[2/2] RISC-V: Add implementation for fmaximum_num and fminimum_num
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Commit Message
Implemented `fmaximum_num{f}` and `fminimum_num{f}` using hard-float `fclass.fmt` and `f{max,min}.fmt` instructions to generate more simplified code.
Signed-off-by: Julian Zhu <jz531210@gmail.com>
---
sysdeps/riscv/rvd/s_fmaximum_num.c | 44 +++++++++++++++++++++++++++++
sysdeps/riscv/rvd/s_fminimum_num.c | 44 +++++++++++++++++++++++++++++
sysdeps/riscv/rvf/s_fmaximum_numf.c | 44 +++++++++++++++++++++++++++++
sysdeps/riscv/rvf/s_fminimum_numf.c | 44 +++++++++++++++++++++++++++++
4 files changed, 176 insertions(+)
create mode 100644 sysdeps/riscv/rvd/s_fmaximum_num.c
create mode 100644 sysdeps/riscv/rvd/s_fminimum_num.c
create mode 100644 sysdeps/riscv/rvf/s_fmaximum_numf.c
create mode 100644 sysdeps/riscv/rvf/s_fminimum_numf.c
Comments
On Wed, 11 Sep 2024, Julian Zhu wrote:
> + if (__glibc_unlikely((_FCLASS (x) & _FCLASS_NAN) && !(_FCLASS (y) & _FCLASS_NAN)))
> + {
> + asm volatile ("fmax.d %0, %1, %2" : "=f" (res) : "f" (x), "f" (y));
> + return res;
> + }
> + else if (__glibc_unlikely(!(_FCLASS (x) & _FCLASS_NAN) && (_FCLASS (y) & _FCLASS_NAN)))
> + {
> + asm volatile ("fmax.d %0, %1, %2" : "=f" (res) : "f" (x), "f" (y));
> + return res;
> + }
> + else
> + {
> + asm volatile ("fmax.d %0, %1, %2" : "=f" (res) : "f" (x), "f" (y));
> + return res;
I don't follow the logic here, which seems to do the same thing under each
of three different runtime conditions.
If the processor implements version 2.2 of the F and D extensions, the
fmax and fmin instructions implement IEEE 754-2019 maximumNumber /
minimumNumber, which is appropriate for fmaximum_num / fminimum_num
(without special runtime conditions about NaNs being needed).
If the processor implements an older version of the F and D extensions,
the fmax and fmin instructions implement IEEE 754-2008 maxNum / minNum,
which is appropriate for fmax / fmin.
If you don't know what version the processor implements, maybe you can do
something with runtime conditions for NaNs, but I don't think they'd look
like the above conditions, because checking runtime conditions is useless
when you end up executing the same asm under all conditions.
new file mode 100644
@@ -0,0 +1,44 @@
+/* Return maximum number of X and Y. RISC-V version.
+ Copyright (C) 2024 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library 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
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <https://www.gnu.org/licenses/>. */
+
+#include <math.h>
+#include <fenv_private.h>
+#include <libm-alias-double.h>
+
+double
+__fmaximum_num (double x, double y)
+{
+ double res;
+
+ if (__glibc_unlikely((_FCLASS (x) & _FCLASS_NAN) && !(_FCLASS (y) & _FCLASS_NAN)))
+ {
+ asm volatile ("fmax.d %0, %1, %2" : "=f" (res) : "f" (x), "f" (y));
+ return res;
+ }
+ else if (__glibc_unlikely(!(_FCLASS (x) & _FCLASS_NAN) && (_FCLASS (y) & _FCLASS_NAN)))
+ {
+ asm volatile ("fmax.d %0, %1, %2" : "=f" (res) : "f" (x), "f" (y));
+ return res;
+ }
+ else
+ {
+ asm volatile ("fmax.d %0, %1, %2" : "=f" (res) : "f" (x), "f" (y));
+ return res;
+ }
+}
+libm_alias_double (__fmaximum_num, fmaximum_num)
new file mode 100644
@@ -0,0 +1,44 @@
+/* Return minimum number of X and Y. RISC-V version.
+ Copyright (C) 2024 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library 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
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <https://www.gnu.org/licenses/>. */
+
+#include <math.h>
+#include <fenv_private.h>
+#include <libm-alias-double.h>
+
+double
+__fminimum_num (double x, double y)
+{
+ double res;
+
+ if (__glibc_unlikely((_FCLASS (x) & _FCLASS_NAN) && !(_FCLASS (y) & _FCLASS_NAN)))
+ {
+ asm volatile ("fmin.d %0, %1, %2" : "=f" (res) : "f" (x), "f" (y));
+ return res;
+ }
+ else if (__glibc_unlikely(!(_FCLASS (x) & _FCLASS_NAN) && (_FCLASS (y) & _FCLASS_NAN)))
+ {
+ asm volatile ("fmin.d %0, %1, %2" : "=f" (res) : "f" (x), "f" (y));
+ return res;
+ }
+ else
+ {
+ asm volatile ("fmin.d %0, %1, %2" : "=f" (res) : "f" (x), "f" (y));
+ return res;
+ }
+}
+libm_alias_double (__fminimum_num, fminimum_num)
new file mode 100644
@@ -0,0 +1,44 @@
+/* Return maximum number of X and Y. RISC-V version.
+ Copyright (C) 2024 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library 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
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <https://www.gnu.org/licenses/>. */
+
+#include <math.h>
+#include <fenv_private.h>
+#include <libm-alias-float.h>
+
+float
+__fmaximum_numf (float x, float y)
+{
+ float res;
+
+ if (__glibc_unlikely((_FCLASS (x) & _FCLASS_NAN) && !(_FCLASS (y) & _FCLASS_NAN)))
+ {
+ asm volatile ("fmax.s %0, %1, %2" : "=f" (res) : "f" (x), "f" (y));
+ return res;
+ }
+ else if (__glibc_unlikely(!(_FCLASS (x) & _FCLASS_NAN) && (_FCLASS (y) & _FCLASS_NAN)))
+ {
+ asm volatile ("fmax.s %0, %1, %2" : "=f" (res) : "f" (x), "f" (y));
+ return res;
+ }
+ else
+ {
+ asm volatile ("fmax.s %0, %1, %2" : "=f" (res) : "f" (x), "f" (y));
+ return res;
+ }
+}
+libm_alias_float (__fmaximum_num, fmaximum_num)
new file mode 100644
@@ -0,0 +1,44 @@
+/* Return minimum number of X and Y. RISC-V version.
+ Copyright (C) 2024 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library 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
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <https://www.gnu.org/licenses/>. */
+
+#include <math.h>
+#include <fenv_private.h>
+#include <libm-alias-float.h>
+
+float
+__fminimum_numf (float x, float y)
+{
+ float res;
+
+ if (__glibc_unlikely((_FCLASS (x) & _FCLASS_NAN) && !(_FCLASS (y) & _FCLASS_NAN)))
+ {
+ asm volatile ("fmin.s %0, %1, %2" : "=f" (res) : "f" (x), "f" (y));
+ return res;
+ }
+ else if (__glibc_unlikely(!(_FCLASS (x) & _FCLASS_NAN) && (_FCLASS (y) & _FCLASS_NAN)))
+ {
+ asm volatile ("fmin.s %0, %1, %2" : "=f" (res) : "f" (x), "f" (y));
+ return res;
+ }
+ else
+ {
+ asm volatile ("fmin.s %0, %1, %2" : "=f" (res) : "f" (x), "f" (y));
+ return res;
+ }
+}
+libm_alias_float (__fminimum_num, fminimum_num)