assert (reg >= gdbarch_num_regs (gdbarch)
+	      && reg < 2 * gdbarch_num_regs (gdbarch));
+  if (register_size (gdbarch, rawnum) >= register_size (gdbarch, reg))
+    {
+      ax_reg (ax, rawnum);
+
+      if (register_size (gdbarch, rawnum) > register_size (gdbarch, reg))
+        {
+	  if (gdbarch_byte_order (gdbarch) != BFD_ENDIAN_BIG)
+	    {
+	      ax_const_l (ax, 32);
+	      ax_simple (ax, aop_lsh);
+	    }
+	  ax_const_l (ax, 32);
+	  ax_simple (ax, aop_rsh_signed);
+	}
+    }
+  else
+    internal_error_loc (__FILE__, __LINE__, _("bad register size"));
+
+  return 0;
+}
+
+/* Table to translate nanomips 3-bit register field to
+   actual register number.  */
+static const signed char reg3_to_reg[8] = { 16, 17, 18, 19, 4, 5, 6, 7 };
+
+/* Heuristic_proc_start may hunt through the text section for a long
+   time across a 2400 baud serial line.  Allows the user to limit this
+   search.  */
+
+static int heuristic_fence_post = 0;
+
+/* Convert to/from a register and the corresponding memory value.  */
+
+/* This predicate tests for the case of a 4 byte floating point
+   value that is being transferred to or from a floating point
+   register which is 8 bytes wide.  */
+
+static int
+nanomips_convert_register_float_case_p (struct gdbarch *gdbarch, int regnum,
+					struct type *type)
+{
+  return (register_size (gdbarch, regnum) == 8
+	  && nanomips_float_register_p (gdbarch, regnum)
+	  && type->code () == TYPE_CODE_FLT && type->length () == 4);
+}
+
+/* This predicate tests for the case of a value of less than 8
+   bytes in width that is being transfered to or from an 8 byte
+   general purpose register.  */
+static int
+nanomips_convert_register_gpreg_case_p (struct gdbarch *gdbarch, int regnum,
+					struct type *type)
+{
+  int num_regs = gdbarch_num_regs (gdbarch);
+
+  return (register_size (gdbarch, regnum) == 8
+          && regnum % num_regs > 0 && regnum % num_regs < 32
+          && type->length () < 8);
+}
+
+static int
+nanomips_convert_register_p (struct gdbarch *gdbarch,
+			     int regnum, struct type *type)
+{
+  return (nanomips_convert_register_float_case_p (gdbarch, regnum, type)
+	  || nanomips_convert_register_gpreg_case_p (gdbarch, regnum, type));
+}
+
+static int
+nanomips_register_to_value (frame_info_ptr frame, int regnum,
+			    struct type *type, gdb_byte *to,
+			    int *optimizedp, int *unavailablep)
+{
+  struct gdbarch *gdbarch = get_frame_arch (frame);
+
+  if (nanomips_convert_register_float_case_p (gdbarch, regnum, type))
+    {
+      /* single comes from low half of 64-bit register */
+      if (gdbarch_byte_order (gdbarch) == BFD_ENDIAN_BIG)
+	{
+	  if (!get_frame_register_bytes (frame, regnum, 4, {to + 0, 4},
+					 optimizedp, unavailablep))
+	    return 0;
+	}
+      else
+	{
+	  if (!get_frame_register_bytes (frame, regnum, 0, {to + 0, 4},
+					 optimizedp, unavailablep))
+	    return 0;
+	}
+      *optimizedp = *unavailablep = 0;
+      return 1;
+    }
+  else if (nanomips_convert_register_gpreg_case_p (gdbarch, regnum, type))
+    {
+      int len = type->length ();
+      CORE_ADDR offset;
+
+      offset = gdbarch_byte_order (gdbarch) == BFD_ENDIAN_BIG ? 8 - len : 0;
+      if (!get_frame_register_bytes (frame, regnum, offset, {to, (size_t)len},
+				     optimizedp, unavailablep))
+	return 0;
+
+      *optimizedp = *unavailablep = 0;
+      return 1;
+    }
+  else
+    {
+      internal_error_loc (__FILE__, __LINE__,
+                      _("nanomips_register_to_value: unrecognized case"));
+    }
+}
+
+static void
+nanomips_value_to_register (frame_info_ptr frame, int regnum,
+			    struct type *type, const gdb_byte *from)
+{
+  struct gdbarch *gdbarch = get_frame_arch (frame);
+
+  if (nanomips_convert_register_float_case_p (gdbarch, regnum, type))
+    {
+      /* single goes in low half of 64-bit register */
+      if (gdbarch_byte_order (gdbarch) == BFD_ENDIAN_BIG)
+	put_frame_register_bytes (frame, regnum, 4, {from, 4});
+      else
+	put_frame_register_bytes (frame, regnum, 0, {from, 4});
+    }
+  else if (nanomips_convert_register_gpreg_case_p (gdbarch, regnum, type))
+    {
+      gdb_byte fill[8];
+      int len = type->length ();
+
+      /* Sign extend values, irrespective of type, that are stored to
+         a 64-bit general purpose register.  (32-bit unsigned values
+	 are stored as signed quantities within a 64-bit register.
+	 When performing an operation, in compiled code, that combines
+	 a 32-bit unsigned value with a signed 64-bit value, a type
+	 conversion is first performed that zeroes out the high 32 bits.)  */
+      if (gdbarch_byte_order (gdbarch) == BFD_ENDIAN_BIG)
+	{
+	  if (from[0] & 0x80)
+	    store_signed_integer (fill, 8, BFD_ENDIAN_BIG, -1);
+	  else
+	    store_signed_integer (fill, 8, BFD_ENDIAN_BIG, 0);
+	  put_frame_register_bytes (frame, regnum, 0, {fill, (size_t)(8 - len)});
+	  put_frame_register_bytes (frame, regnum, 8 - len, {from, (size_t)len});
+	}
+      else
+	{
+	  if (from[len-1] & 0x80)
+	    store_signed_integer (fill, 8, BFD_ENDIAN_LITTLE, -1);
+	  else
+	    store_signed_integer (fill, 8, BFD_ENDIAN_LITTLE, 0);
+	  put_frame_register_bytes (frame, regnum, 0, {from, (size_t)len});
+	  put_frame_register_bytes (frame, regnum, len, {fill, (size_t)(8 - len)});
+	}
+    }
+  else
+    {
+      internal_error_loc (__FILE__, __LINE__,
+                      _("nanomips_value_to_register: unrecognized case"));
+    }
+}
+
+/* Return the GDB type for the pseudo register REGNUM, which is the
+   ABI-level view.  This function is only called if there is a target
+   description which includes registers, so we know precisely the
+   types of hardware registers.  */
+
+static struct type *
+nanomips_pseudo_register_type (struct gdbarch *gdbarch, int regnum)
+{
+  const int num_regs = gdbarch_num_regs (gdbarch);
+  int rawnum = regnum % num_regs;
+  struct type *rawtype;
+
+  gdb_assert (regnum >= num_regs && regnum < 2 * num_regs);
+
+  /* Absent registers are still absent.  */
+  rawtype = gdbarch_register_type (gdbarch, rawnum);
+  if (rawtype->length () == 0)
+    return rawtype;
+
+  /* Present the floating point registers however the hardware did;
+     do not try to convert between FPU layouts.  */
+  if (nanomips_float_register_p (gdbarch, rawnum))
+    return rawtype;
+
+  /* Floating-point control registers are always 32-bit even though for
+     backwards compatibility reasons 64-bit targets will transfer them
+     as 64-bit quantities even if using XML descriptions.  */
+  if (nanomips_float_control_register_p (gdbarch, rawnum))
+    return builtin_type (gdbarch)->builtin_int32;
+
+  /* Use pointer types for registers if we can.  For n32 we can not,
+     since we do not have a 64-bit pointer type.  */
+  if (nanomips_abi_regsize (gdbarch)
+      == (builtin_type (gdbarch)->builtin_data_ptr)->length())
+    {
+      if (rawnum == NANOMIPS_SP_REGNUM
+	  || rawnum == nanomips_regnum (gdbarch)->badvaddr)
+	return builtin_type (gdbarch)->builtin_data_ptr;
+      else if (rawnum == NANOMIPS_PC_REGNUM)
+	return builtin_type (gdbarch)->builtin_func_ptr;
+    }
+
+  if (nanomips_abi_regsize (gdbarch) == 4 && rawtype->length () == 8
+      && ((rawnum >= NANOMIPS_ZERO_REGNUM && rawnum <= NANOMIPS_PC_REGNUM)
+	  || rawnum == nanomips_regnum (gdbarch)->badvaddr
+	  || rawnum == nanomips_regnum (gdbarch)->status
+	  || rawnum == nanomips_regnum (gdbarch)->cause
+	  || nanomips_dspacc_register_p (gdbarch, rawnum)))
+    return builtin_type (gdbarch)->builtin_int32;
+
+  /* For all other registers, pass through the hardware type.  */
+  return rawtype;
+}
+
+/* Should the upper word of 64-bit addresses be zeroed?  */
+static enum auto_boolean mask_address_var = AUTO_BOOLEAN_AUTO;
+
+static int
+nanomips_mask_address_p (const struct nanomips_gdbarch_tdep *tdep)
+{
+  switch (mask_address_var)
+    {
+    case AUTO_BOOLEAN_TRUE:
+      return 1;
+    case AUTO_BOOLEAN_FALSE:
+      return 0;
+      break;
+    case AUTO_BOOLEAN_AUTO:
+      return tdep->default_mask_address_p;
+    default:
+      internal_error_loc (__FILE__, __LINE__,
+		      _("nanomips_mask_address_p: bad switch"));
+      return -1;
+    }
+}
+
+static void
+show_mask_address (struct ui_file *file, int from_tty,
+		   struct cmd_list_element *c, const char *value)
+{
+  struct nanomips_gdbarch_tdep *tdep = (struct nanomips_gdbarch_tdep*) (target_gdbarch ());
+
+  deprecated_show_value_hack (file, from_tty, c, value);
+  switch (mask_address_var)
+    {
+    case AUTO_BOOLEAN_TRUE:
+      gdb_printf ("The 32 bit nanomips address mask is enabled\n");
+      break;
+    case AUTO_BOOLEAN_FALSE:
+      gdb_printf ("The 32 bit nanomips address mask is disabled\n");
+      break;
+    case AUTO_BOOLEAN_AUTO:
+      gdb_printf
+	("The 32 bit address mask is set automatically.  Currently %s\n",
+	 nanomips_mask_address_p (tdep) ? "enabled" : "disabled");
+      break;
+    default:
+      internal_error_loc (__FILE__, __LINE__, _("show_mask_address: bad switch"));
+      break;
+    }
+}
+
+/* nanoMIPS believes that the PC has a sign extended value.  Perhaps
+   all registers should be sign extended for simplicity?  */
+
+static CORE_ADDR
+nanomips_read_pc (struct readable_regcache *regcache)
+{
+  int regnum = gdbarch_pc_regnum (regcache->arch ());
+  LONGEST pc;
+
+  regcache->cooked_read (regnum, &pc);
+  return pc;
+}
+
+static CORE_ADDR
+nanomips_unwind_pc (struct gdbarch *gdbarch, frame_info_ptr next_frame)
+{
+  return frame_unwind_register_signed
+	   (next_frame, gdbarch_pc_regnum (gdbarch));
+}
+
+static CORE_ADDR
+nanomips_unwind_sp (struct gdbarch *gdbarch, frame_info_ptr next_frame)
+{
+  return frame_unwind_register_signed
+	   (next_frame, gdbarch_num_regs (gdbarch) + NANOMIPS_SP_REGNUM);
+}
+
+/* Assuming THIS_FRAME is a dummy, return the frame ID of that
+   dummy frame.  The frame ID's base needs to match the TOS value
+   saved by save_dummy_frame_tos(), and the PC match the dummy frame's
+   breakpoint.  */
+
+static struct frame_id
+nanomips_dummy_id (struct gdbarch *gdbarch, frame_info_ptr this_frame)
+{
+  return frame_id_build
+	   (get_frame_register_signed (this_frame,
+				       gdbarch_num_regs (gdbarch)
+				       + NANOMIPS_SP_REGNUM),
+	    get_frame_pc (this_frame));
+}
+
+/* Implement the "write_pc" gdbarch method.  */
+
+void
+nanomips_write_pc (struct regcache *regcache, CORE_ADDR pc)
+{
+  int regnum = gdbarch_pc_regnum (regcache->arch ());
+  regcache_cooked_write_unsigned (regcache, regnum, pc);
+}
+
+/* Fetch and return 16-bit instruction from the specified location.  */
+
+static ULONGEST
+nanomips_fetch_stack_slot (struct gdbarch *gdbarch, CORE_ADDR sp, int offset)
+{
+  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
+  return read_memory_unsigned_integer (sp + offset, 4, byte_order);
+}
+
+static ULONGEST
+nanomips_fetch_instruction (struct gdbarch *gdbarch,
+			    CORE_ADDR addr, int *errp)
+{
+  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
+  gdb_byte buf[INSN16_SIZE];
+  int err;
+
+  err = target_read_memory (addr, buf, INSN16_SIZE);
+  if (errp != NULL)
+    *errp = err;
+  if (err != 0)
+    {
+      if (errp == NULL)
+	memory_error (TARGET_XFER_E_IO, addr);
+      return 0;
+    }
+  return extract_unsigned_integer (buf, INSN16_SIZE, byte_order);
+}
+
+/* MicroMIPS instruction fields.  */
+#define micromips_op(x) ((x) >> 10)
+
+/* 16-bit/32-bit-high-part instruction formats, B and S refer to the lowest
+   bit and the size respectively of the field extracted.  */
+#define b0s4_imm(x) ((x) & 0xf)
+#define b0s5_imm(x) ((x) & 0x1f)
+#define b0s5_reg(x) ((x) & 0x1f)
+#define b0s7_imm(x) ((x) & 0x7f)
+#define b0s8_imm(x) ((x) & 0xff)
+#define b0s10_imm(x) ((x) & 0x3ff)
+#define b0u13_15s1_imm(x) (((x) & 0x1fff) | (((x) & 0x8000) >> 2))
+#define b1s4_imm(x) (((x) >> 1) & 0xf)
+#define b1s9_imm(x) (((x) >> 1) & 0x1ff)
+#define b2s1_op(x) (((x) >> 2) & 0x1)
+#define b2s3_cc(x) (((x) >> 2) & 0x7)
+#define b3s2_op(x) (((x) >> 3) & 0x3)
+#define b3s9_imm(x) (((x) >> 3) & 0x1ff)
+#define b4s2_regl(x) (((x) >> 4) & 0x3)
+#define b4s3_reg(x) (((x) >> 4) & 0x7)
+#define b4s4_imm(x) (((x) >> 4) & 0xf)
+#define b5s5_op(x) (((x) >> 5) & 0x1f)
+#define b5s5_reg(x) (((x) >> 5) & 0x1f)
+#define b6s4_op(x) (((x) >> 6) & 0xf)
+#define b7s3_reg(x) (((x) >> 7) & 0x7)
+#define b8s2_regl(x) (((x) >> 8) & 0x3)
+#define b8s7_op(x) (((x) >> 8) & 0x7f)
+
+/* 32-bit instruction formats, B and S refer to the lowest bit and the size
+   respectively of the field extracted.  */
+#define b0s6_op(x) ((x) & 0x3f)
+#define b0s10_op(x) ((x) & 0x3ff)
+#define b0s11_op(x) ((x) & 0x7ff)
+#define b0s12_imm(x) ((x) & 0xfff)
+#define b0u16_imm(x) ((x) & 0xffff)
+#define b0s21_imm(x) ((x) & 0x1fffff)
+#define b0s26_imm(x) ((x) & 0x3ffffff)
+#define b6s10_ext(x) (((x) >> 6) & 0x3ff)
+#define b9s3_op(x) (((x) >> 9) & 0x7)
+#define b11s5_reg(x) (((x) >> 11) & 0x1f)
+#define b16s5_reg(x) (((x) >> 16) & 0x1f)
+#define b21s5_reg(x) (((x) >> 21) & 0x1f)
+#define b11s7_imm(x) (((x) >> 11) & 0x7f)
+#define b12s4_op(x) (((x) >> 12) & 0xf)
+#define b12s5_op(x) (((x) >> 12) & 0x1f)
+#define b14s2_op(x) (((x) >> 14) & 0x3)
+#define b16s4_imm(x) (((x) >> 16) & 0xf)
+
+/* Return the size in bytes of the instruction INSN encoded in the ISA
+   instruction set.  */
+
+static int
+nanomips_insn_size (ULONGEST insn)
+{
+  if (micromips_op (insn) == 0x18)
+    return 3 * INSN16_SIZE;
+  else if ((micromips_op (insn) & 0x4) == 0x0)
+    return 2 * INSN16_SIZE;
+  else
+    return INSN16_SIZE;
+}
+
+/* Calculate the address of the next nanoMIPS instruction to execute
+   after the instruction at the address PC.  The nanomips_next_pc
+   function supports single_step when the remote target monitor or stub
+   is not developed enough to do a single_step.  It works by decoding the
+   current instruction and predicting where a branch will go.  This isn't
+   hard because all the data is available.  */
+
+static CORE_ADDR
+nanomips_next_pc (struct regcache *regcache, CORE_ADDR pc)
+{
+  struct gdbarch *gdbarch = regcache->arch ();
+  ULONGEST insn;
+  CORE_ADDR offset, sp, ra;
+  int op, sreg, treg, uimm, count;
+  LONGEST val_rs, val_rt;
+
+  insn = nanomips_fetch_instruction (gdbarch, pc, NULL);
+  pc += INSN16_SIZE;
+  switch (nanomips_insn_size (insn))
+    {
+    /* 48-bit instructions.  */
+    case 3 * INSN16_SIZE:
+      /* No branch or jump instructions in this category.  */
+      pc += 2 * INSN16_SIZE;
+      break;
+
+    /* 32-bit instructions.  */
+    case 2 * INSN16_SIZE:
+      insn <<= 16;
+      insn |= nanomips_fetch_instruction (gdbarch, pc, NULL);
+      pc += INSN16_SIZE;
+      switch (micromips_op (insn >> 16))
+      	{
+      	case 0x0: /* P32 */
+      	  op = b5s5_op (insn >> 16);
+      	  switch (op)
+      	    {
+      	    case 0x0: /* P.RI */
+      	      switch (b3s2_op (insn >> 16))
+      		{
+      		case 0x1: /* SYSCALL */
+      		  if (b2s1_op (insn >> 16) == 0)
+      		    {
+      		      struct nanomips_gdbarch_tdep *tdep;
+
+      		      tdep = gdbarch_tdep<nanomips_gdbarch_tdep> (gdbarch);
+      		      if (tdep->syscall_next_pc != NULL)
+      			pc = tdep->syscall_next_pc (get_current_frame (), pc);
+      		    }
+      		  break;
+      		}
+      	      break;
+      	    }
+      	  break;
+
+      	case 0x2: /* MOVE.BALC */
+      	  offset = ((insn & 1) << 20 | ((insn >> 1) & 0xfffff)) << 1;
+      	  offset = (offset ^ 0x200000) - 0x200000;
+      	  pc += offset;
+      	  break;
+
+      	case 0xa: /* BALC, BC */
+      	  offset = ((insn & 1) << 24 | ((insn >> 1) & 0xffffff)) << 1;
+      	  offset = (offset ^ 0x2000000) - 0x2000000;
+      	  pc += offset;
+      	  break;
+
+      	case 0x12: /* P.J P.BREG P.BALRC P.BALRSC */
+      	  op = b12s4_op (insn);
+      	  sreg = b0s5_reg (insn >> 16);
+      	  treg = b5s5_reg (insn >> 16);
+      	  if (op == 0x8) /* BALRSC, BRSC */
+      	    {
+      	      val_rs = regcache_raw_get_signed (regcache, sreg);
+      	      pc += (val_rs << 1);
+      	    }
+      	  else if (op == 0 || op == 1) /* JALRC JALRC.HB */
+      	    pc = regcache_raw_get_signed (regcache, sreg);
+      	  break;
+
+      	case 0x20: /* PP.SR */
+      	  if ((b12s4_op (insn) == 0x3) && ((insn & 3) == 3)) /* RESTORE.JRC */
+      	   {
+                   sp = regcache_raw_get_signed (regcache, NANOMIPS_SP_REGNUM);
+                   ra = regcache_raw_get_signed (regcache, NANOMIPS_RA_REGNUM);
+                   sp += (((insn >> 3) & 0x1ff) << 3);
+                   count = ((insn >> 16) & 0xf);
+                   treg = b5s5_reg(insn >> 16);
+                   if (count != 0 && treg <= 31 && (treg + count) > 31)
+                     ra = nanomips_fetch_stack_slot (gdbarch, sp, -(31 - treg + 1) * 4);
+                   pc = ra;
+                 }
+      	  break;
+
+      	case 0x22: /* P.BR1 */
+      	  op = b14s2_op (insn);
+      	  sreg = b0s5_reg (insn >> 16);
+      	  treg = b5s5_reg (insn >> 16);
+      	  val_rs = regcache_raw_get_signed (regcache, sreg);
+      	  val_rt = regcache_raw_get_signed (regcache, treg);
+      	  offset = ((insn & 1) << 13 | ((insn >> 1) & 0x1fff)) << 1;
+      	  offset = (offset ^ 0x4000) - 0x4000;
+      	  if ((op == 0 && val_rs == val_rt) /* BEQC */
+      	      || (op == 2 && val_rs >= val_rt) /* BGEC */
+      	      || (op == 3
+      		  && (ULONGEST) val_rs >= (ULONGEST) val_rt)) /* BGEUC */
+      	    pc += offset;
+      	  break;
+
+      	case 0x2a: /* P.BR2 */
+      	  op = b14s2_op (insn);
+      	  sreg = b0s5_reg (insn >> 16);
+      	  treg = b5s5_reg (insn >> 16);
+      	  val_rs = regcache_raw_get_signed (regcache, sreg);
+      	  val_rt = regcache_raw_get_signed (regcache, treg);
+      	  offset = ((insn & 1) << 13 | ((insn >> 1) & 0x1fff)) << 1;
+      	  offset = (offset ^ 0x4000) - 0x4000;
+      	  if ((op == 0 && val_rs != val_rt) /* BNEC */
+      	      || (op == 2 && val_rs < val_rt) /* BLTC */
+      	      || (op == 3
+      		  && (ULONGEST) val_rs < (ULONGEST) val_rt)) /* BLTUC */
+      	    pc += offset;
+      	  break;
+
+      	case 0x32: /* P.BRI */
+      	  op = b2s3_cc (insn >> 16);
+      	  treg = b5s5_reg (insn >> 16);
+      	  val_rt = regcache_raw_get_signed (regcache, treg);
+      	  offset = ((insn & 1) << 10 | ((insn >> 1) & 0x3ff)) << 1;
+      	  offset = (offset ^ 0x800) - 0x800;
+      	  uimm = b11s7_imm (insn);
+      	  if ((op == 0 && val_rt == uimm) /* BEQIC */
+                    || (op == 1 && ((val_rt &  (1 << uimm)) == 0)) /* BBEQZC */
+      	      || (op == 2 && val_rt >= uimm) /* BGEIC */
+      	      || (op == 3 && (ULONGEST) val_rt >= uimm) /* BGEIUC */
+      	      || (op == 4 && val_rt != uimm) /* BNEIC */
+                    || (op == 5 && ((val_rt &  (1 << uimm)) != 0)) /* BBNEZC */
+      	      || (op == 6 && val_rt < uimm) /* BLTIC */
+      	      || (op == 7 && (ULONGEST) val_rt < uimm)) /* BLTIUC */
+      	    pc += offset;
+      	  break;
+
+      	case 0x3a: /* P.BZ */
+      	  op = (insn & 0x80000); /* 20th bit */
+      	  treg = b5s5_reg (insn >> 16);
+      	  val_rt = regcache_raw_get_signed (regcache, treg);
+      	  offset = ((insn & 1) << 19 | ((insn >> 1) & 0x7ffff)) << 1;
+      	  offset = (offset ^ 0x100000) - 0x100000;
+      	  if ((op == 0 && val_rt == 0) /* BEQZC */
+      	      || (op != 0 && val_rt != 0)) /* BNEZC */
+      	    pc += offset;
+      	  break;
+
+      	default:
+      	  break;
+      	}
+      break;
+
+    /* 16-bit instructions.  */
+    case INSN16_SIZE:
+      switch (micromips_op (insn))
+	{
+	case 0x4: /* P16 */
+	  op = b5s5_op (insn);
+	  switch (op)
+	    {
+	    case 0x0: /* P16.RI */
+	      switch (b3s2_op (insn))
+		{
+		case 0x1: /* SYSCALL[16] */
+		  if (b2s1_op (insn) == 0)
+		    {
+		      struct nanomips_gdbarch_tdep *tdep;
+
+		      tdep = gdbarch_tdep<nanomips_gdbarch_tdep> (gdbarch);
+		      if (tdep->syscall_next_pc != NULL)
+			pc = tdep->syscall_next_pc (get_current_frame (), pc);
+		    }
+		  break;
+		}
+	      break;
+	    }
+	  break;
+
+	case 0x6: /* BC[16] */
+	case 0xe: /* BALC[16] */
+	  offset = ((insn & 1) << 9 | ((insn >> 1) & 0x1ff)) << 1;
+	  offset = (offset ^ 0x400) - 0x400;
+	  pc += offset;
+	  break;
+
+	case 0x7: /* RESTORE.JRC[16] */
+	  if ((insn & 1) == 0 && (insn & 0x20) == 0x20 && ((insn >> 8) & 1) == 1)
+          {
+            sp = regcache_raw_get_signed (regcache, NANOMIPS_SP_REGNUM);
+	    ra = regcache_raw_get_signed (regcache, NANOMIPS_RA_REGNUM);
+            sp += (((insn >> 4) & 0xf) << 4);
+            count = insn & 0xf;
+            treg = ((insn >> 9) & 0x1) ? NANOMIPS_RA_REGNUM : NANOMIPS_FP_REGNUM;
+            if (count != 0 && treg + count > 31) {
+                ra = nanomips_fetch_stack_slot (gdbarch, sp, -(31 - treg + 1) * 4);
+            }
+            pc = ra;
+          }
+	  break;
+
+	case 0x26: /* BEQZC[16] */
+	  treg = reg3_to_reg[b7s3_reg (insn)];
+	  val_rt = regcache_raw_get_signed (regcache, treg);
+	  offset = ((insn & 1) << 6 | ((insn >> 1) & 0x3f)) << 1;
+	  offset = (offset ^ 0x80) - 0x80;
+	  if (val_rt == 0)
+	    pc += offset;
+	  break;
+
+	case 0x2e: /* BNEZC[16] */
+	  treg = reg3_to_reg[b7s3_reg (insn)];
+	  val_rt = regcache_raw_get_signed (regcache, treg);
+	  offset = ((insn & 1) << 6 | ((insn >> 1) & 0x3f)) << 1;
+	  offset = (offset ^ 0x80) - 0x80;
+	  if (val_rt != 0)
+	    pc += offset;
+	  break;
+
+	case 0x36: /* P16.BR P16.JRC */
+	  sreg = b4s3_reg (insn);
+	  treg = b7s3_reg (insn);
+	  val_rs = regcache_raw_get_signed (regcache, reg3_to_reg[sreg]);
+	  val_rt = regcache_raw_get_signed (regcache, reg3_to_reg[treg]);
+	  offset = insn & 0xf;
+	  /* BEQC[16] BEQC[16] */
+	  if ((sreg < treg && offset != 0 && val_rs == val_rt)
+	      || (sreg >= treg && offset != 0 && val_rs != val_rt))
+	    pc += (offset << 1);
+	  else if (offset == 0) /* JALRC[16] JRC */
+	    pc = regcache_raw_get_signed (regcache, b5s5_reg(insn));
+	  break;
+
+	default:
+	  break;
+	}
+      break;
+
+    default:
+      break;
+    }
+  return pc;
+}
+
+struct nanomips_frame_cache
+{
+  CORE_ADDR base;
+  struct trad_frame_saved_reg *saved_regs;
+};
+
+/* Set a register's saved stack address in temp_saved_regs.  If an
+   address has already been set for this register, do nothing; this
+   way we will only recognize the first save of a given register in a
+   function prologue.
+
+   For simplicity, save the address in both [0 .. gdbarch_num_regs) and
+   [gdbarch_num_regs .. 2*gdbarch_num_regs).
+   Strictly speaking, only the second range is used as it is only second
+   range (the ABI instead of ISA registers) that comes into play when finding
+   saved registers in a frame.  */
+
+static void
+set_reg_offset (struct gdbarch *gdbarch, struct nanomips_frame_cache *this_cache,
+		int regnum, CORE_ADDR offset)
+{
+  if (this_cache != NULL
+      && this_cache->saved_regs[regnum].addr() == -1)
+    {
+      this_cache->saved_regs[regnum + 0 * gdbarch_num_regs (gdbarch)].set_addr(
+        offset);
+      this_cache->saved_regs[regnum + 1 * gdbarch_num_regs (gdbarch)].set_addr(
+        offset);
+    }
+}
+
+/* Analyze the function prologue from START_PC to LIMIT_PC.  Return
+   the address of the first instruction past the prologue.  */
+
+static CORE_ADDR
+nanomips_scan_prologue (struct gdbarch *gdbarch,
+			CORE_ADDR start_pc, CORE_ADDR limit_pc,
+			frame_info_ptr this_frame,
+			struct nanomips_frame_cache *this_cache)
+{
+  CORE_ADDR end_prologue_addr;
+  int prev_non_prologue_insn = 0;
+  int frame_reg = NANOMIPS_SP_REGNUM;
+  int this_non_prologue_insn;
+  int non_prologue_insns = 0;
+  long frame_offset = 0;	/* Size of stack frame.  */
+  long frame_adjust = 0;	/* Offset of FP from SP.  */
+  CORE_ADDR prev_pc;
+  CORE_ADDR cur_pc;
+  ULONGEST insn;		/* current instruction */
+  CORE_ADDR sp;
+  long offset;
+  long sp_adj;
+  long v1_off = 0;		/* The assumption is LUI will replace it.  */
+  int breg;
+  int dreg;
+  int sreg;
+  int treg;
+  int loc;
+  int op;
+
+  /* Can be called when there's no process, and hence when there's no
+     THIS_FRAME.  */
+  if (this_frame != NULL)
+    sp = get_frame_register_signed (this_frame,
+				    gdbarch_num_regs (gdbarch)
+				    + NANOMIPS_SP_REGNUM);
+  else
+    sp = 0;
+
+  if (limit_pc > start_pc + 200)
+    limit_pc = start_pc + 200;
+  prev_pc = start_pc;
+
+  /* Permit at most one non-prologue non-control-transfer instruction
+     in the middle which may have been reordered by the compiler for
+     optimisation.  */
+  for (cur_pc = start_pc; cur_pc < limit_pc; cur_pc += loc)
+    {
+      this_non_prologue_insn = 0;
+      sp_adj = 0;
+      loc = 0;
+      insn = nanomips_fetch_instruction (gdbarch, cur_pc, NULL);
+      loc += INSN16_SIZE;
+      switch (nanomips_insn_size (insn))
+	{
+	/* 48-bit instructions.  */
+	case 3 * INSN16_SIZE:
+	  if (micromips_op (insn) == 0x18)
+	    {
+	      op = b0s5_imm (insn);
+	      treg = b5s5_reg (insn);
+	      offset = nanomips_fetch_instruction (gdbarch, cur_pc + 2, NULL);
+	      offset <<= 16;
+	      offset |= nanomips_fetch_instruction (gdbarch, cur_pc + 4, NULL);
+	      if (op == 0x0 && treg == 3) /* LI48 $v1, imm32 */
+		v1_off = offset;
+	      else if (op == 0x1 /* ADDIU48 $sp, imm32 */
+		       && treg == NANOMIPS_SP_REGNUM)
+		sp_adj = offset;
+	      else
+		this_non_prologue_insn = 1;
+	    }
+	      else
+		this_non_prologue_insn = 1;
+	  break;
+
+	/* 32-bit instructions.  */
+	case 2 * INSN16_SIZE:
+	  insn <<= 16;
+	  insn |= nanomips_fetch_instruction (gdbarch,
+					  cur_pc + loc, NULL);
+	  loc += INSN16_SIZE;
+
+	  switch (micromips_op (insn >> 16))
+	    {
+	    case 0x0: /* PP.ADDIU bits 000000 */
+	      sreg = b0s5_reg (insn >> 16);
+	      treg = b5s5_reg (insn >> 16);
+	      offset = b0u16_imm (insn);
+	      if (sreg == treg
+		  && treg == NANOMIPS_SP_REGNUM) /* ADDIU $sp, $sp, imm */
+		sp_adj = offset;
+	      else if (sreg == NANOMIPS_SP_REGNUM
+		       && treg == NANOMIPS_FP_REGNUM) /* ADDIU $fp, $sp, imm */
+		{
+		  frame_adjust = offset;
+		  frame_reg = NANOMIPS_FP_REGNUM;
+		}
+	      else if (sreg != NANOMIPS_GP_REGNUM
+		       || treg != NANOMIPS_GP_REGNUM)
+		this_non_prologue_insn = 1;
+	      break;
+
+	    case 0x8: /* P32A: bits 001000 */
+	      op = b0s10_op (insn);
+	      sreg = b0s5_reg (insn >> 16);
+	      treg = b5s5_reg (insn >> 16);
+	      dreg = b11s5_reg (insn);
+	      if (op == 0x1d0	/* SUBU: bits 001000 0111010000 */
+		  && dreg == NANOMIPS_SP_REGNUM && sreg == NANOMIPS_SP_REGNUM
+		  && treg == 3)	/* SUBU $sp, $v1 */
+		sp_adj = v1_off;
+	      else
+		this_non_prologue_insn = 1;
+	      break;
+
+	    case 0x20: /* P.U12 bits 100000 */
+	      /* SAVE: bits 100000 rt 0 count 0011 */
+	      if (b12s4_op (insn) == 0x3)
+		{
+		  int rt, this_rt, gp, use_gp;
+		  int counter = 0, count = b16s4_imm (insn);
+		  long this_offset;
+		  offset = b3s9_imm (insn) << 3;
+		  rt = b21s5_reg (insn);
+		  sp_adj = -offset;
+		  gp = (insn >> 2) & 1;
+		  while (counter != count)
+		    {
+		      use_gp = gp & (counter == count - 1);
+		      if (use_gp)
+			this_rt = NANOMIPS_GP_REGNUM;
+		      else
+			this_rt = (((rt >> 4) & 1) << 4) | (rt + counter);
+		      this_offset = (counter + 1) << 2;
+		      set_reg_offset (gdbarch, this_cache, this_rt,
+				      sp + offset - this_offset);
+		      counter++;
+		    }
+		}
+	      else if (b12s4_op (insn) == 8) /* ADDIU[NEG]: bits 100000 1000 */
+		{
+		  sreg = b0s5_reg (insn >> 16);
+		  treg = b5s5_reg (insn >> 16);
+		  if (sreg == treg && sreg == NANOMIPS_SP_REGNUM)
+			  /* ADDIU[NEG] $sp, $sp, imm */
+		    {
+		      offset = b0s11_op (insn);
+		      sp_adj = -offset;
+		    }
+		}
+	      else if (b12s4_op (insn) == 0) /* ORI: bits 100000 0000 */
+		{
+		  sreg = b0s5_reg (insn >> 16);
+		  treg = b5s5_reg (insn >> 16);
+		  if (sreg == treg && treg == 3) /* ORI $v1, $v1, imm */
+		    v1_off |= b0s11_op (insn);
+		  else
+		    this_non_prologue_insn = 1;
+		}
+		else
+		  this_non_prologue_insn = 1;
+	      break;
+
+	    case 0x21: /* P.LS.U12 bits 100001 */
+	      if (b12s4_op (insn) == 0x9) /* SW 100001 1001 */
+		{
+		  breg = b0s5_reg (insn >> 16);
+		  sreg = b5s5_reg (insn >> 16);
+		  offset = b0s12_imm (insn);
+		  if (breg == NANOMIPS_SP_REGNUM) /* SW reg,offset($sp) */
+		    set_reg_offset (gdbarch, this_cache, sreg, sp + offset);
+		  else
+		    this_non_prologue_insn = 1;
+		}
+	      break;
+
+	    case 0x29: /* P.LS.S9 bits 101001 */
+	      if (b8s7_op (insn) == 0x48) /* SW[S9] 101001 1001 0 00 */
+		{
+		  breg = b0s5_reg (insn >> 16);
+		  sreg = b5s5_reg (insn >> 16);
+		  offset = (((insn >> 15) & 1) << 8) | b0s8_imm (insn);
+		  offset = (offset ^ 0x100) - 0x100;
+		  if (breg == NANOMIPS_SP_REGNUM) /* SW[S9] reg,offset($sp) */
+		    set_reg_offset (gdbarch, this_cache, sreg, sp + offset);
+		  else
+		    this_non_prologue_insn = 1;
+		}
+	      break;
+
+	    case 0x38: /* P.LUI bits 111000 */
+	      treg = b5s5_reg (insn >> 16);
+	      if ((insn & 2) == 0 /* LU20I bits 111000 0 */
+		  && treg == 3) /* LU20I $v1, imm */
+		{
+		  v1_off = ((insn & 1) << 19)
+			    | (((insn >> 2) & 0x3ff) << 9)
+			    | (((insn >> 12) & 0x1ff));
+		  v1_off = v1_off << 12;
+		}
+	      else
+		this_non_prologue_insn = 1;
+	      break;
+
+	   default:
+	     this_non_prologue_insn = 1;
+	     break;
+	   }
+
+	  insn >>= 16;
+	  break;
+
+	/* 16-bit instructions.  */
+	case INSN16_SIZE:
+	  switch (micromips_op (insn))
+	    {
+	    case 0x4: /* MOVE: bits 000100 */
+	      sreg = b0s5_reg (insn);
+	      dreg = b5s5_reg (insn);
+	      if (sreg == NANOMIPS_SP_REGNUM && dreg == NANOMIPS_FP_REGNUM)
+				/* MOVE  $fp, $sp */
+		frame_reg = NANOMIPS_FP_REGNUM;
+	      else
+		this_non_prologue_insn = 1;
+	      break;
+
+	    case 0x7: /* SAVE: bits 000111 */
+	      {
+		int rt, rt1, this_rt;
+		int counter = 0, count = b0s4_imm (insn);
+		long this_offset;
+		offset = b4s4_imm (insn) << 4;
+		rt1 = (insn >> 9) & 1;
+		rt = 30 | rt1;
+		sp_adj = -offset;
+		while (counter != count)
+		  {
+		    this_rt = (((rt >> 4) & 1) << 4) | (rt + counter);
+		    this_offset = (counter + 1) << 2;
+		    set_reg_offset (gdbarch, this_cache, this_rt,
+				    sp + offset - this_offset);
+		    counter++;
+		  }
+		break;
+	      }
+
+	    case 0x35: /* SW[SP]: bits 110101 */
+	      treg = b5s5_reg (insn);
+	      offset = b0s5_imm (insn);
+	      set_reg_offset (gdbarch, this_cache, treg, sp + offset);
+	      break;
+
+	    default:
+	      this_non_prologue_insn = 1;
+	      break;
+	    }
+	  break;
+	}
+
+      if (sp_adj < 0)
+	frame_offset -= sp_adj;
+
+      non_prologue_insns += this_non_prologue_insn;
+
+      if (non_prologue_insns > 1 || sp_adj > 0)
+  break;
+
+      prev_non_prologue_insn = this_non_prologue_insn;
+      prev_pc = cur_pc;
+    }
+
+  if (this_cache != NULL)
+    {
+      this_cache->base =
+	(get_frame_register_signed (this_frame,
+				    gdbarch_num_regs (gdbarch) + frame_reg)
+	 + frame_offset - frame_adjust);
+      /* FIXME: brobecker/2004-10-10: Just as in the mips32 case, we should
+	 be able to get rid of the assignment below, evetually. But it's
+	 still needed for now.  */
+      this_cache->saved_regs[gdbarch_num_regs (gdbarch) + NANOMIPS_PC_REGNUM]
+	= this_cache->saved_regs[gdbarch_num_regs (gdbarch)
+				 + NANOMIPS_RA_REGNUM];
+    }
+
+  /* Set end_prologue_addr to the address of the instruction immediately
+     after the last one we scanned.  Unless the last one looked like a
+     non-prologue instruction (and we looked ahead), in which case use
+     its address instead.  */
+  end_prologue_addr
+    = prev_non_prologue_insn ? prev_pc : cur_pc;
+
+  return end_prologue_addr;
+}
+
+/* Heuristic unwinder for procedures using nanoMIPS instructions.
+   Procedures that use the 32-bit instruction set are handled by the
+   mips_insn32 unwinder.  Likewise MIPS16 and the mips_insn16 unwinder. */
+
+static struct nanomips_frame_cache *
+nanomips_frame_cache (frame_info_ptr this_frame, void **this_cache)
+{
+  struct gdbarch *gdbarch = get_frame_arch (this_frame);
+  struct nanomips_frame_cache *cache;
+
+  if ((*this_cache) != NULL)
+    return (struct nanomips_frame_cache *) (*this_cache);
+
+  cache = FRAME_OBSTACK_ZALLOC (struct nanomips_frame_cache);
+  (*this_cache) = cache;
+  cache->saved_regs = trad_frame_alloc_saved_regs (this_frame);
+
+  /* Analyze the function prologue.  */
+  {
+    const CORE_ADDR pc = get_frame_address_in_block (this_frame);
+    CORE_ADDR start_addr;
+
+    find_pc_partial_function (pc, NULL, &start_addr, NULL);
+    if (start_addr == 0)
+      start_addr = heuristic_proc_start (get_frame_arch (this_frame), pc);
+    /* We can't analyze the prologue if we couldn't find the begining
+       of the function.  */
+    if (start_addr == 0)
+      return cache;
+
+    nanomips_scan_prologue (gdbarch, start_addr, pc, this_frame,
+			    (struct nanomips_frame_cache *) *this_cache);
+  }
+
+  /* gdbarch_sp_regnum contains the value and not the address.  */
+  cache->saved_regs[gdbarch_num_regs (gdbarch)
+        + NANOMIPS_SP_REGNUM].set_value (cache->base);
+
+  return (struct nanomips_frame_cache *) (*this_cache);
+}
+
+static void
+nanomips_frame_this_id (frame_info_ptr this_frame, void **this_cache,
+			struct frame_id *this_id)
+{
+  struct nanomips_frame_cache *info = nanomips_frame_cache (this_frame,
+							    this_cache);
+  /* This marks the outermost frame.  */
+  if (info->base == 0)
+    return;
+  (*this_id) = frame_id_build (info->base, get_frame_func (this_frame));
+}
+
+static struct value *
+nanomips_frame_prev_register (frame_info_ptr this_frame,
+			      void **this_cache, int regnum)
+{
+  struct nanomips_frame_cache *info = nanomips_frame_cache (this_frame,
+							    this_cache);
+  return trad_frame_get_prev_register (this_frame, info->saved_regs, regnum);
+}
+
+static int
+nanomips_frame_sniffer (const struct frame_unwind *self,
+			frame_info_ptr this_frame, void **this_cache)
+{
+  return 1;
+}
+
+static const struct frame_unwind nanomips_frame_unwind =
+{
+  "nanoMIPS insn prologue",
+  NORMAL_FRAME,
+  default_frame_unwind_stop_reason,
+  nanomips_frame_this_id,
+  nanomips_frame_prev_register,
+  NULL,
+  nanomips_frame_sniffer
+};
+
+static CORE_ADDR
+nanomips_frame_base_address (frame_info_ptr this_frame,
+			     void **this_cache)
+{
+  struct nanomips_frame_cache *info = nanomips_frame_cache (this_frame,
+							    this_cache);
+  return info->base;
+}
+
+static const struct frame_base nanomips_frame_base =
+{
+  &nanomips_frame_unwind,
+  nanomips_frame_base_address,
+  nanomips_frame_base_address,
+  nanomips_frame_base_address
+};
+
+static const struct frame_base *
+nanomips_frame_base_sniffer (frame_info_ptr this_frame)
+{
+  return &nanomips_frame_base;
+}
+
+/* nanomips_addr_bits_remove - remove useless address bits  */
+
+static CORE_ADDR
+nanomips_addr_bits_remove (struct gdbarch *gdbarch, CORE_ADDR addr)
+{
+  struct nanomips_gdbarch_tdep *tdep = gdbarch_tdep<nanomips_gdbarch_tdep> (gdbarch);
+
+  if (nanomips_mask_address_p (tdep)
+      && (((ULONGEST) addr) >> 32 == 0xffffffffUL))
+    /* This hack is a work-around for existing boards using PMON, the
+       simulator, and any other 64-bit targets that doesn't have true
+       64-bit addressing.  On these targets, the upper 32 bits of
+       addresses are ignored by the hardware.  Thus, the PC or SP are
+       likely to have been sign extended to all 1s by instruction
+       sequences that load 32-bit addresses.  For example, a typical
+       piece of code that loads an address is this:
+
+       lui $r2, <upper 16 bits>
+       ori $r2, <lower 16 bits>
+
+       But the lui sign-extends the value such that the upper 32 bits
+       may be all 1s.  The workaround is simply to mask off these
+       bits.  In the future, gcc may be changed to support true 64-bit
+       addressing, and this masking will have to be disabled.  */
+    return addr &= 0xffffffffUL;
+  else
+    return addr;
+}
+
+
+/* Checks for an atomic sequence of instructions beginning with a LL/LLD
+   instruction and ending with a SC/SCD instruction.  If such a sequence
+   is found, attempt to step through it.  A breakpoint is placed at the end of
+   the sequence.  */
+
+static std::vector<CORE_ADDR>
+nanomips_deal_with_atomic_sequence (struct gdbarch *gdbarch,
+				    CORE_ADDR pc)
+{
+  const int atomic_sequence_length = 16; /* Instruction sequence length.  */
+  int last_breakpoint = 0; /* Defaults to 0 (no breakpoints placed).  */
+  CORE_ADDR breaks[2] = {CORE_ADDR_MAX, CORE_ADDR_MAX};
+  CORE_ADDR branch_bp = 0; /* Breakpoint at branch instruction's
+			      destination.  */
+  CORE_ADDR loc = pc;
+  int sc_found = 0;
+  ULONGEST insn;
+  int insn_count;
+  int index;
+
+  /* Assume all atomic sequences start with a ll/lld instruction.  */
+  insn = nanomips_fetch_instruction (gdbarch, loc, NULL);
+  if (micromips_op (insn) != 0x29)	/* P.LL: bits 101001 */
+    return {};
+  loc += INSN16_SIZE;
+  insn <<= 16;
+  insn |= nanomips_fetch_instruction (gdbarch, loc, NULL);
+  if (b8s7_op (insn) != 0x51)	/* LL: bits 101001 1010 0 01 */
+    return {};
+  loc += INSN16_SIZE;
+
+  /* Assume all atomic sequences end with an sc/scd instruction.  Assume
+     that no atomic sequence is longer than "atomic_sequence_length"
+     instructions.  */
+  for (insn_count = 0;
+       !sc_found && insn_count < atomic_sequence_length;
+       ++insn_count)
+    {
+      int is_branch = 0, op;
+      CORE_ADDR offset;
+
+      insn = nanomips_fetch_instruction (gdbarch, loc, NULL);
+      loc += INSN16_SIZE;
+
+      /* Assume that there is at most one conditional branch in the
+         atomic sequence.  If a branch is found, put a breakpoint in
+         its destination address.  */
+      switch (nanomips_insn_size (insn))
+	{
+	/* 32-bit instructions.  */
+	case 2 * INSN16_SIZE:
+	  insn <<= 16;
+	  insn |= nanomips_fetch_instruction (gdbarch, loc, NULL);
+	  loc += INSN16_SIZE;
+
+	  switch (micromips_op (insn >> 16))
+	    {
+	    case 0xa: /* BALC, BC */
+	      offset = ((insn & 1) << 24 | ((insn >> 1) & 0xffffff)) << 1;
+	      offset = (offset ^ 0x2000000) - 0x2000000;
+	      branch_bp = loc + offset;
+	      is_branch = 1;
+	      break;
+
+	    case 0x12:
+	      op = b12s4_op (insn);
+	      if (op == 0x8) /* BALRC, BALRSC */
+		return {}; /* Fall back to the standard single-step code. */
+	      else if (op == 0 || op == 1) /* JALRC JALRC.HB */
+		return {}; /* Fall back to the standard single-step code. */
+	      break;
+
+	    case 0x20: /* PP.SR */
+	      if (b12s5_op (insn) == 0x13) /* RESTORE.JRC */
+		return {}; /* Fall back to the standard single-step code. */
+	      break;
+
+	    case 0x22: /* P.BR1 */
+	    case 0x2a: /* P.BR2 */
+	      op = b14s2_op (insn);
+	      offset = ((insn & 1) << 13 | ((insn >> 1) & 0x1fff)) << 1;
+	      offset = (offset ^ 0x4000) - 0x4000;
+	      if (op == 0 /* BEQC, BNEC */
+		  || op == 2 /* BGEC, BLTC */
+		  || op == 3) /* BGEUC, BLTUC */
+		{
+		  branch_bp = loc + offset;
+		  is_branch = 1;
+		}
+	      break;
+
+	    case 0x32: /* P.BRI */
+	      op = b2s3_cc (insn >> 16);
+	      offset = ((insn & 1) << 10 | ((insn >> 1) & 0x3ff)) << 1;
+	      offset = (offset ^ 0x800) - 0x800;
+	      if (op == 0 /* BEQIC */
+		  || op == 2 /* BGEIC */
+		  || op == 3 /* BGEIUC */
+		  || op == 4 /* BNEIC */
+		  || op == 6 /* BLTIC */
+		  || op == 7 ) /* BLTIUC */
+		{
+		  branch_bp = loc + offset;
+		  is_branch = 1;
+		}
+	      break;
+
+	    case 0x3a: /* P.BZ */
+	      op = (insn & 0x80000); /* 20th bit */
+	      offset = ((insn & 1) << 19 | ((insn >> 1) & 0x7ffff)) << 1;
+	      offset = (offset ^ 0x100000) - 0x100000;
+	      if (op == 0 /* BEQZC */
+	          || op != 0 ) /* BNEZC */
+		{
+		  branch_bp = loc + offset;
+		  is_branch = 1;
+		}
+	      break;
+
+	    case 0x29: /* P.SC: bits 101001 */
+	      if (b8s7_op (insn) == 0x59) /* SC: bits 101001 1011 0 01 */
+		sc_found = 1;
+	      break;
+	    }
+	  break;
+
+	/* 16-bit instructions.  */
+	case INSN16_SIZE:
+	  switch (micromips_op (insn))
+	    {
+	    case 0x6: /* BC[16] */
+	    case 0xe: /* BALC[16] */
+	      offset = ((insn & 1) << 9 | ((insn >> 1) & 0x1ff)) << 1;
+	      offset = (offset ^ 0x400) - 0x400;
+	      branch_bp = loc + offset;
+	      is_branch = 1;
+	      break;
+
+	    case 0x7: /* RESTORE.JRC[16] */
+	      if ((insn & 1) == 0 && (insn & 0x20) == 0x20)
+		return {}; /* Fall back to the standard single-step code. */
+	      break;
+
+	    case 0x26: /* BEQZC[16] */
+	    case 0x2e: /* BNEZC[16] */
+	      offset = ((insn & 1) << 6 | ((insn >> 1) & 0x3f)) << 1;
+	      offset = (offset ^ 0x80) - 0x80;
+	      branch_bp = loc + offset;
+	      is_branch = 1;
+	      break;
+
+	    case 0x36: /* P16.BR P16.JRC */
+	      offset = insn & 0xf;
+	      /* BEQC[16] BEQC[16] */
+	      if (offset != 0)
+		{
+		  branch_bp = loc + offset;
+		  is_branch = 1;
+		}
+	      else if (offset == 0) /* JALRC[16] JRC */
+		return {}; /* Fall back to the standard single-step code. */
+	      break;
+	    }
+	  break;
+	}
+
+      if (is_branch)
+	{
+	  if (last_breakpoint >= 1)
+	    return {}; /* More than one branch found, fallback to the
+			 standard single-step code.  */
+	  breaks[1] = branch_bp;
+	  last_breakpoint++;
+	}
+    }
+  if (!sc_found)
+    return {};
+
+  /* Insert a breakpoint right after the end of the atomic sequence.  */
+  breaks[0] = loc;
+
+  /* Check for duplicated breakpoints.  Check also for a breakpoint
+     placed (branch instruction's destination) in the atomic sequence */
+  if (last_breakpoint && pc <= breaks[1] && breaks[1] <= breaks[0])
+    last_breakpoint = 0;
+
+  std::vector<CORE_ADDR> next_pcs;
+
+  /* Effectively inserts the breakpoints.  */
+  for (index = 0; index <= last_breakpoint; index++)
+    next_pcs.push_back (breaks[index]);
+
+  return next_pcs;
+}
+
+/* nanomips_software_single_step() is called just before we want to resume
+   the inferior, if we want to single-step it but there is no hardware
+   or kernel single-step support (nanoMIPS on GNU/Linux for example).  We find
+   the target of the coming instruction and breakpoint it.  */
+
+std::vector<CORE_ADDR>
+nanomips_software_single_step (struct regcache *regcache)
+{
+  struct gdbarch *gdbarch = regcache->arch ();
+  CORE_ADDR pc, next_pc;
+
+  pc = regcache_read_pc (regcache);
+  std::vector<CORE_ADDR> next_pcs =
+			nanomips_deal_with_atomic_sequence (gdbarch, pc);
+
+  if (!next_pcs.empty ())
+    return next_pcs;
+
+  next_pc = nanomips_next_pc (regcache, pc);
+
+  return {next_pc};
+}
+
+/* This fencepost looks highly suspicious to me.  Removing it also
+   seems suspicious as it could affect remote debugging across serial
+   lines.  */
+
+static CORE_ADDR
+heuristic_proc_start (struct gdbarch *gdbarch, CORE_ADDR pc)
+{
+  CORE_ADDR start_pc;
+  CORE_ADDR fence;
+  int instlen;
+  struct inferior *inf;
+
+  pc = gdbarch_addr_bits_remove (gdbarch, pc);
+  start_pc = pc;
+  fence = start_pc - heuristic_fence_post;
+  if (start_pc == 0)
+    return 0;
+
+  if (heuristic_fence_post == -1 || fence < VM_MIN_ADDRESS)
+    fence = VM_MIN_ADDRESS;
+
+  instlen = INSN16_SIZE;
+
+  inf = current_inferior ();
+
+  /* Search back for previous return.  */
+  for (start_pc -= instlen;; start_pc -= instlen)
+    if (start_pc < fence)
+      {
+	/* It's not clear to me why we reach this point when
+	   stop_soon, but with this test, at least we
+	   don't print out warnings for every child forked (eg, on
+	   decstation).  22apr93 rich@cygnus.com.  */
+	if (inf->control.stop_soon == NO_STOP_QUIETLY)
+	  {
+	    static int blurb_printed = 0;
+
+	    warning (_("GDB can't find the start of the function at %s."),
+		     paddress (gdbarch, pc));
+
+	    if (!blurb_printed)
+	      {
+		/* This actually happens frequently in embedded
+		   development, when you first connect to a board
+		   and your stack pointer and pc are nowhere in
+		   particular.  This message needs to give people
+		   in that situation enough information to
+		   determine that it's no big deal.  */
+		gdb_printf ("\n\
+    GDB is unable to find the start of the function at %s\n\
+and thus can't determine the size of that function's stack frame.\n\
+This means that GDB may be unable to access that stack frame, or\n\
+the frames below it.\n\
+    This problem is most likely caused by an invalid program counter or\n\
+stack pointer.\n\
+    However, if you think GDB should simply search farther back\n\
+from %s for code which looks like the beginning of a\n\
+function, you can increase the range of the search using the `set\n\
+heuristic-fence-post' command.\n",
+			paddress (gdbarch, pc), paddress (gdbarch, pc));
+		blurb_printed = 1;
+	      }
+	  }
+
+	return 0;
+      }
+    else
+      {
+	ULONGEST insn;
+	int size;
+
+	/* On nanomips, SAVE is likely to be the start of a function.  */
+	insn = nanomips_fetch_instruction (gdbarch, pc, NULL);
+	size = nanomips_insn_size (insn);
+	if ((size == 2 && micromips_op (insn) == 0x7) ||
+	    (size == 4 && micromips_op (insn) == 0x20))
+	    break;
+      }
+
+  return start_pc;
+}
+
+/* On p32, argument passing in GPRs depends on the alignment of the type being
+   passed.  Return 1 if this type must be aligned to a doubleword boundary.  */
+
+static int
+type_needs_double_align (struct type *type)
+{
+  enum type_code typecode = type->code ();
+
+  if ((typecode == TYPE_CODE_FLT || typecode == TYPE_CODE_INT)
+      && type->length () == 8)
+    return 1;
+  else if (typecode == TYPE_CODE_STRUCT)
+    {
+      if (type->num_fields () > 1)
+	return 0;
+      return type_needs_double_align (type->field (0).type ());
+    }
+  else if (typecode == TYPE_CODE_UNION)
+    {
+      int i, n;
+
+      n = type->num_fields ();
+      for (i = 0; i < n; i++)
+	if (type_needs_double_align (type->field (i).type ()))
+	  return 1;
+      return 0;
+    }
+  return 0;
+}
+
+/* Adjust the address downward (direction of stack growth) so that it
+   is correctly aligned for a new stack frame.  */
+static CORE_ADDR
+nanomips_frame_align (struct gdbarch *gdbarch, CORE_ADDR addr)
+{
+  return align_down (addr, 16);
+}
+
+/* Implement the "push_dummy_code" gdbarch method.  */
+
+static CORE_ADDR
+nanomips_push_dummy_code (struct gdbarch *gdbarch, CORE_ADDR sp,
+			  CORE_ADDR funaddr, struct value **args,
+			  int nargs, struct type *value_type,
+			  CORE_ADDR *real_pc, CORE_ADDR *bp_addr,
+			  struct regcache *regcache)
+{
+  /* Reserve enough room on the stack for our breakpoint instruction.  */
+  sp = sp - 4;
+  *bp_addr = sp;
+
+  /* Inferior resumes at the function entry point.  */
+  *real_pc = funaddr;
+
+  return sp;
+}
+
+/* p32, p64 ABI stuff.  */
+
+#define MAX_REG_ARGS	8	/* Maximum 8 arguments in registers */
+
+static CORE_ADDR
+nanomips_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
+			  struct regcache *regcache, CORE_ADDR bp_addr,
+			  int nargs, struct value **args, CORE_ADDR sp,
+			  function_call_return_method return_method, CORE_ADDR struct_addr)
+{
+  int arg_gpr = 0, arg_fpr = 0;
+  int argnum;
+  int stack_offset = 0, stack_size = 0;
+  int seen_on_stack = 0;
+  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
+  int regsize = nanomips_abi_regsize (gdbarch);
+
+  /* Set the return address register to point to the entry point of
+     the program, where a breakpoint lies in wait.  */
+  regcache_cooked_write_signed (regcache, NANOMIPS_RA_REGNUM, bp_addr);
+
+  /* First ensure that the stack and structure return address (if any)
+     are properly aligned.  The stack has to be at least 64-bit
+     aligned even on 32-bit machines, because doubles must be 64-bit
+     aligned.  */
+
+  sp = align_down (sp, 16);
+  struct_addr = align_down (struct_addr, 16);
+
+  /* Calculate space required on the stack for the args.  */
+  for (argnum = 0; argnum < nargs; argnum++)
+    {
+      struct type *arg_type = check_typedef (value_type (args[argnum]));
+
+      /* Align to double-word if necessary.  */
+      if (type_needs_double_align (arg_type))
+	stack_size = align_up (stack_size, NANOMIPS32_REGSIZE * 2);
+
+      /* Allocate space on the stack.  */
+      stack_size += align_up (arg_type->length(), NANOMIPS32_REGSIZE);
+    }
+  stack_size = align_up (stack_size, 16);
+
+  if (nanomips_debug)
+    gdb_printf (gdb_stdlog, "nanomips_push_dummy_call (stack_size=%d)\n", stack_size);
+
+  /* The struct_return pointer occupies the first parameter-passing reg.  */
+  if (return_method == return_method_struct)
+    {
+      if (nanomips_debug)
+	gdb_printf (gdb_stdlog,
+			    "  struct_return reg=%d %s\n",
+			    arg_gpr + NANOMIPS_A0_REGNUM,
+			    paddress (gdbarch, struct_addr));
+
+      regcache_cooked_write_unsigned (regcache, arg_gpr + NANOMIPS_A0_REGNUM,
+				      struct_addr);
+
+      /* occupy first argument reg */
+      arg_gpr++;
+    }
+
+  /* Now load as many as possible of the first arguments into
+     registers, and push the rest onto the stack.  Loop thru args
+     from first to last.  */
+  for (argnum = 0; argnum < nargs; argnum++)
+    {
+      const gdb_byte *val;
+      gdb_byte valbuf[NANOMIPS64_REGSIZE];
+      struct value *arg = args[argnum];
+      struct type *arg_type = check_typedef (value_type (arg));
+      int len = arg_type->length();
+      enum type_code typecode = arg_type->code ();
+
+      if (typecode == TYPE_CODE_STRUCT && arg_type->num_fields () == 1)
+      {
+          if ((arg_type->field (0).type ())->code () == TYPE_CODE_TYPEDEF)
+            {
+              struct type *type = check_typedef (arg_type->field (0).type ());
+              typecode = type->code ();
+              len = arg_type->length();
+            }
+          else if ((arg_type->field (0).type ())->code () == TYPE_CODE_FLT)
+            {
+              typecode = TYPE_CODE_FLT;
+            }
+      }
+
+      /* The P32 ABI passes structures larger than 8 bytes by reference. */
+      if ((typecode == TYPE_CODE_ARRAY || typecode == TYPE_CODE_STRUCT
+          || typecode == TYPE_CODE_UNION || typecode == TYPE_CODE_COMPLEX)
+          && len > regsize * 2)
+        {
+          store_unsigned_integer (valbuf, regsize, byte_order,
+                value_address (arg));
+          typecode = TYPE_CODE_PTR;
+          len = 4;
+          val = valbuf;
+
+          if (nanomips_debug)
+            gdb_printf (gdb_stdlog, " push");
+        }
+          else
+        val = value_contents (arg).data ();
+
+
+      while (len > 0)
+	{
+	  int partial_len = (len < NANOMIPS32_REGSIZE ? len : NANOMIPS32_REGSIZE);
+	  LONGEST regval;
+	  int use_stack = 0;
+
+	  /* Align the argument register for double and long long types.  */
+	  if ((arg_gpr < MAX_REG_ARGS) && (arg_gpr & 1) && (len == 8)
+        && ((typecode == TYPE_CODE_FLT
+        && FPU_TYPE(gdbarch) == NANOMIPS_FPU_SOFT)
+        || typecode == TYPE_CODE_INT))
+	    {
+	      arg_gpr++;
+	      stack_offset += 4;
+	    }
+
+    if (typecode == TYPE_CODE_STRUCT && (len <= 8 && len > 4) && arg_gpr == 7)
+      arg_gpr ++;
+
+	  /* double type occupies only one register.  */
+	  if (typecode == TYPE_CODE_FLT && len == 8)
+	    partial_len = (FPU_TYPE(gdbarch) == NANOMIPS_FPU_HARD ? 8 : 4);
+
+	  regval = extract_unsigned_integer (val, partial_len, byte_order);
+
+	  /* Check if any argument register is available.  */
+	  if (typecode == TYPE_CODE_FLT && FPU_TYPE(gdbarch) == NANOMIPS_FPU_HARD)
+	    {
+        if(arg_fpr < MAX_REG_ARGS)
+          {
+            if (nanomips_debug)
+              {
+                int r_num = arg_fpr + nanomips_fp_arg_regnum (gdbarch)
+                  + gdbarch_num_regs (gdbarch);
+                const char *r = nanomips_register_name (gdbarch, r_num);
+                gdb_printf (gdb_stdlog,
+                        "  argnum=%d,reg=%s,len=%d,val=%ld\n",
+                        argnum + 1, r, partial_len, regval);
+              }
+
+           /* Update the register with specified value.  */
+           regcache_cooked_write_unsigned (regcache,
+                    arg_fpr + nanomips_fp_arg_regnum (gdbarch),
+                    regval);
+            arg_fpr++;
+          }
+        else
+          use_stack = 1;
+	    }
+	  else
+	    {
+		    if (arg_gpr < MAX_REG_ARGS)
+          {
+            if (nanomips_debug)
+              {
+                int r_num = arg_gpr + NANOMIPS_A0_REGNUM
+                  + gdbarch_num_regs (gdbarch);
+                const char *r = nanomips_register_name (gdbarch, r_num);
+                gdb_printf (gdb_stdlog,
+                        "  argnum=%d,reg=%s,len=%d,val=%ld\n",
+                        argnum + 1, r, partial_len, regval);
+              }
+
+            /* Update the register with specified value.  */
+            regcache_cooked_write_unsigned (regcache,
+                     arg_gpr + NANOMIPS_A0_REGNUM, regval);
+            arg_gpr++;
+
+	        }
+	      else
+	        use_stack = 1;
+
+	    }
+
+	  if (use_stack)
+	    {
+	      CORE_ADDR addr;
+
+	      if (nanomips_debug)
+		{
+		  LONGEST valreg = extract_unsigned_integer (val, len,
+							     byte_order);
+		  gdb_printf (gdb_stdlog,
+				      "  argnum=%d,off=%d,len=%d,val=%ld\n",
+				      argnum + 1, stack_offset, partial_len,
+				      valreg);
+		}
+
+	      addr = (sp - stack_size) + stack_offset;
+	      write_memory (addr, val, partial_len);
+
+	      seen_on_stack = 1;
+	      stack_offset += (partial_len <= NANOMIPS32_REGSIZE)
+                            ? NANOMIPS32_REGSIZE : partial_len;
+	      use_stack = 0;
+	    } /* argument on stack */
+
+	  val += partial_len;
+	  len -= partial_len;
+	}
+    }
+
+  if (seen_on_stack)
+    sp -= stack_size;
+
+  regcache_cooked_write_signed (regcache, NANOMIPS_SP_REGNUM, sp);
+
+  /* Return adjusted stack pointer.  */
+  return sp;
+}
+
+static enum return_value_convention
+nanomips_return_value (struct gdbarch *gdbarch, struct value *function,
+           struct type *type, struct regcache *regcache,
+           gdb_byte *readbuf, const gdb_byte *writebuf)
+{
+  if ((type->code () == TYPE_CODE_ARRAY
+      || type->code () == TYPE_CODE_STRUCT
+      || type->code () == TYPE_CODE_COMPLEX)
+      && type->length () > 2 * NANOMIPS32_REGSIZE)
+    return RETURN_VALUE_STRUCT_CONVENTION;
+
+  else if (type->code () == TYPE_CODE_COMPLEX
+     && FPU_TYPE(gdbarch) == NANOMIPS_FPU_HARD)
+    {
+      gdb_assert (nanomips_regnum (gdbarch)->fpr != -1);
+
+      nanomips_xfer_register (gdbarch, regcache,
+			      (gdbarch_num_regs (gdbarch)
+			       + nanomips_regnum (gdbarch)->fpr
+			       + NANOMIPS_FP0_REGNUM),
+			      4, gdbarch_byte_order (gdbarch),
+			      readbuf, writebuf, 0);
+      nanomips_xfer_register (gdbarch, regcache,
+			      (gdbarch_num_regs (gdbarch)
+			       + nanomips_regnum (gdbarch)->fpr
+			       + NANOMIPS_FP0_REGNUM + 1),
+			      4, gdbarch_byte_order (gdbarch),
+			      readbuf, writebuf, 4);
+      return RETURN_VALUE_REGISTER_CONVENTION;
+    }
+  else if (type->code () == TYPE_CODE_FLT
+     && FPU_TYPE(gdbarch) == NANOMIPS_FPU_HARD)
+    {
+      gdb_assert (nanomips_regnum (gdbarch)->fpr != -1);
+
+      nanomips_xfer_register (gdbarch, regcache,
+			      (gdbarch_num_regs (gdbarch)
+			       + nanomips_regnum (gdbarch)->fpr
+			       + NANOMIPS_FP0_REGNUM),
+			      type->length (), gdbarch_byte_order (gdbarch),
+			      readbuf, writebuf, 0);
+      return RETURN_VALUE_REGISTER_CONVENTION;
+    }
+  else
+    {
+      int offset;
+      int regnum;
+      for (offset = 0, regnum = NANOMIPS_A0_REGNUM;
+     offset < type->length ();
+     offset += NANOMIPS32_REGSIZE, regnum++)
+  {
+    int xfer = NANOMIPS32_REGSIZE;
+    if (offset + xfer > type->length ())
+      xfer = type->length () - offset;
+    if (nanomips_debug)
+      gdb_printf (gdb_stderr, "Return scalar+%d:%d in $%d\n",
+        offset, xfer, regnum);
+    nanomips_xfer_register (gdbarch, regcache,
+            gdbarch_num_regs (gdbarch) + regnum, xfer,
+            gdbarch_byte_order (gdbarch),
+            readbuf, writebuf, offset);
+  }
+      return RETURN_VALUE_REGISTER_CONVENTION;
+    }
+}
+
+/* Copy a 32-bit single-precision value from the current frame
+   into rare_buffer.  */
+
+static void
+read_fp_register_single (frame_info_ptr frame, int regno,
+			 gdb_byte *rare_buffer)
+{
+  struct gdbarch *gdbarch = get_frame_arch (frame);
+  int raw_size = register_size (gdbarch, regno);
+  int offset;
+  gdb_byte *raw_buffer = (gdb_byte *) alloca (raw_size);
+
+  if (!deprecated_frame_register_read (frame, regno, raw_buffer))
+    error (_("can't read register %d (%s)"),
+	   regno, gdbarch_register_name (gdbarch, regno));
+
+  /* We have a 64-bit value for this register.  Find the low-order 32 bits.  */
+  if (gdbarch_byte_order (gdbarch) == BFD_ENDIAN_BIG)
+    offset = 4;
+  else
+    offset = 0;
+
+  memcpy (rare_buffer, raw_buffer + offset, 4);
+}
+
+/* Copy a 64-bit double-precision value from the current frame into
+   rare_buffer.  */
+
+static void
+read_fp_register_double (frame_info_ptr frame, int regno,
+			 gdb_byte *rare_buffer)
+{
+  struct gdbarch *gdbarch = get_frame_arch (frame);
+
+  /* We have a 64-bit value for this register, use all 64 bits.  */
+  if (!deprecated_frame_register_read (frame, regno, rare_buffer))
+      error (_("can't read register %d (%s)"),
+	     regno, gdbarch_register_name (gdbarch, regno));
+}
+
+static void
+print_fp_register (struct ui_file *file, frame_info_ptr frame,
+		   int regnum)
+{		/* Do values for FP (float) regs.  */
+  struct gdbarch *gdbarch = get_frame_arch (frame);
+  gdb_byte *raw_buffer;
+  std::string flt_str, dbl_str;
+  struct value_print_options opts;
+
+  const struct type *flt_type = builtin_type (gdbarch)->builtin_float;
+  const struct type *dbl_type = builtin_type (gdbarch)->builtin_double;
+
+  gdb_assert (nanomips_regnum (gdbarch)->fpr != -1);
+
+  raw_buffer
+    = ((gdb_byte *)
+       alloca (2 * register_size (gdbarch,
+				  (nanomips_regnum (gdbarch)->fpr
+				   + NANOMIPS_FP0_REGNUM))));
+
+  gdb_printf (file, "%s:", gdbarch_register_name (gdbarch, regnum));
+  gdb_printf (file, "%*s",
+		    4 - (int) strlen (gdbarch_register_name (gdbarch, regnum)),
+		    "");
+
+  /* Eight byte registers: print each one as hex, float and double.  */
+  read_fp_register_single (frame, regnum, raw_buffer);
+  flt_str = target_float_to_string (raw_buffer, flt_type, "%-17.9g");
+
+  read_fp_register_double (frame, regnum, raw_buffer);
+  dbl_str = target_float_to_string (raw_buffer, dbl_type, "%-24.17g");
+
+  get_formatted_print_options (&opts, 'x');
+  print_scalar_formatted (raw_buffer,
+			  builtin_type (gdbarch)->builtin_uint64,
+			  &opts, 'g', file);
+
+  gdb_printf (file, " flt: %s", flt_str.c_str ());
+
+  gdb_printf (file, " dbl: %s", dbl_str.c_str ());
+}
+
+static void
+nanomips_print_register (struct ui_file *file, frame_info_ptr frame,
+			 int regnum)
+{
+  struct gdbarch *gdbarch = get_frame_arch (frame);
+  struct value_print_options opts;
+  struct value *val;
+
+  if (nanomips_float_register_p (gdbarch, regnum))
+    {
+      print_fp_register (file, frame, regnum);
+      return;
+    }
+
+  val = get_frame_register_value (frame, regnum);
+
+  gdb_puts (gdbarch_register_name (gdbarch, regnum), file);
+
+  /* The problem with printing numeric register names (r26, etc.) is that
+     the user can't use them on input.  Probably the best solution is to
+     fix it so that either the numeric or the funky (a2, etc.) names
+     are accepted on input.  */
+  if (regnum < NUMREGS)
+    gdb_printf (file, "(r%d): ", regnum);
+  else
+    gdb_printf (file, ": ");
+
+  get_formatted_print_options (&opts, 'x');
+  value_print_scalar_formatted (val, &opts, 0, file);
+}
+
+/* Print IEEE exception condition bits in FLAGS.  */
+
+static void
+print_fpu_flags (struct ui_file *file, int flags)
+{
+  if (flags & (1 << 0))
+    gdb_puts (" inexact", file);
+  if (flags & (1 << 1))
+    gdb_puts (" uflow", file);
+  if (flags & (1 << 2))
+    gdb_puts (" oflow", file);
+  if (flags & (1 << 3))
+    gdb_puts (" div0", file);
+  if (flags & (1 << 4))
+    gdb_puts (" inval", file);
+  if (flags & (1 << 5))
+    gdb_puts (" unimp", file);
+  gdb_putc ('\n', file);
+}
+
+/* Print interesting information about the floating point processor
+   (if present) or emulator.  */
+
+static void
+nanomips_print_float_info (struct gdbarch *gdbarch, struct ui_file *file,
+			   frame_info_ptr frame, const char *args)
+{
+  int fcsr = nanomips_regnum (gdbarch)->fpr + NANOMIPS_FCSR_REGNUM;
+  enum fpu_type type = FPU_TYPE (gdbarch);
+  ULONGEST fcs = 0;
+  int i;
+
+  if (nanomips_regnum (gdbarch)->fpr == -1
+      || !read_frame_register_unsigned (frame, fcsr, &fcs))
+    type = NANOMIPS_FPU_NONE;
+
+  gdb_printf (file, "fpu type: %s\n",
+		    type == NANOMIPS_FPU_HARD ? "64bit hardware floating point"
+		    : type == NANOMIPS_FPU_SOFT ? "Software floating point"
+		    : "none / unused");
+
+  if (type == NANOMIPS_FPU_NONE)
+    return;
+
+  gdb_printf (file, "reg size: %d bits\n",
+		    register_size (gdbarch,
+				   (nanomips_regnum (gdbarch)->fpr
+				    + NANOMIPS_FP0_REGNUM)) * 8);
+
+  gdb_puts ("cond    :", file);
+  if (fcs & (1 << 23))
+    gdb_puts (" 0", file);
+  for (i = 1; i <= 7; i++)
+    if (fcs & (1 << (24 + i)))
+      gdb_printf (file, " %d", i);
+  gdb_putc ('\n', file);
+
+  gdb_puts ("cause   :", file);
+  print_fpu_flags (file, (fcs >> 12) & 0x3f);
+  fputs ("mask    :", stdout);
+  print_fpu_flags (file, (fcs >> 7) & 0x1f);
+  fputs ("flags   :", stdout);
+  print_fpu_flags (file, (fcs >> 2) & 0x1f);
+
+  gdb_puts ("rounding: ", file);
+  switch (fcs & 3)
+    {
+    case 0: gdb_puts ("nearest\n", file); break;
+    case 1: gdb_puts ("zero\n", file); break;
+    case 2: gdb_puts ("+inf\n", file); break;
+    case 3: gdb_puts ("-inf\n", file); break;
+    }
+
+  gdb_puts ("flush   :", file);
+  if (fcs & (1 << 21))
+    gdb_puts (" nearest", file);
+  if (fcs & (1 << 22))
+    gdb_puts (" override", file);
+  if (fcs & (1 << 24))
+    gdb_puts (" zero", file);
+  if ((fcs & (0xb << 21)) == 0)
+    gdb_puts (" no", file);
+  gdb_putc ('\n', file);
+
+  gdb_printf (file, "nan2008 : %s\n", fcs & (1 << 18) ? "yes" : "no");
+  gdb_printf (file, "abs2008 : %s\n", fcs & (1 << 19) ? "yes" : "no");
+  gdb_putc ('\n', file);
+
+  default_print_float_info (gdbarch, file, frame, args);
+}
+
+/* Replacement for generic do_registers_info.
+   Print regs in pretty columns.  */
+
+static int
+print_fp_register_row (struct ui_file *file, frame_info_ptr frame,
+		       int regnum)
+{
+  gdb_printf (file, " ");
+  print_fp_register (file, frame, regnum);
+  gdb_printf (file, "\n");
+  return regnum + 1;
+}
+
+
+/* Print a row's worth of GP (int) registers, with name labels above.  */
+
+static int
+print_gp_register_row (struct ui_file *file, frame_info_ptr frame,
+		       int start_regnum)
+{
+  struct gdbarch *gdbarch = get_frame_arch (frame);
+  /* Do values for GP (int) regs.  */
+  gdb_byte raw_buffer[NANOMIPS64_REGSIZE];
+  int ncols = (nanomips_abi_regsize (gdbarch) == 8 ? 4 : 8);    /* display cols
+							       per row.  */
+  int col, byte;
+  int regnum;
+
+  /* For GP registers, we print a separate row of names above the vals.  */
+  for (col = 0, regnum = start_regnum;
+       col < ncols && regnum < gdbarch_num_regs (gdbarch)
+			       + gdbarch_num_pseudo_regs (gdbarch);
+       regnum++)
+    {
+      if (*gdbarch_register_name (gdbarch, regnum) == '\0')
+	continue;		/* unused register */
+      if (nanomips_float_register_p (gdbarch, regnum))
+	break;			/* End the row: reached FP register.  */
+      /* Large registers are handled separately.  */
+      if (register_size (gdbarch, regnum) > nanomips_abi_regsize (gdbarch))
+	{
+	  if (col > 0)
+	    break;		/* End the row before this register.  */
+
+	  /* Print this register on a row by itself.  */
+	  nanomips_print_register (file, frame, regnum);
+	  gdb_printf (file, "\n");
+	  return regnum + 1;
+	}
+      if (col == 0)
+	gdb_printf (file, "     ");
+      gdb_printf (file,
+			nanomips_abi_regsize (gdbarch) == 8 ? "%17s" : "%9s",
+			gdbarch_register_name (gdbarch, regnum));
+      col++;
+    }
+
+  if (col == 0)
+    return regnum;
+
+  /* Print the R0 to R31 names.  */
+  if ((start_regnum % gdbarch_num_regs (gdbarch)) < NUMREGS)
+    gdb_printf (file, "\n R%-4d",
+		      start_regnum % gdbarch_num_regs (gdbarch));
+  else
+    gdb_printf (file, "\n      ");
+
+  /* Now print the values in hex, 4 or 8 to the row.  */
+  for (col = 0, regnum = start_regnum;
+       col < ncols && regnum < gdbarch_num_regs (gdbarch)
+			       + gdbarch_num_pseudo_regs (gdbarch);
+       regnum++)
+    {
+      if (*gdbarch_register_name (gdbarch, regnum) == '\0')
+	continue;		/* unused register */
+      if (nanomips_float_register_p (gdbarch, regnum))
+	break;			/* End row: reached FP register.  */
+      if (register_size (gdbarch, regnum) > nanomips_abi_regsize (gdbarch))
+	break;			/* End row: large register.  */
+
+      /* OK: get the data in raw format.  */
+      if (!deprecated_frame_register_read (frame, regnum, raw_buffer))
+	error (_("can't read register %d (%s)"),
+	       regnum, gdbarch_register_name (gdbarch, regnum));
+      /* pad small registers */
+      for (byte = 0;
+	   byte < (nanomips_abi_regsize (gdbarch)
+		   - register_size (gdbarch, regnum)); byte++)
+	gdb_printf ("  ");
+      /* Now print the register value in hex, endian order.  */
+      if (gdbarch_byte_order (gdbarch) == BFD_ENDIAN_BIG)
+	for (byte =
+	     register_size (gdbarch, regnum) - register_size (gdbarch, regnum);
+	     byte < register_size (gdbarch, regnum); byte++)
+	  gdb_printf (file, "%02x", raw_buffer[byte]);
+      else
+	for (byte = register_size (gdbarch, regnum) - 1;
+	     byte >= 0; byte--)
+	  gdb_printf (file, "%02x", raw_buffer[byte]);
+      gdb_printf (file, " ");
+      col++;
+    }
+  if (col > 0)			/* ie. if we actually printed anything...  */
+    gdb_printf (file, "\n");
+
+  return regnum;
+}
+
+/* MIPS_DO_REGISTERS_INFO(): called by "info register" command.  */
+
+static void
+nanomips_print_registers_info (struct gdbarch *gdbarch, struct ui_file *file,
+			       frame_info_ptr frame, int regnum, int all)
+{
+  if (regnum != -1)		/* Do one specified register.  */
+    {
+      gdb_assert (regnum >= gdbarch_num_regs (gdbarch));
+      if (*(gdbarch_register_name (gdbarch, regnum)) == '\0')
+	error (_("Not a valid register for the current processor type"));
+
+      nanomips_print_register (file, frame, regnum);
+      gdb_printf (file, "\n");
+    }
+  else
+    /* Do all (or most) registers.  */
+    {
+      regnum = gdbarch_num_regs (gdbarch);
+      while (regnum < gdbarch_num_regs (gdbarch)
+		      + gdbarch_num_pseudo_regs (gdbarch))
+	{
+	  if (nanomips_float_register_p (gdbarch, regnum))
+	    {
+	      if (all)		/* True for "INFO ALL-REGISTERS" command.  */
+		regnum = print_fp_register_row (file, frame, regnum);
+	      else
+		regnum += NUMREGS;	/* Skip floating point regs.  */
+	    }
+	  else
+	    regnum = print_gp_register_row (file, frame, regnum);
+	}
+    }
+}
+
+/* To skip prologues, I use this predicate.  Returns either PC itself
+   if the code at PC does not look like a function prologue; otherwise
+   returns an address that (if we're lucky) follows the prologue.  If
+   LENIENT, then we must skip everything which is involved in setting
+   up the frame (it's OK to skip more, just so long as we don't skip
+   anything which might clobber the registers which are being saved.
+   We must skip more in the case where part of the prologue is in the
+   delay slot of a non-prologue instruction).  */
+
+static CORE_ADDR
+nanomips_skip_prologue (struct gdbarch *gdbarch, CORE_ADDR pc)
+{
+  CORE_ADDR limit_pc;
+  CORE_ADDR func_addr;
+
+  /* See if we can determine the end of the prologue via the symbol table.
+     If so, then return either PC, or the PC after the prologue, whichever
+     is greater.  */
+  if (find_pc_partial_function (pc, NULL, &func_addr, NULL))
+    {
+      CORE_ADDR post_prologue_pc
+	= skip_prologue_using_sal (gdbarch, func_addr);
+      if (post_prologue_pc != 0)
+	return std::max (pc, post_prologue_pc);
+    }
+
+  /* Can't determine prologue from the symbol table, need to examine
+     instructions.  */
+
+  /* Find an upper limit on the function prologue using the debug
+     information.  If the debug information could not be used to provide
+     that bound, then use an arbitrary large number as the upper bound.  */
+  limit_pc = skip_prologue_using_sal (gdbarch, pc);
+  if (limit_pc == 0)
+    limit_pc = pc + 100;          /* Magic.  */
+
+  return nanomips_scan_prologue (gdbarch, pc, limit_pc, NULL, NULL);
+}
+
+/* Implement the stack_frame_destroyed_p gdbarch method (nanoMIPS version).
+   This is a helper function for mips_stack_frame_destroyed_p.  */
+
+static int
+nanomips_stack_frame_destroyed_p (struct gdbarch *gdbarch, CORE_ADDR pc)
+{
+  CORE_ADDR func_addr = 0;
+  CORE_ADDR func_end = 0;
+  CORE_ADDR addr;
+  ULONGEST insn;
+  int dreg;
+  int sreg;
+  int treg, op;
+  int loc;
+
+  if (!find_pc_partial_function (pc, NULL, &func_addr, &func_end))
+    return 0;
+
+  /* The nanoMIPS epilogue is max. 12 bytes long.  */
+  addr = func_end - 12;
+
+  if (addr < func_addr + 2)
+    addr = func_addr + 2;
+  if (pc < addr)
+    return 0;
+
+  for (; pc < func_end; pc += loc)
+    {
+      loc = 0;
+      insn = nanomips_fetch_instruction (gdbarch, pc, NULL);
+      loc += INSN16_SIZE;
+      switch (nanomips_insn_size (insn))
+	{
+	/* 48-bit instructions.  */
+	case 3 * INSN16_SIZE:
+	  if (micromips_op (insn) == 0x18)
+	    {
+	      op = b0s5_imm (insn);
+	      treg = b5s5_reg (insn);
+	      if (op == 0x0) /* LI48 xx, imm32 */
+		break; /* continue scan */
+	      else if (op == 0x1 /* ADDIU48 $sp, imm32 */
+		       && treg == NANOMIPS_SP_REGNUM)
+		return 1;
+	    }
+	  return 0;
+
+	/* 32-bit instructions.  */
+	case 2 * INSN16_SIZE:
+	  insn <<= 16;
+	  insn |= nanomips_fetch_instruction (gdbarch, pc + loc, NULL);
+	  loc += INSN16_SIZE;
+
+	  switch (micromips_op (insn >> 16))
+	    {
+	    case 0x0: /* PP.ADDIU bits 000000 */
+	      treg = b5s5_reg (insn >> 16);
+	      sreg = b0s5_reg (insn >> 16);
+	      if (sreg == treg
+		  && treg == NANOMIPS_SP_REGNUM) /* ADDIU $sp, $sp, imm */
+		return 1;
+	      else if (sreg == NANOMIPS_SP_REGNUM && treg == 30)
+		break; /* continue scan */
+	      return 0;
+
+	    case 0x8: /* _POOL32A0 */
+	      if ((insn & 0x1ff) == 0x150) /* ADDU */
+		{
+		  dreg = b11s5_reg (insn);
+		  sreg = b0s5_reg (insn >> 16);
+		  if ((dreg == sreg && sreg == NANOMIPS_SP_REGNUM)
+		      /* ADDU $sp, $sp, xx */
+		      || (dreg == NANOMIPS_SP_REGNUM && sreg == 30))
+		      /* ADDU $sp, $fp, xx */
+		    break; /* continue scan */
+		}
+	      else if (((insn & 0xffff) == 0xE37F) /* DERET */
+		       || ((insn & 0x1ffff) == 0xF37F) /* ERET */
+		       || ((insn & 0x1ffff) == 0x1F37F)) /* ERETNC */
+		return 1;
+	      return 0;
+
+	    case 0x20: /* P.U12 bits 100000 */
+	      if (b12s4_op (insn) == 0) /* ORI: bits 100000 0000 */
+		{
+		  sreg = b0s5_reg (insn >> 16);
+		  treg = b5s5_reg (insn >> 16);
+		  if (sreg == treg && treg == 3) /* ORI $v1, $v1, imm */
+		    break; /* continue scan */
+		}
+	      else if (b12s5_op (insn) == 0x13) /* RESTORE, RESTORE.JRC */
+		return 1;
+	      return 0;
+
+	    case 0x38: /* P.LUI bits 111000 */
+	      treg = b5s5_reg (insn >> 16);
+	      if ((insn & 2) == 0 /* LU20I bits 111000 0 */
+		  && treg == 3) /* LU20I $v1, imm */
+		break; /* continue scan */
+	      return 0;
+
+	    default:
+	      return 0;
+	    }
+	  break;
+
+	/* 16-bit instructions.  */
+	case INSN16_SIZE:
+	  switch (micromips_op (insn))
+	    {
+	    case 0x4: /* MOVE: bits 000100 */
+	      sreg = b0s5_reg (insn);
+	      dreg = b5s5_reg (insn);
+	      if (sreg == NANOMIPS_SP_REGNUM && dreg == 30)
+			/* MOVE  $fp, $sp */
+		return 1;
+	      return 0;
+
+	    case 0x7: /* RESTORE[16], RESTORE.JRC[16] */
+	      if ((insn & 0x20) == 0x20)
+		return 1;
+	      return 0;
+
+	    case 0x36: /* JRC[16] $31 */
+	      if ((insn & 0x1f) == 0 && b5s5_reg (insn) == 31)
+		return 1;
+	      return 0;
+
+	    default:
+		return 0;
+	    }
+	  break;
+	}
+    }
+
+  return 1;
+}
+
+/* Root of all "set nanomips "/"show nanomips " commands.  This will eventually be
+   used for all nanoMIPS-specific commands.  */
+
+static void
+show_nanomips_command (const char *args, int from_tty)
+{
+  help_list (shownanomipscmdlist, "show nanomips ", all_commands, gdb_stdout);
+}
+
+static void
+set_nanomips_command (const char *args, int from_tty)
+{
+  printf_unfiltered
+    ("\"set nanomips\" must be followed by an appropriate subcommand.\n");
+  help_list (setnanomipscmdlist, "set nanomips ", all_commands, gdb_stdout);
+}
+
+/* Just like reinit_frame_cache, but with the right arguments to be
+   callable as an sfunc.  */
+
+static void
+reinit_frame_cache_sfunc (const char *args, int from_tty,
+			  struct cmd_list_element *c)
+{
+  reinit_frame_cache ();
+}
+
+static int
+gdb_print_insn_nanomips_p32 (bfd_vma memaddr, struct disassemble_info *info)
+{
+  info->mach = bfd_mach_nanomipsisa32r6;
+  info->flavour = bfd_target_elf_flavour;
+  info->disassembler_options = "gpr-names=p32";
+
+  return print_insn_nanomips (memaddr, info);
+}
+
+static int
+gdb_print_insn_nanomips_p64 (bfd_vma memaddr, struct disassemble_info *info)
+{
+  info->mach = bfd_mach_nanomipsisa64r6;
+  info->flavour = bfd_target_elf_flavour;
+  info->disassembler_options = "gpr-names=p64";
+
+  return print_insn_nanomips (memaddr, info);
+}
+
+/* Implement the breakpoint_kind_from_pc gdbarch method.  */
+
+static int
+nanomips_breakpoint_kind_from_pc (struct gdbarch *gdbarch, CORE_ADDR *pcptr)
+{
+  CORE_ADDR pc = *pcptr;
+  ULONGEST insn;
+  int status;
+
+  insn = nanomips_fetch_instruction (gdbarch, pc, &status);
+  if (status || (nanomips_insn_size (insn) == 2))
+    return NANOMIPS_BP_KIND_16;
+  else
+    return NANOMIPS_BP_KIND_32;
+}
+
+/* Implement the sw_breakpoint_from_kind gdbarch method.  */
+
+static const gdb_byte *
+nanomips_sw_breakpoint_from_kind (struct gdbarch *gdbarch, int kind, int *size)
+{
+  enum bfd_endian byte_order_for_code = gdbarch_byte_order_for_code (gdbarch);
+
+  switch (kind)
+    {
+    case NANOMIPS_BP_KIND_16:
+      {
+	static gdb_byte be16_break[] = { 0x10, 0x10 };
+	static gdb_byte le16_break[] = { 0x10, 0x10 };
+
+	*size = 2;
+
+	if (byte_order_for_code == BFD_ENDIAN_BIG)
+	  return be16_break;
+	else
+	  return le16_break;
+      }
+    case NANOMIPS_BP_KIND_32:
+      {
+	static gdb_byte be32_break[] = { 0, 0x10, 0, 0 };
+	static gdb_byte le32_break[] = { 0x10, 0, 0, 0 };
+
+	*size = 4;
+	if (byte_order_for_code == BFD_ENDIAN_BIG)
+	  return be32_break;
+	else
+	  return le32_break;
+      }
+    default:
+      gdb_assert_not_reached ("unexpected nanomips breakpoint kind");
+    };
+}
+
+/* Convert a dbx stab register number (from `r' declaration) to a GDB
+   [1 * gdbarch_num_regs .. 2 * gdbarch_num_regs) REGNUM.  */
+
+static int
+nanomips_stab_reg_to_regnum (struct gdbarch *gdbarch, int num)
+{
+  int regnum;
+  if (num >= 0 && num < 32)
+    regnum = num;
+  else if (nanomips_regnum (gdbarch)->fpr != -1 && num >= 36 && num < 70)
+    regnum = num + nanomips_regnum (gdbarch)->fpr + NANOMIPS_FP0_REGNUM - 36;
+  else if (nanomips_regnum (gdbarch)->dsp != -1 && num >= 70 && num < 78)
+    regnum
+      = num + nanomips_regnum (gdbarch)->dsp + NANOMIPS_DSPHI0_REGNUM - 70;
+  else
+    return -1;
+  return gdbarch_num_regs (gdbarch) + regnum;
+}
+
+
+/* Convert a dwarf, dwarf2, or ecoff register number to a GDB [1 *
+   gdbarch_num_regs .. 2 * gdbarch_num_regs) REGNUM.  */
+
+static int
+nanomips_dwarf_dwarf2_ecoff_reg_to_regnum (struct gdbarch *gdbarch, int num)
+{
+  int regnum;
+  if (num >= 0 && num < 32)
+    regnum = num;
+  else if (nanomips_regnum (gdbarch)->fpr != -1 && num >= 32 && num < 64)
+    regnum = num + nanomips_regnum (gdbarch)->fpr + NANOMIPS_FP0_REGNUM - 32;
+  else if (nanomips_regnum (gdbarch)->dsp != -1 && num >= 64 && num < 72)
+    regnum
+      = num + nanomips_regnum (gdbarch)->dsp + NANOMIPS_DSPHI0_REGNUM - 64;
+  else
+    return -1;
+  return gdbarch_num_regs (gdbarch) + regnum;
+}
+
+static int
+nanomips_register_sim_regno (struct gdbarch *gdbarch, int regnum)
+{
+  /* Only makes sense to supply raw registers.  */
+  gdb_assert (regnum >= 0 && regnum < gdbarch_num_regs (gdbarch));
+  /* FIXME: cagney/2002-05-13: Need to look at the pseudo register to
+     decide if it is valid.  Should instead define a standard sim/gdb
+     register numbering scheme.  */
+  if (gdbarch_register_name (gdbarch,
+			     gdbarch_num_regs (gdbarch) + regnum) != NULL
+      && gdbarch_register_name (gdbarch,
+			        gdbarch_num_regs (gdbarch)
+				+ regnum)[0] != '\0')
+    return regnum;
+  else
+    return LEGACY_SIM_REGNO_IGNORE;
+}
+
+
+/* Convert an integer into an address.  Extracting the value signed
+   guarantees a correctly sign extended address.  */
+
+static CORE_ADDR
+nanomips_integer_to_address (struct gdbarch *gdbarch,
+			     struct type *type, const gdb_byte *buf)
+{
+  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
+  return extract_signed_integer (buf, type->length (), byte_order);
+}
+
+/* Dummy virtual frame pointer method.  This is no more or less accurate
+   than most other architectures; we just need to be explicit about it,
+   because the pseudo-register gdbarch_sp_regnum will otherwise lead to
+   an assertion failure.  */
+
+static void
+nanomips_virtual_frame_pointer (struct gdbarch *gdbarch,
+				CORE_ADDR pc, int *reg, LONGEST *offset)
+{
+  *reg = NANOMIPS_SP_REGNUM;
+  *offset = 0;
+}
+
+static struct gdbarch *
+nanomips_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
+{
+  static const char *const mips_gprs[] = {
+    "r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7",
+    "r8", "r9", "r10", "r11", "r12", "r13", "r14", "r15",
+    "r16", "r17", "r18", "r19", "r20", "r21", "r22", "r23",
+    "r24", "r25", "r26", "r27", "r28", "r29", "r30", "r31"
+  };
+  static const char *const mips_fprs[] = {
+    "f0", "f1", "f2", "f3", "f4", "f5", "f6", "f7",
+    "f8", "f9", "f10", "f11", "f12", "f13", "f14", "f15",
+    "f16", "f17", "f18", "f19", "f20", "f21", "f22", "f23",
+    "f24", "f25", "f26", "f27", "f28", "f29", "f30", "f31"
+  };
+  static const char *const mips_dsprs[] = {
+    "hi0", "lo0", "hi1", "lo1", "hi2", "lo2", "hi3", "lo3"
+  };
+  const struct tdesc_feature *feature;
+  struct gdbarch *gdbarch;
+  struct nanomips_gdbarch_tdep *tdep;
+  int elf_flags;
+  enum nanomips_abi nanomips_abi, found_abi;
+  int i, num_regs;
+  enum fpu_type fpu_type;
+  tdesc_arch_data_up tdesc_data;
+  const struct target_desc *tdesc = info.target_desc;
+  int elf_fpu_type = Val_GNU_NANOMIPS_ABI_FP_ANY;
+  struct nanomips_regnum nanomips_regnum, *regnum;
+  int register_size;
+  int valid_p;
+
+  num_regs = 0;
+
+  nanomips_regnum.cause = -1;
+  nanomips_regnum.status = -1;
+  nanomips_regnum.badvaddr = -1;
+  nanomips_regnum.fpr = -1;
+  nanomips_regnum.dsp = -1;
+  nanomips_regnum.restart = -1;
+
+  /* If there's no target description, then use the default.  */
+  if (!tdesc_has_registers (tdesc))
+    tdesc = tdesc_nanomips;
+
+  /* The CPU feature and the registers within are mandatory.  */
+  feature = tdesc_find_feature (tdesc, "org.gnu.gdb.nanomips.cpu");
+  if (feature == NULL)
+    return NULL;
+
+  tdesc_data = tdesc_data_alloc ();
+
+  valid_p = 1;
+  for (i = 0; i < 32; i++, num_regs++)
+    valid_p &= tdesc_numbered_register (feature, tdesc_data.get (), num_regs,
+					mips_gprs[i]);
+  valid_p &= tdesc_numbered_register (feature, tdesc_data.get (), num_regs++, "pc");
+  if (!valid_p)
+      return NULL;
+  register_size = tdesc_register_bitsize (feature, "r0") / 8;
+
+  /* All the remaining target description features are optional.  */
+
+  /* Check for and assign a number to the syscall restart PC register.  */
+  feature = tdesc_find_feature (tdesc, "org.gnu.gdb.nanomips.linux");
+  if (feature != NULL)
+    {
+      if (tdesc_numbered_register (feature, tdesc_data.get (), num_regs, "restart"))
+	nanomips_regnum.restart = num_regs++;
+
+      /* Check for and assign numbers to particular CP0 registers.
+	 These are only special and need known numbers with Linux
+	 targets, due to the use in signal frames, etc.  Bare metal
+	 stubs can simply include them along with other CP0 registers.  */
+      feature = tdesc_find_feature (tdesc, "org.gnu.gdb.nanomips.cp0");
+      if (feature != NULL)
+	{
+	  if (tdesc_numbered_register (feature, tdesc_data.get (), num_regs,
+				       "badvaddr"))
+	    nanomips_regnum.badvaddr = num_regs++;
+	  if (tdesc_numbered_register (feature, tdesc_data.get (), num_regs,
+				       "status"))
+	    nanomips_regnum.status = num_regs++;
+	  if (tdesc_numbered_register (feature, tdesc_data.get (), num_regs,
+				       "cause"))
+	    nanomips_regnum.cause = num_regs++;
+	}
+    }
+
+  /* Check for and assign numbers to FPU registers.  */
+  feature = tdesc_find_feature (tdesc, "org.gnu.gdb.nanomips.fpu");
+  if (feature != NULL)
+    {
+      nanomips_regnum.fpr = num_regs;
+      for (i = 0; i < 32; i++, num_regs++)
+	valid_p &= tdesc_numbered_register (feature, tdesc_data.get (), num_regs,
+					    mips_fprs[i]);
+      valid_p &= tdesc_numbered_register (feature, tdesc_data.get (), num_regs++,
+					  "fcsr");
+      valid_p &= tdesc_numbered_register (feature, tdesc_data.get (), num_regs++,
+					  "fir");
+      if (!valid_p)
+      return NULL;
+    }
+
+  /* Check for and assign numbers to DSP registers.  */
+  feature = tdesc_find_feature (tdesc, "org.gnu.gdb.nanomips.dsp");
+  if (feature != NULL)
+    {
+      nanomips_regnum.dsp = num_regs;
+      for (i = 0; i < 8; i++, num_regs++)
+	valid_p &= tdesc_numbered_register (feature, tdesc_data.get (), num_regs,
+					    mips_dsprs[i]);
+      valid_p &= tdesc_numbered_register (feature, tdesc_data.get (), num_regs++,
+					  "dspctl");
+      if (!valid_p)
+        return NULL;
+    }
+
+  /* First of all, extract the elf_flags, if available.  */
+  if (info.abfd && bfd_get_flavour (info.abfd) == bfd_target_elf_flavour)
+    elf_flags = elf_elfheader (info.abfd)->e_flags;
+  else if (arches != NULL)
+    elf_flags = (gdbarch_tdep<nanomips_gdbarch_tdep> (arches->gdbarch))->elf_flags;
+  else
+    elf_flags = 0;
+
+  if (gdbarch_debug)
+    gdb_printf (gdb_stdlog,
+			"nanomips_gdbarch_init: elf_flags = 0x%08x\n",
+			elf_flags);
+
+  /* Check ELF_FLAGS to see if it specifies the ABI being used.  */
+  switch ((elf_flags & EF_NANOMIPS_ABI))
+    {
+    case E_NANOMIPS_ABI_P32:
+      found_abi = NANOMIPS_ABI_P32;
+      break;
+    case E_NANOMIPS_ABI_P64:
+      found_abi = NANOMIPS_ABI_P64;
+      break;
+    default:
+      found_abi = NANOMIPS_ABI_UNKNOWN;
+      break;
+    }
+
+  /* If we have no useful BFD information, use the ABI from the last
+     nanoMIPS architecture (if there is one).  */
+  if (found_abi == NANOMIPS_ABI_UNKNOWN && info.abfd == NULL && arches != NULL)
+    found_abi = (gdbarch_tdep<nanomips_gdbarch_tdep> (arches->gdbarch))->found_abi;
+
+  /* Try the architecture for any hint of the correct ABI.  */
+  if (found_abi == NANOMIPS_ABI_UNKNOWN
+      && info.bfd_arch_info != NULL
+      && info.bfd_arch_info->arch == bfd_arch_nanomips)
+    {
+      switch (info.bfd_arch_info->mach)
+	{
+	case bfd_mach_nanomipsisa32r6:
+	  found_abi = NANOMIPS_ABI_P32;
+	  break;
+	case bfd_mach_nanomipsisa64r6:
+	  found_abi = NANOMIPS_ABI_P64;
+	  break;
+	}
+    }
+
+  /* Default 64-bit objects to P64 instead of P32.  */
+  if (found_abi == NANOMIPS_ABI_UNKNOWN
+      && info.abfd != NULL
+      && bfd_get_flavour (info.abfd) == bfd_target_elf_flavour
+      && elf_elfheader (info.abfd)->e_ident[EI_CLASS] == ELFCLASS64)
+    found_abi = NANOMIPS_ABI_P64;
+
+  if (gdbarch_debug)
+    gdb_printf (gdb_stdlog, "nanomips_gdbarch_init: found_abi = %d\n",
+			found_abi);
+
+  /* Now that we have found what the ABI for this binary would be,
+     check whether the user is overriding it.  */
+  if (found_abi != NANOMIPS_ABI_UNKNOWN)
+    nanomips_abi = found_abi;
+  else
+    nanomips_abi = NANOMIPS_ABI_P32;
+  if (gdbarch_debug)
+    gdb_printf (gdb_stdlog,
+			"nanomips_gdbarch_init: nanomips_abi = %d\n",
+			nanomips_abi);
+
+  /* Determine the nanoMIPS FPU type.  */
+  if (info.abfd
+      && bfd_get_flavour (info.abfd) == bfd_target_elf_flavour)
+    {
+      Elf_Internal_ABIFlags_v0 *abiflags;
+      abiflags = bfd_nanomips_elf_get_abiflags (info.abfd);
+      if (abiflags != NULL)
+	elf_fpu_type = abiflags->fp_abi;
+    }
+
+  if (elf_fpu_type != Val_GNU_NANOMIPS_ABI_FP_ANY)
+    {
+      switch (elf_fpu_type)
+	{
+	case Val_GNU_NANOMIPS_ABI_FP_SOFT:
+	  fpu_type = NANOMIPS_FPU_SOFT;
+	  break;
+	default:
+	  fpu_type = NANOMIPS_FPU_HARD;
+	  break;
+	}
+    }
+  else if (arches != NULL)
+    fpu_type = (gdbarch_tdep<nanomips_gdbarch_tdep> (arches->gdbarch))->fpu_type;
+  else
+    fpu_type = NANOMIPS_FPU_HARD;
+
+  if (gdbarch_debug)
+    gdb_printf (gdb_stdlog,
+			"nanomips_gdbarch_init: fpu_type = %d\n", fpu_type);
+
+  /* Check for blatant incompatibilities.  */
+
+  /* If we have only 32-bit registers, then we can't debug a 64-bit ABI.  */
+  if (register_size == 4 && nanomips_abi != NANOMIPS_ABI_P32)
+    {
+      return NULL;
+    }
+
+  /* Try to find a pre-existing architecture.  */
+  for (arches = gdbarch_list_lookup_by_info (arches, &info);
+       arches != NULL;
+       arches = gdbarch_list_lookup_by_info (arches->next, &info))
+    {
+      /* nanoMIPS needs to be pedantic about which ABI and the compressed
+         ISA variation the object is using.  */
+      if (gdbarch_tdep<nanomips_gdbarch_tdep> (arches->gdbarch)->elf_flags != elf_flags)
+	continue;
+      if (gdbarch_tdep<nanomips_gdbarch_tdep> (arches->gdbarch)->nanomips_abi != nanomips_abi)
+	continue;
+      /* Be pedantic about which FPU is selected.  */
+      if (gdbarch_tdep<nanomips_gdbarch_tdep> (arches->gdbarch)->fpu_type != fpu_type)
+	continue;
+
+      return arches->gdbarch;
+    }
+
+  /* Need a new architecture.  Fill in a target specific vector.  */
+  tdep = new (struct nanomips_gdbarch_tdep);
+  gdbarch = gdbarch_alloc (&info, tdep);
+  tdep->elf_flags = elf_flags;
+  tdep->found_abi = found_abi;
+  tdep->nanomips_abi = nanomips_abi;
+  tdep->fpu_type = fpu_type;
+  tdep->register_size = register_size;
+
+  /* Initially set everything according to the default ABI/ISA.  */
+  set_gdbarch_short_bit (gdbarch, 16);
+  set_gdbarch_int_bit (gdbarch, 32);
+  set_gdbarch_float_bit (gdbarch, 32);
+  set_gdbarch_double_bit (gdbarch, 64);
+  set_gdbarch_long_double_bit (gdbarch, 64);
+  set_gdbarch_register_reggroup_p (gdbarch, nanomips_register_reggroup_p);
+  set_gdbarch_pseudo_register_read (gdbarch, nanomips_pseudo_register_read);
+  set_gdbarch_pseudo_register_write (gdbarch, nanomips_pseudo_register_write);
+  set_gdbarch_ax_pseudo_register_collect (gdbarch,
+					  nanomips_ax_pseudo_register_collect);
+  set_gdbarch_ax_pseudo_register_push_stack
+      (gdbarch, nanomips_ax_pseudo_register_push_stack);
+
+  tdep->default_mask_address_p = 0;
+
+  set_gdbarch_push_dummy_call (gdbarch, nanomips_push_dummy_call);
+  set_gdbarch_return_value (gdbarch, nanomips_return_value);
+
+  switch (nanomips_abi)
+    {
+    case NANOMIPS_ABI_P32:
+      set_gdbarch_long_bit (gdbarch, 32);
+      set_gdbarch_ptr_bit (gdbarch, 32);
+      set_gdbarch_long_long_bit (gdbarch, 64);
+      break;
+    case NANOMIPS_ABI_P64:
+      set_gdbarch_long_bit (gdbarch, 64);
+      set_gdbarch_ptr_bit (gdbarch, 64);
+      set_gdbarch_long_long_bit (gdbarch, 64);
+      set_gdbarch_long_double_bit (gdbarch, 128);
+      set_gdbarch_long_double_format (gdbarch, floatformats_ibm_long_double);
+      break;
+    default:
+      internal_error_loc (__FILE__, __LINE__, _("unknown ABI in switch"));
+    }
+
+  set_gdbarch_read_pc (gdbarch, nanomips_read_pc);
+  set_gdbarch_write_pc (gdbarch, nanomips_write_pc);
+
+  /* Add/remove bits from an address.  The nanoMIPS needs be careful to
+     ensure that all 32 bit addresses are sign extended to 64 bits.  */
+  set_gdbarch_addr_bits_remove (gdbarch, nanomips_addr_bits_remove);
+
+  /* Unwind the frame.  */
+  set_gdbarch_unwind_pc (gdbarch, nanomips_unwind_pc);
+  set_gdbarch_unwind_sp (gdbarch, nanomips_unwind_sp);
+  set_gdbarch_dummy_id (gdbarch, nanomips_dummy_id);
+
+  /* Map debug register numbers onto internal register numbers.  */
+  set_gdbarch_stab_reg_to_regnum (gdbarch, nanomips_stab_reg_to_regnum);
+  set_gdbarch_ecoff_reg_to_regnum (gdbarch,
+				   nanomips_dwarf_dwarf2_ecoff_reg_to_regnum);
+  set_gdbarch_dwarf2_reg_to_regnum (gdbarch,
+				    nanomips_dwarf_dwarf2_ecoff_reg_to_regnum);
+  set_gdbarch_register_sim_regno (gdbarch, nanomips_register_sim_regno);
+
+  /* nanoMIPS version of CALL_DUMMY.  */
+
+  set_gdbarch_call_dummy_location (gdbarch, ON_STACK);
+  set_gdbarch_push_dummy_code (gdbarch, nanomips_push_dummy_code);
+  set_gdbarch_frame_align (gdbarch, nanomips_frame_align);
+
+  set_gdbarch_print_float_info (gdbarch, nanomips_print_float_info);
+
+  set_gdbarch_convert_register_p (gdbarch, nanomips_convert_register_p);
+  set_gdbarch_register_to_value (gdbarch, nanomips_register_to_value);
+  set_gdbarch_value_to_register (gdbarch, nanomips_value_to_register);
+
+  set_gdbarch_inner_than (gdbarch, core_addr_lessthan);
+  set_gdbarch_breakpoint_kind_from_pc (gdbarch,
+				       nanomips_breakpoint_kind_from_pc);
+  set_gdbarch_sw_breakpoint_from_kind (gdbarch,
+				       nanomips_sw_breakpoint_from_kind);
+
+  set_gdbarch_skip_prologue (gdbarch, nanomips_skip_prologue);
+
+  set_gdbarch_stack_frame_destroyed_p (gdbarch,
+				       nanomips_stack_frame_destroyed_p);
+
+  set_gdbarch_pointer_to_address (gdbarch, signed_pointer_to_address);
+  set_gdbarch_address_to_pointer (gdbarch, address_to_signed_pointer);
+  set_gdbarch_integer_to_address (gdbarch, nanomips_integer_to_address);
+
+  set_gdbarch_print_registers_info (gdbarch, nanomips_print_registers_info);
+
+  if (nanomips_abi == NANOMIPS_ABI_P64)
+    set_gdbarch_print_insn (gdbarch, gdb_print_insn_nanomips_p64);
+  else
+    set_gdbarch_print_insn (gdbarch, gdb_print_insn_nanomips_p32);
+
+  /* FIXME: cagney/2003-08-29: The macros target_have_steppable_watchpoint,
+     HAVE_NONSTEPPABLE_WATCHPOINT, and target_have_continuable_watchpoint
+     need to all be folded into the target vector.  Since they are
+     being used as guards for target_stopped_by_watchpoint, why not have
+     target_stopped_by_watchpoint return the type of watchpoint that the code
+     is sitting on?  */
+  set_gdbarch_have_nonsteppable_watchpoint (gdbarch, 1);
+
+  /* Virtual tables.  */
+  set_gdbarch_vbit_in_delta (gdbarch, 0);
+
+  /* Hook in OS ABI-specific overrides, if they have been registered.  */
+  info.target_desc = tdesc;
+  info.tdesc_data = tdesc_data.get ();
+  gdbarch_init_osabi (info, gdbarch);
+
+  /* Unwind the frame.  */
+  dwarf2_append_unwinders (gdbarch);
+  frame_unwind_append_unwinder (gdbarch, &nanomips_frame_unwind);
+  frame_base_append_sniffer (gdbarch, dwarf2_frame_base_sniffer);
+  frame_base_append_sniffer (gdbarch, nanomips_frame_base_sniffer);
+
+  regnum = GDBARCH_OBSTACK_ZALLOC (gdbarch, struct nanomips_regnum);
+  *regnum = nanomips_regnum;
+  tdep->regnum = regnum;
+
+  set_gdbarch_num_regs (gdbarch, num_regs);
+  set_tdesc_pseudo_register_type (gdbarch, nanomips_pseudo_register_type);
+  tdesc_use_registers (gdbarch, info.target_desc, std::move (tdesc_data));
+
+  /* Override the normal target description methods to handle our
+     dual real and pseudo registers.  */
+  set_gdbarch_register_name (gdbarch, nanomips_register_name);
+  set_gdbarch_register_reggroup_p (gdbarch,
+				   nanomips_tdesc_register_reggroup_p);
+
+  /* The target description may have adjusted num_regs, fetch the final
+     value and set pc_regnum and sp_regnum now that it has been fixed.  */
+  num_regs = gdbarch_num_regs (gdbarch);
+  set_gdbarch_num_pseudo_regs (gdbarch, num_regs);
+  set_gdbarch_pc_regnum (gdbarch, NANOMIPS_PC_REGNUM + num_regs);
+  set_gdbarch_sp_regnum (gdbarch, NANOMIPS_SP_REGNUM + num_regs);
+  if (regnum->fpr != -1)
+    set_gdbarch_fp0_regnum (gdbarch, regnum->fpr + NANOMIPS_FP0_REGNUM);
+  set_gdbarch_virtual_frame_pointer (gdbarch, nanomips_virtual_frame_pointer);
+
+  return gdbarch;
+}
+
+static void
+nanomips_dump_tdep (struct gdbarch *gdbarch, struct ui_file *file)
+{
+  struct nanomips_gdbarch_tdep *tdep = gdbarch_tdep<nanomips_gdbarch_tdep> (gdbarch);
+  if (tdep != NULL)
+    {
+      int ef_mips_arch;
+      int ef_mips_32bitmode;
+      /* Determine the ISA.  */
+      switch (tdep->elf_flags & EF_NANOMIPS_ARCH)
+	{
+	case E_NANOMIPS_ARCH_32R6:
+	  ef_mips_arch = 1;
+	  break;
+	case E_NANOMIPS_ARCH_64R6:
+	  ef_mips_arch = 2;
+	  break;
+	default:
+	  ef_mips_arch = 0;
+	  break;
+	}
+      /* Determine the size of a pointer.  */
+      ef_mips_32bitmode = (tdep->elf_flags & EF_NANOMIPS_32BITMODE);
+      gdb_printf (file,
+			  "nanomips_dump_tdep: tdep->elf_flags = 0x%x\n",
+			  tdep->elf_flags);
+      gdb_printf (file,
+			  "nanomips_dump_tdep: ef_mips_32bitmode = %d\n",
+			  ef_mips_32bitmode);
+      gdb_printf (file,
+			  "nanomips_dump_tdep: ef_mips_arch = %d\n",
+			  ef_mips_arch);
+      gdb_printf (file,
+			  "nanomips_dump_tdep: tdep->nanomips_abi = %d (%s)\n",
+			  tdep->nanomips_abi,
+			  nanomips_abi_strings[tdep->nanomips_abi]);
+      gdb_printf (file,
+			  "nanomips_dump_tdep: "
+			  "nanomips_mask_address_p() %d (default %d)\n",
+			  nanomips_mask_address_p (tdep),
+			  tdep->default_mask_address_p);
+    }
+
+  gdb_printf (file,
+		      "nanomips_dump_tdep: FPU_TYPE = %d (%s)\n",
+		      FPU_TYPE (gdbarch),
+		      (FPU_TYPE (gdbarch) == NANOMIPS_FPU_NONE ? "unknown"
+		       : FPU_TYPE (gdbarch) == NANOMIPS_FPU_HARD ?
+						"64bit hardware floating point"
+		       : FPU_TYPE (gdbarch) == NANOMIPS_FPU_SOFT ?
+						"Software floating point"
+		       : "???"));
+}
+
+void _initialize_nanomips_tdep(); /* -Wmissing-prototypes */
+
+void
+_initialize_nanomips_tdep ()
+{
+  gdbarch_register (bfd_arch_nanomips, nanomips_gdbarch_init,
+		    nanomips_dump_tdep);
+
+  initialize_tdesc_nanomips ();
+
+  /* Add root prefix command for all "set/show nanomips" commands.  */
+  add_prefix_cmd ("nanomips", no_class, set_nanomips_command,
+		  _("Various nanoMIPS specific commands."),
+		  &setnanomipscmdlist, 0, &setlist);
+
+  add_prefix_cmd ("nanomips", no_class, show_nanomips_command,
+		  _("Various nanoMIPS specific commands."),
+		  &shownanomipscmdlist, 0, &showlist);
+
+  /* We really would like to have both "0" and "unlimited" work, but
+     command.c doesn't deal with that.  So make it a var_zinteger
+     because the user can always use "999999" or some such for unlimited.  */
+  add_setshow_zinteger_cmd ("heuristic-fence-post", class_support,
+			    &heuristic_fence_post, _("\
+Set the distance searched for the start of a function."), _("\
+Show the distance searched for the start of a function."), _("\
+If you are debugging a stripped executable, GDB needs to search through the\n\
+program for the start of a function.  This command sets the distance of the\n\
+search.  The only need to set it is when debugging a stripped executable."),
+			    reinit_frame_cache_sfunc,
+			    NULL, /* FIXME: i18n: The distance searched for
+				     the start of a function is %s.  */
+			    &setlist, &showlist);
+
+  /* Allow the user to control whether the upper bits of 64-bit
+     addresses should be zeroed.  */
+  add_setshow_auto_boolean_cmd ("mask-address", no_class,
+				&mask_address_var, _("\
+Set zeroing of upper 32 bits of 64-bit addresses."), _("\
+Show zeroing of upper 32 bits of 64-bit addresses."), _("\
+Use \"on\" to enable the masking, \"off\" to disable it and \"auto\" to\n\
+allow GDB to determine the correct value."),
+				NULL, show_mask_address,
+				&setnanomipscmdlist, &shownanomipscmdlist);
+
+  /* Debug this files internals.  */
+  add_setshow_zuinteger_cmd ("nanomips", class_maintenance,
+			     &nanomips_debug, _("\
+Set nanomips debugging."), _("\
+Show nanomips debugging."), _("\
+When non-zero, nanomips specific debugging is enabled."),
+			     NULL,
+			     NULL, /* FIXME: i18n: Mips debugging is
+				      currently %s.  */
+			     &setdebuglist, &showdebuglist);
+}
diff --git a/gdb/nanomips-tdep.h b/gdb/nanomips-tdep.h
new file mode 100644
index 00000000000..97d85ec89d6
--- /dev/null
+++ b/gdb/nanomips-tdep.h
@@ -0,0 +1,144 @@ 
+/* Target-dependent header for the nanoMIPS architecture, for GDB,
+   the GNU Debugger.
+
+   Copyright (C) 2002-2022 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#ifndef NANOMIPS_TDEP_H
+#define NANOMIPS_TDEP_H
+
+#include "objfiles.h"
+
+struct gdbarch;
+
+/* All the possible nanoMIPS ABIs.  */
+enum nanomips_abi
+  {
+    NANOMIPS_ABI_UNKNOWN = 0,
+    NANOMIPS_ABI_P32,
+    NANOMIPS_ABI_P64,
+  };
+
+/* Return the nanoMIPS ABI associated with GDBARCH.  */
+enum nanomips_abi nanomips_abi (struct gdbarch *gdbarch);
+
+/* Return the current index for various nanoMIPS registers.  */
+struct nanomips_regnum
+{
+  int fpr;		/* Floating-point unit registers.  */
+  int badvaddr;		/* Bad vaddr for addressing exception.  */
+  int status;		/* Status register.  */
+  int cause;		/* Describes last exception.  */
+  int dsp;		/* DSP registers.  */
+  int restart;		/* Linux syscall restart flag.  */
+};
+
+extern const struct nanomips_regnum *nanomips_regnum (struct gdbarch *gdbarch);
+
+/* nanoMIPS floating-point operations.  */
+
+enum fpu_type
+{
+  NANOMIPS_FPU_NONE,	/* Unknown floating point.  */
+  NANOMIPS_FPU_HARD,	/* Double precision floating point.  */
+  NANOMIPS_FPU_SOFT	/* Software floating point.  */
+};
+
+/* nanoMIPS specific per-architecture information.  */
+struct nanomips_gdbarch_tdep : gdbarch_tdep_base
+{
+  /* from the elf header */
+  int elf_flags;
+
+  /* nanomips options */
+  enum nanomips_abi nanomips_abi;
+  enum nanomips_abi found_abi;
+  enum fpu_type fpu_type;
+  int mips_last_arg_regnum;
+  int default_mask_address_p;
+
+  /* Indexes for various registers determined dynamically at run time.
+     This contains the "public" fields.  Don't add any that do not need
+     to be public.  */
+  struct nanomips_regnum *regnum;
+
+  /* The size of register data available from the target.  */
+  int register_size;
+
+  /* Return the expected next PC if FRAME is stopped at a syscall
+     instruction.  */
+  CORE_ADDR (*syscall_next_pc) (frame_info_ptr frame, CORE_ADDR pc);
+};
+
+/* Register numbers of various important registers from the fixed
+   GPR+PC register set that is always present.  The rest is determined
+   dynamically at run time and held in `gdbarch_tdep->regnum'.  */
+
+enum
+{
+  NANOMIPS_ZERO_REGNUM = 0,
+  NANOMIPS_AT_REGNUM = 1,
+  NANOMIPS_T4_REGNUM = 2,
+  NANOMIPS_A0_REGNUM = 4,
+  NANOMIPS_GP_REGNUM = 28,
+  NANOMIPS_SP_REGNUM = 29,
+  NANOMIPS_FP_REGNUM = 30,
+  NANOMIPS_RA_REGNUM = 31,
+  NANOMIPS_PC_REGNUM = 32
+};
+
+/* Floating-point register offsets relative to `gdbarch_tdep->regnum->fpr'.  */
+
+enum
+{
+  NANOMIPS_FP0_REGNUM = 0,
+  NANOMIPS_FCSR_REGNUM = 32,
+  NANOMIPS_FIR_REGNUM = 33
+};
+
+/* DSP register offsets, relative to `gdbarch_tdep->regnum->dsp'.  */
+
+enum
+{
+  NANOMIPS_DSPHI0_REGNUM = 0,
+  NANOMIPS_DSPLO0_REGNUM = 1,
+  NANOMIPS_DSPCTL_REGNUM = 8
+};
+
+/* Instruction sizes and other useful constants.  */
+enum
+{
+  INSN16_SIZE = 2,
+  INSN32_SIZE = 4,
+  /* The number of floating-point or integer registers.  */
+  NUMREGS = 32
+};
+
+/* Single step based on where the current instruction will take us.  */
+extern std::vector<CORE_ADDR>
+nanomips_software_single_step (struct regcache *regcache);
+
+/* Return the currently determined ISA register size.  */
+extern int nanomips_isa_regsize (struct gdbarch *gdbarch);
+
+/* Return the currently configured (or set) saved register size.  */
+extern unsigned int nanomips_abi_regsize (struct gdbarch *gdbarch);
+
+/* Make PC the address of the next instruction to execute.  */
+extern void nanomips_write_pc (struct regcache *regcache, CORE_ADDR pc);
+
+#endif /* NANOMIPS_TDEP_H */
diff --git a/gdb/testsuite/gdb.asm/asm-source.exp b/gdb/testsuite/gdb.asm/asm-source.exp
index d56a5076b44..c2ec299a81f 100644
--- a/gdb/testsuite/gdb.asm/asm-source.exp
+++ b/gdb/testsuite/gdb.asm/asm-source.exp
@@ -100,6 +100,13 @@  switch -glob -- [istarget] {
     "mips*-*" {
         set asm-arch mips
     }
+    "nanomips*-elf" {
+        set asm-arch nanomips
+	append link-flags " -Ttext 0x80020000 -Tdata 0x80030000"
+	set board [target_info name]
+	set old_ldscript [board_info $board ldscript]
+	set_board_info ldscript ""
+    }
     "powerpc64le-*" {
         set asm-arch powerpc64le
         set asm-flags "-a64 -I${srcdir}/${subdir} $obj_include"
@@ -260,7 +267,7 @@  if {[target_link [list $asm1obj $asm2obj] "${binfile}" ${link-flags}] != "" } th
 }
 
 # Restore the target board linker script for HC11/HC12.
-if { [istarget "m6811-*-*"] || [istarget "m6812-*-*"] } {
+if { [istarget "m6811-*-*"] || [istarget "m6812-*-*"] || [istarget "nanomips*-elf"] } {
     set_board_info ldscript $old_ldscript
 }
 
diff --git a/gdb/testsuite/gdb.asm/nanomips.inc b/gdb/testsuite/gdb.asm/nanomips.inc
new file mode 100644
index 00000000000..6e2ead15d2c
--- /dev/null
+++ b/gdb/testsuite/gdb.asm/nanomips.inc
@@ -0,0 +1,49 @@ 
+	comment "subroutine declare"
+	.purgem gdbasm_declare
+	.macro gdbasm_declare name
+	.align	1
+	.ent	\name
+	.type	\name,@function
+\name:
+	.endm
+
+	comment "subroutine prologue"
+	.macro gdbasm_enter
+	save 32, $fp, $ra
+	addiu $fp, $sp, -4080
+	.endm
+
+	comment "subroutine epilogue"
+	.macro gdbasm_leave
+	restore.jrc 32, $fp, $ra
+	.endm
+
+	comment "subroutine end"
+	.purgem gdbasm_end
+	.macro gdbasm_end name
+	.end	\name
+	.endm
+
+	.macro gdbasm_call subr
+        li     $t9, \subr
+        jalrc  $ra, $t9
+	.endm
+
+	.macro gdbasm_several_nops
+	nop
+	nop
+	nop
+	nop
+	.endm
+
+	comment "exit (0)"
+	.macro gdbasm_exit0
+	comment "Don't know how to exit, but this will certainly halt..."
+	lw 	$a3, 0($zero)
+	.endm
+
+	comment "crt0 startup"
+	.macro gdbasm_startup
+	li $sp, 0x8007fff0
+	li $fp, 0
+	.endm
diff --git a/gdb/testsuite/gdb.base/catch-gdb-caused-signals.c b/gdb/testsuite/gdb.base/catch-gdb-caused-signals.c
index e9923814b01..a2064b3bb2e 100644
--- a/gdb/testsuite/gdb.base/catch-gdb-caused-signals.c
+++ b/gdb/testsuite/gdb.base/catch-gdb-caused-signals.c
@@ -27,6 +27,9 @@  main (void)
 {
   int i = 0;
 
+  /* Ensure printf function is available.  */
+  printf ("printf available %d\n", i);
+
   gdb_unbuffer_output ();
 
   i++; /* set dprintf here */
diff --git a/gdb/testsuite/gdb.base/float.exp b/gdb/testsuite/gdb.base/float.exp
index 7fff2b90727..76a274e936a 100644
--- a/gdb/testsuite/gdb.base/float.exp
+++ b/gdb/testsuite/gdb.base/float.exp
@@ -67,7 +67,7 @@  if { [is_aarch64_target] } then {
             pass "info float (without FPU)"
 	}
     }
-} elseif [istarget "mips*-*-*"] then {
+} elseif { [istarget "mips*-*-*"] || [istarget "nanomips*-*-*"] } then {
     gdb_test_multiple "info float" "info float" {
 	-re "fpu type: none / unused\r\n$gdb_prompt $" {
 	      pass "info float (without FPU)"
diff --git a/gdb/testsuite/gdb.trace/trace-common.h b/gdb/testsuite/gdb.trace/trace-common.h
index f8cd654ba2b..6dfab081f1e 100644
--- a/gdb/testsuite/gdb.trace/trace-common.h
+++ b/gdb/testsuite/gdb.trace/trace-common.h
@@ -43,7 +43,7 @@  x86_trace_dummy ()
        "    call " SYMBOL(x86_trace_dummy) "\n" \
        )
 
-#elif (defined __aarch64__) || (defined __powerpc__)
+#elif (defined __aarch64__) || (defined __powerpc__) || (__nanomips__)
 
 #define FAST_TRACEPOINT_LABEL(name) \
   asm ("    .global " SYMBOL(name) "\n" \
diff --git a/gdb/testsuite/lib/gdb.exp b/gdb/testsuite/lib/gdb.exp
index 7d05fbe557b..2df0d35ffa0 100644
--- a/gdb/testsuite/lib/gdb.exp
+++ b/gdb/testsuite/lib/gdb.exp
@@ -3284,6 +3284,7 @@  gdb_caching_proc supports_memtag {
 proc can_hardware_single_step {} {
 
     if { [istarget "arm*-*-*"] || [istarget "mips*-*-*"]
+	 || [istarget "nanomips*-*-*"]
 	 || [istarget "tic6x-*-*"] || [istarget "sparc*-*-linux*"]
 	 || [istarget "nios2-*-*"] || [istarget "riscv*-*-linux*"] } {
 	return 0