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?
Cheers,
Sébastien
libgcc/ChangeLog:
* config.host: Use soft-fp library for non-hosted SH3/SH4
instead of fpdbit.
* config/sh/sfp-machine.h: New.
Signed-off-by: Sébastien Michelland <sebastien.michell...@lcis.grenoble-inp.fr>
---
libgcc/config.host | 10 +++-
libgcc/config/sh/sfp-machine.h | 83 ++++++++++++++++++++++++++++++++++
2 files changed, 92 insertions(+), 1 deletion(-)
create mode 100644 libgcc/config/sh/sfp-machine.h
diff --git a/libgcc/config.host b/libgcc/config.host
index 9fae51d4c..fee3bf0c0 100644
--- a/libgcc/config.host
+++ b/libgcc/config.host
@@ -1399,7 +1399,15 @@ s390x-ibm-tpf*)
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"
+ case ${host} in
+ sh[34]*-*-elf*)
+ tmake_file="${tmake_file} t-softfp-sfdf t-softfp"
+ ;;
+ *)
+ tmake_file="${tmake_file} t-fdpbit"
+ ;;
+ esac
extra_parts="$extra_parts crt1.o crti.o crtn.o crtbeginS.o crtendS.o \
libic_invalidate_array_4-100.a \
libic_invalidate_array_4-200.a \
diff --git a/libgcc/config/sh/sfp-machine.h b/libgcc/config/sh/sfp-machine.h
new file mode 100644
index 000000000..c1aa428c0
--- /dev/null
+++ b/libgcc/config/sh/sfp-machine.h
@@ -0,0 +1,83 @@
+/* Software floating-point machine description for SuperH.
+
+ Copyright (C) 2016-2024 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)));
--
2.45.2
