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Re: [PATCH] x86-64: Add wmemset optimized with SSE2/AVX2/AVX512
- From: "Rodriguez Bahena, Victor" <victor dot rodriguez dot bahena at intel dot com>
- To: "H.J. Lu" <hjl dot tools at gmail dot com>, GNU C Library <libc-alpha at sourceware dot org>
- Date: Wed, 31 May 2017 11:29:24 +0000
- Subject: Re: [PATCH] x86-64: Add wmemset optimized with SSE2/AVX2/AVX512
- Authentication-results: sourceware.org; auth=none
- References: <20170521203442.GA20131@gmail.com> <CAMe9rOrTUvjYcCYnSKS-7Y8A63-MjFOwQHMATSkLoE8ZCt=thw@mail.gmail.com>
+1
-----Original Message-----
From: <libc-alpha-owner@sourceware.org> on behalf of "H.J. Lu"
<hjl.tools@gmail.com>
Date: Tuesday, May 30, 2017 at 6:41 PM
To: GNU C Library <libc-alpha@sourceware.org>
Subject: Re: [PATCH] x86-64: Add wmemset optimized with SSE2/AVX2/AVX512
>On Sun, May 21, 2017 at 1:34 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
>> The difference between memset and wmemset is byte vs int. Add stubs
>> to SSE2/AVX2/AVX512 memset for wmemset with updated constant and size:
>>
>> SSE2 wmemset:
>> shl $0x2,%rdx
>> movd %esi,%xmm0
>> mov %rdi,%rax
>> pshufd $0x0,%xmm0,%xmm0
>> jmp entry_from_wmemset
>>
>> SSE2 memset:
>> movd %esi,%xmm0
>> mov %rdi,%rax
>> punpcklbw %xmm0,%xmm0
>> punpcklwd %xmm0,%xmm0
>> pshufd $0x0,%xmm0,%xmm0
>> entry_from_wmemset:
>>
>> Since the ERMS versions of wmemset requires "rep stosl" instead of
>> "rep stosb", only the vector store stubs of SSE2/AVX2/AVX512 wmemset
>> are added. The SSE2 wmemset is about 3X faster and the AVX2 wmemset
>> is about 6X faster on Haswell.
>>
>> OK for master?
>
>Any objections?
>
>> H.J.
>> ---
>> * include/wchar.h (__wmemset_chk): New.
>> * sysdeps/x86_64/memset.S (VDUP_TO_VEC0_AND_SET_RETURN): Renamed
>> to MEMSET_VDUP_TO_VEC0_AND_SET_RETURN.
>> (WMEMSET_VDUP_TO_VEC0_AND_SET_RETURN): New.
>> (WMEMSET_CHK_SYMBOL): Likewise.
>> (WMEMSET_SYMBOL): Likewise.
>> (__wmemset): Add hidden definition.
>> (wmemset): Add weak hidden definition.
>> * sysdeps/x86_64/multiarch/ifunc-impl-list.c
>> (__libc_ifunc_impl_list): Add __wmemset_sse2_unaligned,
>> __wmemset_avx2_unaligned, __wmemset_avx512_unaligned,
>> __wmemset_chk_sse2_unaligned, __wmemset_chk_avx2_unaligned
>> and __wmemset_chk_avx512_unaligned.
>> * sysdeps/x86_64/multiarch/memset-avx2-unaligned-erms.S
>> (VDUP_TO_VEC0_AND_SET_RETURN): Renamed to ...
>> (MEMSET_VDUP_TO_VEC0_AND_SET_RETURN): This.
>> (WMEMSET_VDUP_TO_VEC0_AND_SET_RETURN): New.
>> (WMEMSET_SYMBOL): Likewise.
>> * sysdeps/x86_64/multiarch/memset-avx512-unaligned-erms.S
>> (VDUP_TO_VEC0_AND_SET_RETURN): Renamed to ...
>> (MEMSET_VDUP_TO_VEC0_AND_SET_RETURN): This.
>> (WMEMSET_VDUP_TO_VEC0_AND_SET_RETURN): New.
>> (WMEMSET_SYMBOL): Likewise.
>> * sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S: Updated.
>> (WMEMSET_CHK_SYMBOL): New.
>> (WMEMSET_CHK_SYMBOL (__wmemset_chk, unaligned)): Likewise.
>> (WMEMSET_SYMBOL (__wmemset, unaligned)): Likewise.
>> * sysdeps/x86_64/multiarch/memset.S (WMEMSET_SYMBOL): New.
>> (libc_hidden_builtin_def): Also define __GI_wmemset and
>> __GI___wmemset.
>> (weak_alias): New.
>> * sysdeps/x86_64/multiarch/wmemset.S: New file.
>> * sysdeps/x86_64/multiarch/wmemset_chk.S: Likewise.
>> * sysdeps/x86_64/wmemset.S: Likewise.
>> * sysdeps/x86_64/wmemset_chk.S: Likewise.
>> ---
>> include/wchar.h | 3 ++
>> sysdeps/x86_64/memset.S | 18 ++++++++-
>> sysdeps/x86_64/multiarch/ifunc-impl-list.c | 22 ++++++++++
>> .../x86_64/multiarch/memset-avx2-unaligned-erms.S | 8 +++-
>> .../multiarch/memset-avx512-unaligned-erms.S | 9 ++++-
>> .../x86_64/multiarch/memset-vec-unaligned-erms.S | 24 +++++++++--
>> sysdeps/x86_64/multiarch/memset.S | 13 ++++--
>> sysdeps/x86_64/multiarch/wmemset.S | 47
>>++++++++++++++++++++++
>> sysdeps/x86_64/multiarch/wmemset_chk.S | 46
>>+++++++++++++++++++++
>> sysdeps/x86_64/wmemset.S | 1 +
>> sysdeps/x86_64/wmemset_chk.S | 33 +++++++++++++++
>> 11 files changed, 215 insertions(+), 9 deletions(-)
>> create mode 100644 sysdeps/x86_64/multiarch/wmemset.S
>> create mode 100644 sysdeps/x86_64/multiarch/wmemset_chk.S
>> create mode 100644 sysdeps/x86_64/wmemset.S
>> create mode 100644 sysdeps/x86_64/wmemset_chk.S
>>
>> diff --git a/include/wchar.h b/include/wchar.h
>> index e2579a1..a773d56 100644
>> --- a/include/wchar.h
>> +++ b/include/wchar.h
>> @@ -157,6 +157,9 @@ extern wchar_t *__wmemmove (wchar_t *__s1, const
>>wchar_t *__s2,
>> extern wchar_t *__wcschrnul (const wchar_t *__s, wchar_t __wc)
>> __attribute_pure__;
>>
>> +extern wchar_t *__wmemset_chk (wchar_t *__s, wchar_t __c, size_t __n,
>> + size_t __ns) __THROW;
>> +
>> extern int __vfwscanf (__FILE *__restrict __s,
>> const wchar_t *__restrict __format,
>> __gnuc_va_list __arg)
>> diff --git a/sysdeps/x86_64/memset.S b/sysdeps/x86_64/memset.S
>> index 69ed509..4127878 100644
>> --- a/sysdeps/x86_64/memset.S
>> +++ b/sysdeps/x86_64/memset.S
>> @@ -26,13 +26,18 @@
>> #define VMOVU movdqu
>> #define VMOVA movdqa
>>
>> -#define VDUP_TO_VEC0_AND_SET_RETURN(d, r) \
>> +#define MEMSET_VDUP_TO_VEC0_AND_SET_RETURN(d, r) \
>> movd d, %xmm0; \
>> movq r, %rax; \
>> punpcklbw %xmm0, %xmm0; \
>> punpcklwd %xmm0, %xmm0; \
>> pshufd $0, %xmm0, %xmm0
>>
>> +#define WMEMSET_VDUP_TO_VEC0_AND_SET_RETURN(d, r) \
>> + movd d, %xmm0; \
>> + movq r, %rax; \
>> + pshufd $0, %xmm0, %xmm0
>> +
>> #define SECTION(p) p
>>
>> #ifndef MEMSET_SYMBOL
>> @@ -40,10 +45,21 @@
>> # define MEMSET_SYMBOL(p,s) memset
>> #endif
>>
>> +#ifndef WMEMSET_SYMBOL
>> +# define WMEMSET_CHK_SYMBOL(p,s) p
>> +# define WMEMSET_SYMBOL(p,s) __wmemset
>> +#endif
>> +
>> #include "multiarch/memset-vec-unaligned-erms.S"
>>
>> libc_hidden_builtin_def (memset)
>>
>> +#if IS_IN (libc)
>> +libc_hidden_def (__wmemset)
>> +weak_alias (__wmemset, wmemset)
>> +libc_hidden_weak (wmemset)
>> +#endif
>> +
>> #if defined SHARED && IS_IN (libc) && !defined USE_MULTIARCH
>> strong_alias (__memset_chk, __memset_zero_constant_len_parameter)
>> .section .gnu.warning.__memset_zero_constant_len_parameter
>> diff --git a/sysdeps/x86_64/multiarch/ifunc-impl-list.c
>>b/sysdeps/x86_64/multiarch/ifunc-impl-list.c
>> index 06d9a9d..a91d2f9 100644
>> --- a/sysdeps/x86_64/multiarch/ifunc-impl-list.c
>> +++ b/sysdeps/x86_64/multiarch/ifunc-impl-list.c
>> @@ -300,6 +300,17 @@ __libc_ifunc_impl_list (const char *name, struct
>>libc_ifunc_impl *array,
>> __wmemcmp_ssse3)
>> IFUNC_IMPL_ADD (array, i, wmemcmp, 1, __wmemcmp_sse2))
>>
>> + /* Support sysdeps/x86_64/multiarch/wmemset.S. */
>> + IFUNC_IMPL (i, name, wmemset,
>> + IFUNC_IMPL_ADD (array, i, wmemset, 1,
>> + __wmemset_sse2_unaligned)
>> + IFUNC_IMPL_ADD (array, i, wmemset,
>> + HAS_ARCH_FEATURE (AVX2_Usable),
>> + __wmemset_avx2_unaligned)
>> + IFUNC_IMPL_ADD (array, i, wmemset,
>> + HAS_ARCH_FEATURE (AVX512F_Usable),
>> + __wmemset_avx512_unaligned))
>> +
>> #ifdef SHARED
>> /* Support sysdeps/x86_64/multiarch/memcpy_chk.S. */
>> IFUNC_IMPL (i, name, __memcpy_chk,
>> @@ -417,6 +428,17 @@ __libc_ifunc_impl_list (const char *name, struct
>>libc_ifunc_impl *array,
>> IFUNC_IMPL_ADD (array, i, strncmp, HAS_CPU_FEATURE
>>(SSSE3),
>> __strncmp_ssse3)
>> IFUNC_IMPL_ADD (array, i, strncmp, 1, __strncmp_sse2))
>> +
>> + /* Support sysdeps/x86_64/multiarch/wmemset_chk.S. */
>> + IFUNC_IMPL (i, name, __wmemset_chk,
>> + IFUNC_IMPL_ADD (array, i, __wmemset_chk, 1,
>> + __wmemset_chk_sse2_unaligned)
>> + IFUNC_IMPL_ADD (array, i, __wmemset_chk,
>> + HAS_ARCH_FEATURE (AVX2_Usable),
>> + __wmemset_chk_avx2_unaligned)
>> + IFUNC_IMPL_ADD (array, i, __wmemset_chk,
>> + HAS_ARCH_FEATURE (AVX512F_Usable),
>> + __wmemset_chk_avx512_unaligned))
>> #endif
>>
>> return i;
>> diff --git a/sysdeps/x86_64/multiarch/memset-avx2-unaligned-erms.S
>>b/sysdeps/x86_64/multiarch/memset-avx2-unaligned-erms.S
>> index 79975e0..7ab3d89 100644
>> --- a/sysdeps/x86_64/multiarch/memset-avx2-unaligned-erms.S
>> +++ b/sysdeps/x86_64/multiarch/memset-avx2-unaligned-erms.S
>> @@ -4,13 +4,19 @@
>> # define VMOVU vmovdqu
>> # define VMOVA vmovdqa
>>
>> -# define VDUP_TO_VEC0_AND_SET_RETURN(d, r) \
>> +# define MEMSET_VDUP_TO_VEC0_AND_SET_RETURN(d, r) \
>> vmovd d, %xmm0; \
>> movq r, %rax; \
>> vpbroadcastb %xmm0, %ymm0
>>
>> +# define WMEMSET_VDUP_TO_VEC0_AND_SET_RETURN(d, r) \
>> + vmovd d, %xmm0; \
>> + movq r, %rax; \
>> + vpbroadcastd %xmm0, %ymm0
>> +
>> # define SECTION(p) p##.avx
>> # define MEMSET_SYMBOL(p,s) p##_avx2_##s
>> +# define WMEMSET_SYMBOL(p,s) p##_avx2_##s
>>
>> # include "memset-vec-unaligned-erms.S"
>> #endif
>> diff --git a/sysdeps/x86_64/multiarch/memset-avx512-unaligned-erms.S
>>b/sysdeps/x86_64/multiarch/memset-avx512-unaligned-erms.S
>> index a5ec349..0783979 100644
>> --- a/sysdeps/x86_64/multiarch/memset-avx512-unaligned-erms.S
>> +++ b/sysdeps/x86_64/multiarch/memset-avx512-unaligned-erms.S
>> @@ -4,14 +4,21 @@
>> # define VMOVU vmovdqu64
>> # define VMOVA vmovdqa64
>>
>> -# define VDUP_TO_VEC0_AND_SET_RETURN(d, r) \
>> +# define MEMSET_VDUP_TO_VEC0_AND_SET_RETURN(d, r) \
>> vmovd d, %xmm0; \
>> movq r, %rax; \
>> vpbroadcastb %xmm0, %xmm0; \
>> vpbroadcastq %xmm0, %zmm0
>>
>> +# define WMEMSET_VDUP_TO_VEC0_AND_SET_RETURN(d, r) \
>> + vmovd d, %xmm0; \
>> + movq r, %rax; \
>> + vpbroadcastd %xmm0, %xmm0; \
>> + vpbroadcastq %xmm0, %zmm0
>> +
>> # define SECTION(p) p##.avx512
>> # define MEMSET_SYMBOL(p,s) p##_avx512_##s
>> +# define WMEMSET_SYMBOL(p,s) p##_avx512_##s
>>
>> # include "memset-vec-unaligned-erms.S"
>> #endif
>> diff --git a/sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S
>>b/sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S
>> index 704eed9..2eb9e37 100644
>> --- a/sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S
>> +++ b/sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S
>> @@ -30,6 +30,10 @@
>> # define MEMSET_CHK_SYMBOL(p,s) MEMSET_SYMBOL(p, s)
>> #endif
>>
>> +#ifndef WMEMSET_CHK_SYMBOL
>> +# define WMEMSET_CHK_SYMBOL(p,s) WMEMSET_SYMBOL(p, s)
>> +#endif
>> +
>> #ifndef VZEROUPPER
>> # if VEC_SIZE > 16
>> # define VZEROUPPER vzeroupper
>> @@ -79,6 +83,21 @@ END (__bzero)
>> weak_alias (__bzero, bzero)
>> #endif
>>
>> +#if IS_IN (libc)
>> +# if defined SHARED
>> +ENTRY_CHK (WMEMSET_CHK_SYMBOL (__wmemset_chk, unaligned))
>> + cmpq %rdx, %rcx
>> + jb HIDDEN_JUMPTARGET (__chk_fail)
>> +END_CHK (WMEMSET_CHK_SYMBOL (__wmemset_chk, unaligned))
>> +# endif
>> +
>> +ENTRY (WMEMSET_SYMBOL (__wmemset, unaligned))
>> + shlq $2, %rdx
>> + WMEMSET_VDUP_TO_VEC0_AND_SET_RETURN (%esi, %rdi)
>> + jmp L(entry_from_bzero)
>> +END (WMEMSET_SYMBOL (__wmemset, unaligned))
>> +#endif
>> +
>> #if defined SHARED && IS_IN (libc)
>> ENTRY_CHK (MEMSET_CHK_SYMBOL (__memset_chk, unaligned))
>> cmpq %rdx, %rcx
>> @@ -87,8 +106,7 @@ END_CHK (MEMSET_CHK_SYMBOL (__memset_chk, unaligned))
>> #endif
>>
>> ENTRY (MEMSET_SYMBOL (__memset, unaligned))
>> -L(memset_entry):
>> - VDUP_TO_VEC0_AND_SET_RETURN (%esi, %rdi)
>> + MEMSET_VDUP_TO_VEC0_AND_SET_RETURN (%esi, %rdi)
>> L(entry_from_bzero):
>> cmpq $VEC_SIZE, %rdx
>> jb L(less_vec)
>> @@ -132,7 +150,7 @@ END_CHK (MEMSET_CHK_SYMBOL (__memset_chk,
>>unaligned_erms))
>> # endif
>>
>> ENTRY (MEMSET_SYMBOL (__memset, unaligned_erms))
>> - VDUP_TO_VEC0_AND_SET_RETURN (%esi, %rdi)
>> + MEMSET_VDUP_TO_VEC0_AND_SET_RETURN (%esi, %rdi)
>> cmpq $VEC_SIZE, %rdx
>> jb L(less_vec)
>> cmpq $(VEC_SIZE * 2), %rdx
>> diff --git a/sysdeps/x86_64/multiarch/memset.S
>>b/sysdeps/x86_64/multiarch/memset.S
>> index 9d33118..11f2737 100644
>> --- a/sysdeps/x86_64/multiarch/memset.S
>> +++ b/sysdeps/x86_64/multiarch/memset.S
>> @@ -58,16 +58,23 @@ END(memset)
>>
>> #if IS_IN (libc)
>> # define MEMSET_SYMBOL(p,s) p##_sse2_##s
>> +# define WMEMSET_SYMBOL(p,s) p##_sse2_##s
>>
>> # ifdef SHARED
>> -# undef libc_hidden_builtin_def
>> +# undef libc_hidden_builtin_def
>> /* It doesn't make sense to send libc-internal memset calls through a
>>PLT.
>> The speedup we get from using SSE2 instructions is likely eaten away
>> by the indirect call in the PLT. */
>> -# define libc_hidden_builtin_def(name) \
>> - .globl __GI_memset; __GI_memset = __memset_sse2_unaligned
>> +# define libc_hidden_builtin_def(name) \
>> + .globl __GI_memset; __GI_memset = __memset_sse2_unaligned; \
>> + .globl __GI_wmemset; __GI_wmemset = __wmemset_sse2_unaligned; \
>> + .globl __GI___wmemset; __GI___wmemset = __wmemset_sse2_unaligned
>> # endif
>>
>> +# undef weak_alias
>> +# define weak_alias(original, alias) \
>> + .weak bzero; bzero = __bzero
>> +
>> # undef strong_alias
>> # define strong_alias(original, alias)
>> #endif
>> diff --git a/sysdeps/x86_64/multiarch/wmemset.S
>>b/sysdeps/x86_64/multiarch/wmemset.S
>> new file mode 100644
>> index 0000000..3bd7ca2
>> --- /dev/null
>> +++ b/sysdeps/x86_64/multiarch/wmemset.S
>> @@ -0,0 +1,47 @@
>> +/* Multiple versions of wmemset
>> + All versions must be listed in ifunc-impl-list.c.
>> + Copyright (C) 2017 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
>> + <http://www.gnu.org/licenses/>. */
>> +
>> +/* Define multiple versions only for the definition in libc. */
>> +#if IS_IN (libc)
>> +
>> +#include <sysdep.h>
>> +#include <shlib-compat.h>
>> +#include <init-arch.h>
>> +
>> +ENTRY(__wmemset)
>> + .type __wmemset, @gnu_indirect_function
>> + LOAD_RTLD_GLOBAL_RO_RDX
>> + lea __wmemset_sse2_unaligned(%rip), %RAX_LP
>> + HAS_ARCH_FEATURE (Prefer_No_VZEROUPPER)
>> + jnz 1f
>> + HAS_ARCH_FEATURE (AVX_Fast_Unaligned_Load)
>> + jz 1f
>> + HAS_ARCH_FEATURE (AVX2_Usable)
>> + jz 1f
>> + lea __wmemset_avx2_unaligned(%rip), %RAX_LP
>> + HAS_ARCH_FEATURE (Prefer_No_AVX512)
>> + jnz 1f
>> + HAS_ARCH_FEATURE (AVX512F_Usable)
>> + jz 1f
>> + lea __wmemset_avx512_unaligned(%rip), %RAX_LP
>> +1: ret
>> +END(__wmemset)
>> +
>> +weak_alias (__wmemset, wmemset)
>> +#endif
>> diff --git a/sysdeps/x86_64/multiarch/wmemset_chk.S
>>b/sysdeps/x86_64/multiarch/wmemset_chk.S
>> new file mode 100644
>> index 0000000..c76fcb1
>> --- /dev/null
>> +++ b/sysdeps/x86_64/multiarch/wmemset_chk.S
>> @@ -0,0 +1,46 @@
>> +/* Multiple versions of wmemset_chk
>> + All versions must be listed in ifunc-impl-list.c.
>> + Copyright (C) 2017 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
>> + <http://www.gnu.org/licenses/>. */
>> +
>> +#include <sysdep.h>
>> +#include <shlib-compat.h>
>> +#include <init-arch.h>
>> +
>> +/* Define multiple versions only for the definition in libc. */
>> +#if IS_IN (libc)
>> +# ifdef SHARED
>> +ENTRY(__wmemset_chk)
>> + .type __wmemset_chk, @gnu_indirect_function
>> + LOAD_RTLD_GLOBAL_RO_RDX
>> + lea __wmemset_chk_sse2_unaligned(%rip), %RAX_LP
>> + HAS_ARCH_FEATURE (AVX2_Usable)
>> + jz 1f
>> + lea __wmemset_chk_avx2_unaligned(%rip), %RAX_LP
>> + HAS_ARCH_FEATURE (Prefer_No_AVX512)
>> + jnz 1f
>> + HAS_ARCH_FEATURE (Prefer_No_VZEROUPPER)
>> + jnz 1f
>> + HAS_ARCH_FEATURE (AVX512F_Usable)
>> + jz 1f
>> + lea __wmemset_chk_avx512_unaligned(%rip), %RAX_LP
>> +1: ret
>> +END(__wmemset_chk)
>> +# else
>> +# include "../wmemset_chk.S"
>> +# endif
>> +#endif
>> diff --git a/sysdeps/x86_64/wmemset.S b/sysdeps/x86_64/wmemset.S
>> new file mode 100644
>> index 0000000..f96d567
>> --- /dev/null
>> +++ b/sysdeps/x86_64/wmemset.S
>> @@ -0,0 +1 @@
>> +/* Implemented in memset.S. */
>> diff --git a/sysdeps/x86_64/wmemset_chk.S b/sysdeps/x86_64/wmemset_chk.S
>> new file mode 100644
>> index 0000000..64c2774
>> --- /dev/null
>> +++ b/sysdeps/x86_64/wmemset_chk.S
>> @@ -0,0 +1,33 @@
>> +/* Checking wmemset for x86-64.
>> + Copyright (C) 2004-2017 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
>> + <http://www.gnu.org/licenses/>. */
>> +
>> +#include <sysdep.h>
>> +#include "asm-syntax.h"
>> +
>> +#ifndef SHARED
>> + /* For libc.so this is defined in wmemset.S.
>> + For libc.a, this is a separate source to avoid
>> + wmemset bringing in __chk_fail and all routines
>> + it calls. */
>> + .text
>> +ENTRY (__wmemset_chk)
>> + cmpq %rdx, %rcx
>> + jb __chk_fail
>> + jmp wmemset
>> +END (__wmemset_chk)
>> +#endif
>> --
>> 2.9.4
>>
>
>
>
>--
>H.J.