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6d18a93dbb
No bug.
Optimization are
1. change control flow for L(more_2x_vec) to fall through to loop and
jump for L(less_4x_vec) and L(less_8x_vec). This uses less code
size and saves jumps for length > 4x VEC_SIZE.
2. For EVEX/AVX512 move L(less_vec) closer to entry.
3. Avoid complex address mode for length > 2x VEC_SIZE
4. Slightly better aligning code for the loop from the perspective of
code size and uops.
5. Align targets so they make full use of their fetch block and if
possible cache line.
6. Try and reduce total number of icache lines that will need to be
pulled in for a given length.
7. Include "local" version of stosb target. For AVX2/EVEX/AVX512
jumping to the stosb target in the sse2 code section will almost
certainly be to a new page. The new version does increase code size
marginally by duplicating the target but should get better iTLB
behavior as a result.
test-memset, test-wmemset, and test-bzero are all passing.
Signed-off-by: Noah Goldstein <goldstein.w.n@gmail.com>
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
(cherry picked from commit e59ced2384)
64 lines
1.7 KiB
ArmAsm
64 lines
1.7 KiB
ArmAsm
/* memset/bzero -- set memory area to CH/0
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Optimized version for x86-64.
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Copyright (C) 2002-2021 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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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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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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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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#include <sysdep.h>
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#define USE_WITH_SSE2 1
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#define VEC_SIZE 16
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#define MOV_SIZE 3
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#define RET_SIZE 1
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#define VEC(i) xmm##i
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#define VMOVU movups
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#define VMOVA movaps
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#define MEMSET_VDUP_TO_VEC0_AND_SET_RETURN(d, r) \
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movd d, %xmm0; \
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movq r, %rax; \
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punpcklbw %xmm0, %xmm0; \
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punpcklwd %xmm0, %xmm0; \
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pshufd $0, %xmm0, %xmm0
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#define WMEMSET_VDUP_TO_VEC0_AND_SET_RETURN(d, r) \
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movd d, %xmm0; \
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movq r, %rax; \
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pshufd $0, %xmm0, %xmm0
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#define SECTION(p) p
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#ifndef MEMSET_SYMBOL
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# define MEMSET_CHK_SYMBOL(p,s) p
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# define MEMSET_SYMBOL(p,s) memset
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#endif
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#ifndef WMEMSET_SYMBOL
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# define WMEMSET_CHK_SYMBOL(p,s) p
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# define WMEMSET_SYMBOL(p,s) __wmemset
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#endif
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#include "multiarch/memset-vec-unaligned-erms.S"
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libc_hidden_builtin_def (memset)
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#if IS_IN (libc)
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libc_hidden_def (__wmemset)
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weak_alias (__wmemset, wmemset)
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libc_hidden_weak (wmemset)
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#endif
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