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124 lines
3.9 KiB
124 lines
3.9 KiB
commit 7079931c51547854323fe2ed6fdccf2a1b8b04d7 |
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Author: Noah Goldstein <goldstein.w.n@gmail.com> |
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Date: Wed Jun 29 16:07:05 2022 -0700 |
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x86: Move and slightly improve memset_erms |
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Implementation wise: |
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1. Remove the VZEROUPPER as memset_{impl}_unaligned_erms does not |
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use the L(stosb) label that was previously defined. |
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2. Don't give the hotpath (fallthrough) to zero size. |
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Code positioning wise: |
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Move memset_{chk}_erms to its own file. Leaving it in between the |
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memset_{impl}_unaligned both adds unnecessary complexity to the |
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file and wastes space in a relatively hot cache section. |
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(cherry picked from commit 4a3f29e7e475dd4e7cce2a24c187e6fb7b5b0a05) |
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diff --git a/sysdeps/x86_64/multiarch/Makefile b/sysdeps/x86_64/multiarch/Makefile |
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index 0e39e63ef6be6a86..da9f16286a763556 100644 |
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--- a/sysdeps/x86_64/multiarch/Makefile |
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+++ b/sysdeps/x86_64/multiarch/Makefile |
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@@ -29,6 +29,7 @@ sysdep_routines += \ |
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memset-avx2-unaligned-erms-rtm \ |
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memset-avx512-no-vzeroupper \ |
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memset-avx512-unaligned-erms \ |
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+ memset-erms \ |
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memset-evex-unaligned-erms \ |
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memset-sse2-unaligned-erms \ |
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rawmemchr-avx2 \ |
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diff --git a/sysdeps/x86_64/multiarch/memset-erms.S b/sysdeps/x86_64/multiarch/memset-erms.S |
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new file mode 100644 |
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index 0000000000000000..e83cccc731f0a7ea |
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--- /dev/null |
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+++ b/sysdeps/x86_64/multiarch/memset-erms.S |
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@@ -0,0 +1,44 @@ |
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+/* memset implement with rep stosb |
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+ Copyright (C) 2022 Free Software Foundation, Inc. |
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+ This file is part of the GNU C Library. |
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+ |
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+ The GNU C Library is free software; you can redistribute it and/or |
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+ modify it under the terms of the GNU Lesser General Public |
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+ License as published by the Free Software Foundation; either |
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+ version 2.1 of the License, or (at your option) any later version. |
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+ |
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+ The GNU C Library is distributed in the hope that it will be useful, |
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+ but WITHOUT ANY WARRANTY; without even the implied warranty of |
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+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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+ Lesser General Public License for more details. |
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+ |
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+ You should have received a copy of the GNU Lesser General Public |
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+ License along with the GNU C Library; if not, see |
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+ <https://www.gnu.org/licenses/>. */ |
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+ |
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+ |
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+#include <sysdep.h> |
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+ |
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+#if defined USE_MULTIARCH && IS_IN (libc) |
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+ .text |
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+ENTRY (__memset_chk_erms) |
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+ cmp %RDX_LP, %RCX_LP |
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+ jb HIDDEN_JUMPTARGET (__chk_fail) |
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+END (__memset_chk_erms) |
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+ |
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+/* Only used to measure performance of REP STOSB. */ |
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+ENTRY (__memset_erms) |
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+ /* Skip zero length. */ |
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+ test %RDX_LP, %RDX_LP |
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+ jz L(stosb_return_zero) |
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+ mov %RDX_LP, %RCX_LP |
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+ movzbl %sil, %eax |
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+ mov %RDI_LP, %RDX_LP |
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+ rep stosb |
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+ mov %RDX_LP, %RAX_LP |
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+ ret |
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+L(stosb_return_zero): |
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+ movq %rdi, %rax |
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+ ret |
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+END (__memset_erms) |
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+#endif |
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diff --git a/sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S b/sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S |
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index abc12d9cda1b3843..905d0fa4643d5768 100644 |
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--- a/sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S |
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+++ b/sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S |
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@@ -156,37 +156,6 @@ L(entry_from_wmemset): |
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#if defined USE_MULTIARCH && IS_IN (libc) |
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END (MEMSET_SYMBOL (__memset, unaligned)) |
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-# if VEC_SIZE == 16 |
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-ENTRY (__memset_chk_erms) |
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- cmp %RDX_LP, %RCX_LP |
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- jb HIDDEN_JUMPTARGET (__chk_fail) |
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-END (__memset_chk_erms) |
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- |
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-/* Only used to measure performance of REP STOSB. */ |
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-ENTRY (__memset_erms) |
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- /* Skip zero length. */ |
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- test %RDX_LP, %RDX_LP |
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- jnz L(stosb) |
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- movq %rdi, %rax |
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- ret |
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-# else |
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-/* Provide a hidden symbol to debugger. */ |
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- .hidden MEMSET_SYMBOL (__memset, erms) |
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-ENTRY (MEMSET_SYMBOL (__memset, erms)) |
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-# endif |
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-L(stosb): |
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- mov %RDX_LP, %RCX_LP |
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- movzbl %sil, %eax |
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- mov %RDI_LP, %RDX_LP |
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- rep stosb |
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- mov %RDX_LP, %RAX_LP |
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- VZEROUPPER_RETURN |
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-# if VEC_SIZE == 16 |
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-END (__memset_erms) |
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-# else |
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-END (MEMSET_SYMBOL (__memset, erms)) |
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-# endif |
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- |
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# if defined SHARED && IS_IN (libc) |
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ENTRY_CHK (MEMSET_CHK_SYMBOL (__memset_chk, unaligned_erms)) |
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cmp %RDX_LP, %RCX_LP
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