On Wed, 2024-07-03 at 11:59 +0200, Sébastien Michelland wrote:
> libgcc's fp-bit.c is quite slow and most modern/developed architectures
> have switched to using the soft-fp library. This patch does so for
> free-standing/unknown-OS SH3/SH4 builds, using soft-fp's default parameters
> for the most part, most notably no exceptions.
>
> A quick run of Whetstone (built with OpenLibm) on an SH4 machine shows
> about x3 speedup (~320 -> 1050 Kwhets/s).
>
> I'm sending this as RFC because I'm quite unsure about testing. I built
> the compiler and ran the benchmark, but I don't know if GCC has a test
> for soft-fp correctness and whether I can run that in my non-hosted
> environment. Any advice?
>
As discussed, the patch was changed to use soft-fp not only for SH3/SH4 but
generally for all sh-elf targets.
sh-*-linux* and sh-*-rtems* are not affected by that and continue using the
fdpbit library for floating-point emulation on no-fpu variants. If that
should be changed as well, please let me know.
Tested with
make -k check RUNTESTFLAGS="--target_board=sh-sim\{-m2/-ml,-m2/-mb}"
committed & pushed the attached version to master.
Best regards,
Oleg Endo
From e95512e2d5a317e8c043f232158df4b38186e51c Mon Sep 17 00:00:00 2001
From: Sébastien Michelland <sebastien.michell...@lcis.grenoble-inp.fr>
Date: Thu, 10 Oct 2024 09:24:39 +0900
Subject: [PATCH] SH: Use softfp for sh-elf
libgcc/ChangeLog:
PR target/29845
* config.host (sh-*-elf*): Replace fdpbit with softfp.
* config/sh/sfp-machine.h: New file.
Signed-off-by: Sébastien Michelland <sebastien.michell...@lcis.grenoble-inp.fr>
---
libgcc/config.host | 2 +-
libgcc/config/sh/sfp-machine.h | 83 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 84 insertions(+), 1 deletion(-)
create mode 100644 libgcc/config/sh/sfp-machine.h
diff --git a/libgcc/config.host b/libgcc/config.host
index fa001c5..06fae15 100644
--- a/libgcc/config.host
+++ b/libgcc/config.host
@@ -1413,9 +1413,9 @@ s390x-ibm-tpf*)
extra_parts="crtbeginS.o crtendS.o"
md_unwind_header=s390/tpf-unwind.h
;;
sh-*-elf* | sh[12346l]*-*-elf*)
- tmake_file="$tmake_file sh/t-sh t-crtstuff-pic t-fdpbit"
+ tmake_file="$tmake_file sh/t-sh t-crtstuff-pic t-softfp-sfdf t-softfp"
extra_parts="$extra_parts crt1.o crti.o crtn.o crtbeginS.o crtendS.o \
libic_invalidate_array_4-100.a \
libic_invalidate_array_4-200.a \
libic_invalidate_array_4a.a \
diff --git a/libgcc/config/sh/sfp-machine.h b/libgcc/config/sh/sfp-machine.h
new file mode 100644
index 0000000..26f6516
--- /dev/null
+++ b/libgcc/config/sh/sfp-machine.h
@@ -0,0 +1,83 @@
+/* Software floating-point machine description for SuperH.
+
+Copyright (C) 2024 Free Software Foundation, Inc.
+
+This file is part of GCC.
+
+GCC 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, or (at your option) any later
+version.
+
+GCC 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.
+
+Under Section 7 of GPL version 3, you are granted additional
+permissions described in the GCC Runtime Library Exception, version
+3.1, as published by the Free Software Foundation.
+
+You should have received a copy of the GNU General Public License and
+a copy of the GCC Runtime Library Exception along with this program;
+see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
+<http://www.gnu.org/licenses/>. */
+
+#define _FP_W_TYPE_SIZE 32
+#define _FP_W_TYPE unsigned long
+#define _FP_WS_TYPE signed long
+#define _FP_I_TYPE long
+
+#define _FP_MUL_MEAT_S(R,X,Y) \
+ _FP_MUL_MEAT_1_wide(_FP_WFRACBITS_S,R,X,Y,umul_ppmm)
+#define _FP_MUL_MEAT_D(R,X,Y) \
+ _FP_MUL_MEAT_2_wide(_FP_WFRACBITS_D,R,X,Y,umul_ppmm)
+#define _FP_MUL_MEAT_Q(R,X,Y) \
+ _FP_MUL_MEAT_4_wide(_FP_WFRACBITS_Q,R,X,Y,umul_ppmm)
+
+#define _FP_DIV_MEAT_S(R,X,Y) _FP_DIV_MEAT_1_udiv_norm(S,R,X,Y)
+#define _FP_DIV_MEAT_D(R,X,Y) _FP_DIV_MEAT_2_udiv(D,R,X,Y)
+#define _FP_DIV_MEAT_Q(R,X,Y) _FP_DIV_MEAT_4_udiv(Q,R,X,Y)
+
+#define _FP_NANFRAC_B _FP_QNANBIT_B
+#define _FP_NANFRAC_H _FP_QNANBIT_H
+#define _FP_NANFRAC_S _FP_QNANBIT_S
+#define _FP_NANFRAC_D _FP_QNANBIT_D, 0
+#define _FP_NANFRAC_Q _FP_QNANBIT_Q, 0, 0, 0
+
+/* The type of the result of a floating point comparison. This must
+ match __libgcc_cmp_return__ in GCC for the target. */
+typedef int __gcc_CMPtype __attribute__ ((mode (__libgcc_cmp_return__)));
+#define CMPtype __gcc_CMPtype
+
+#define _FP_NANSIGN_B 0
+#define _FP_NANSIGN_H 0
+#define _FP_NANSIGN_S 0
+#define _FP_NANSIGN_D 0
+#define _FP_NANSIGN_Q 0
+
+#define _FP_KEEPNANFRACP 0
+#define _FP_QNANNEGATEDP 0
+
+#define _FP_CHOOSENAN(fs, wc, R, X, Y, OP) \
+ do { \
+ R##_s = _FP_NANSIGN_##fs; \
+ _FP_FRAC_SET_##wc(R,_FP_NANFRAC_##fs); \
+ R##_c = FP_CLS_NAN; \
+ } while (0)
+
+#define _FP_TININESS_AFTER_ROUNDING 1
+
+#define __LITTLE_ENDIAN 1234
+#define __BIG_ENDIAN 4321
+
+#if defined(__BYTE_ORDER__) && (__BYTE_ORDER__ == __ORDER_BIG_ENDIAN__)
+#define __BYTE_ORDER __BIG_ENDIAN
+#else
+#define __BYTE_ORDER __LITTLE_ENDIAN
+#endif
+
+/* Define ALIASNAME as a strong alias for NAME. */
+# define strong_alias(name, aliasname) _strong_alias(name, aliasname)
+# define _strong_alias(name, aliasname) \
+ extern __typeof (name) aliasname __attribute__ ((alias (#name)));
--
libgit2 1.7.2
