[v6] gdb/hppa-tdep.c: Fix logical working flow issues and check additional store instructions.
Commit Message
Original working flow has several issues:
- typo issue: "(inst >> 26) == 0x1f && ..." for checking 'stw(m)'.
- "(inst >> 6) == 0xa" needs to be "((inst >> 6) & 0xf) == 0xa".
And also need check additional store instructions:
- For absolute memory: 'stby', 'stdby'.
- For unaligned: 'stwa', 'stda'.
The original code also can be improved:
- Remove redundant double check "(inst >> 26) == 0x1b" for 'stwm'.
- Use 2 'switch' statements instead of all 'if' statements.
* hppa-tdep.c (inst_saves_gr): Fix logical working flow issues
and check additional store instructions.
---
gdb/ChangeLog | 5 +++
gdb/hppa-tdep.c | 121 ++++++++++++++++++++++++++++++++++++++++++++------------
2 files changed, 100 insertions(+), 26 deletions(-)
@@ -1,3 +1,8 @@
+2015-01-22 Chen Gang <gang.chen.5i5j@gmail.com>
+
+ * hppa-tdep.c (inst_saves_gr): Fix logical working flow issues
+ and check additional store instructions.
+
2015-01-21 Wei-cheng Wang <cole945@gmail.com>
* MAINTAINERS (Write After Approval): Add "Wei-cheng Wang".
@@ -1376,37 +1376,106 @@ is_branch (unsigned long inst)
}
/* Return the register number for a GR which is saved by INST or
- zero it INST does not save a GR. */
+ zero if INST does not save a GR.
-static int
-inst_saves_gr (unsigned long inst)
-{
- /* Does it look like a stw? */
- if ((inst >> 26) == 0x1a || (inst >> 26) == 0x1b
- || (inst >> 26) == 0x1f
- || ((inst >> 26) == 0x1f
- && ((inst >> 6) == 0xa)))
- return hppa_extract_5R_store (inst);
+ Referenced from:
- /* Does it look like a std? */
- if ((inst >> 26) == 0x1c
- || ((inst >> 26) == 0x03
- && ((inst >> 6) & 0xf) == 0xb))
- return hppa_extract_5R_store (inst);
+ parisc 1.1:
+ https://parisc.wiki.kernel.org/images-parisc/6/68/Pa11_acd.pdf
- /* Does it look like a stwm? GCC & HPC may use this in prologues. */
- if ((inst >> 26) == 0x1b)
- return hppa_extract_5R_store (inst);
+ parisc 2.0:
+ https://parisc.wiki.kernel.org/images-parisc/7/73/Parisc2.0.pdf
- /* Does it look like sth or stb? HPC versions 9.0 and later use these
- too. */
- if ((inst >> 26) == 0x19 || (inst >> 26) == 0x18
- || ((inst >> 26) == 0x3
- && (((inst >> 6) & 0xf) == 0x8
- || ((inst >> 6) & 0xf) == 0x9)))
- return hppa_extract_5R_store (inst);
+ According to Table 6-5 of Chapter 6 (Memory Reference Instructions)
+ on page 106 in parisc 2.0, all instructions for storing values from
+ the general registers are:
- return 0;
+ Store: stb, sth, stw, std (according to Chapter 7, they
+ are only in both "inst >> 26" and "inst >> 6".
+ Store Absolute: stwa, stda (according to Chapter 7, they are only
+ in "inst >> 6".
+ Store Bytes: stby, stdby (according to Chapter 7, they are
+ only in "inst >> 6").
+
+ For (inst >> 26), according to Chapter 7:
+
+ The effective memory reference address is formed by the addition
+ of an immediate displacement to a base value.
+
+ - stb: 0x18, store a byte from a general register.
+
+ - sth: 0x19, store a halfword from a general register.
+
+ - stw: 0x1a, store a word from a general register.
+
+ - stwm: 0x1b, store a word from a general register and perform base
+ register modification (2.0 will still treate it as stw).
+
+ - std: 0x1c, store a doubleword from a general register (2.0 only).
+
+ - stw: 0x1f, store a word from a general register (2.0 only).
+
+ For (inst >> 6) when ((inst >> 26) == 0x03), according to Chapter 7:
+
+ The effective memory reference address is formed by the addition
+ of an index value to a base value specified in the instruction.
+
+ - stb: 0x08, store a byte from a general register (1.1 calls stbs).
+
+ - sth: 0x09, store a halfword from a general register (1.1 calls
+ sths).
+
+ - stw: 0x0a, store a word from a general register (1.1 calls stws).
+
+ - std: 0x0b: store a doubleword from a general register (2.0 only)
+
+ Implement fast byte moves (stores) to unaligned word or doubleword
+ destination.
+
+ - stby: 0x0c, for unaligned word (1.1 calls stbys).
+
+ - stdby: 0x0d for unaligned doubleword (2.0 only).
+
+ Store a word or doubleword using an absolute memory address formed
+ using short or long displacement or indexed
+
+ - stwa: 0x0e, store a word from a general register to an absolute
+ address (1.0 calls stwas).
+
+ - stda: 0x0f, store a doubleword from a general register to an
+ absolute address (2.0 only). */
+
+static int
+inst_saves_gr (unsigned long inst)
+{
+ switch ((inst >> 26) & 0x0f)
+ {
+ case 0x03:
+ switch ((inst >> 6) & 0x0f)
+ {
+ case 0x08:
+ case 0x09:
+ case 0x0a:
+ case 0x0b:
+ case 0x0c:
+ case 0x0d:
+ case 0x0e:
+ case 0x0f:
+ return hppa_extract_5R_store (inst);
+ default:
+ return 0;
+ }
+ case 0x18:
+ case 0x19:
+ case 0x1a:
+ case 0x1b:
+ case 0x1c:
+ /* no 0x1d or 0x1e -- according to parisc 2.0 document */
+ case 0x1f:
+ return hppa_extract_5R_store (inst);
+ default:
+ return 0;
+ }
}
/* Return the register number for a FR which is saved by INST or