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https://sourceware.org/git/glibc.git
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3f4b61a0b8
Add x86_rep_movsb_threshold and x86_rep_stosb_threshold to tunables to update thresholds for "rep movsb" and "rep stosb" at run-time. Note that the user specified threshold for "rep movsb" smaller than the minimum threshold will be ignored. Reviewed-by: Carlos O'Donell <carlos@redhat.com>
273 lines
6.6 KiB
ArmAsm
273 lines
6.6 KiB
ArmAsm
/* memset/bzero with unaligned store and rep stosb
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Copyright (C) 2016-2020 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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/* memset is implemented as:
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1. Use overlapping store to avoid branch.
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2. If size is less than VEC, use integer register stores.
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3. If size is from VEC_SIZE to 2 * VEC_SIZE, use 2 VEC stores.
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4. If size is from 2 * VEC_SIZE to 4 * VEC_SIZE, use 4 VEC stores.
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5. If size is more to 4 * VEC_SIZE, align to 4 * VEC_SIZE with
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4 VEC stores and store 4 * VEC at a time until done. */
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#include <sysdep.h>
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#ifndef MEMSET_CHK_SYMBOL
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# define MEMSET_CHK_SYMBOL(p,s) MEMSET_SYMBOL(p, s)
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#endif
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#ifndef WMEMSET_CHK_SYMBOL
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# define WMEMSET_CHK_SYMBOL(p,s) WMEMSET_SYMBOL(p, s)
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#endif
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#ifndef VZEROUPPER
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# if VEC_SIZE > 16
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# define VZEROUPPER vzeroupper
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# else
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# define VZEROUPPER
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# endif
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#endif
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#ifndef VZEROUPPER_SHORT_RETURN
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# if VEC_SIZE > 16
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# define VZEROUPPER_SHORT_RETURN vzeroupper
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# else
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# define VZEROUPPER_SHORT_RETURN rep
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# endif
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#endif
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#ifndef MOVQ
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# if VEC_SIZE > 16
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# define MOVQ vmovq
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# else
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# define MOVQ movq
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# endif
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#endif
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#ifndef SECTION
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# error SECTION is not defined!
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#endif
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.section SECTION(.text),"ax",@progbits
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#if VEC_SIZE == 16 && IS_IN (libc)
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ENTRY (__bzero)
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mov %RDI_LP, %RAX_LP /* Set return value. */
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mov %RSI_LP, %RDX_LP /* Set n. */
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pxor %xmm0, %xmm0
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jmp L(entry_from_bzero)
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END (__bzero)
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weak_alias (__bzero, bzero)
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#endif
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#if IS_IN (libc)
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# if defined SHARED
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ENTRY_CHK (WMEMSET_CHK_SYMBOL (__wmemset_chk, unaligned))
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cmp %RDX_LP, %RCX_LP
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jb HIDDEN_JUMPTARGET (__chk_fail)
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END_CHK (WMEMSET_CHK_SYMBOL (__wmemset_chk, unaligned))
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# endif
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ENTRY (WMEMSET_SYMBOL (__wmemset, unaligned))
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shl $2, %RDX_LP
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WMEMSET_VDUP_TO_VEC0_AND_SET_RETURN (%esi, %rdi)
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jmp L(entry_from_bzero)
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END (WMEMSET_SYMBOL (__wmemset, unaligned))
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#endif
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#if defined SHARED && IS_IN (libc)
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ENTRY_CHK (MEMSET_CHK_SYMBOL (__memset_chk, unaligned))
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cmp %RDX_LP, %RCX_LP
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jb HIDDEN_JUMPTARGET (__chk_fail)
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END_CHK (MEMSET_CHK_SYMBOL (__memset_chk, unaligned))
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#endif
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ENTRY (MEMSET_SYMBOL (__memset, unaligned))
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MEMSET_VDUP_TO_VEC0_AND_SET_RETURN (%esi, %rdi)
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# ifdef __ILP32__
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/* Clear the upper 32 bits. */
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mov %edx, %edx
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# endif
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L(entry_from_bzero):
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cmpq $VEC_SIZE, %rdx
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jb L(less_vec)
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cmpq $(VEC_SIZE * 2), %rdx
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ja L(more_2x_vec)
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/* From VEC and to 2 * VEC. No branch when size == VEC_SIZE. */
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VMOVU %VEC(0), -VEC_SIZE(%rdi,%rdx)
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VMOVU %VEC(0), (%rdi)
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VZEROUPPER
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ret
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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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/* 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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/* Issue vzeroupper before rep stosb. */
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VZEROUPPER
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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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# 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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# 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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jb HIDDEN_JUMPTARGET (__chk_fail)
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END_CHK (MEMSET_CHK_SYMBOL (__memset_chk, unaligned_erms))
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# endif
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ENTRY (MEMSET_SYMBOL (__memset, unaligned_erms))
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MEMSET_VDUP_TO_VEC0_AND_SET_RETURN (%esi, %rdi)
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# ifdef __ILP32__
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/* Clear the upper 32 bits. */
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mov %edx, %edx
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# endif
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cmp $VEC_SIZE, %RDX_LP
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jb L(less_vec)
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cmp $(VEC_SIZE * 2), %RDX_LP
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ja L(stosb_more_2x_vec)
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/* From VEC and to 2 * VEC. No branch when size == VEC_SIZE. */
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VMOVU %VEC(0), -VEC_SIZE(%rdi,%rdx)
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VMOVU %VEC(0), (%rdi)
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VZEROUPPER
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ret
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L(stosb_more_2x_vec):
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cmp __x86_rep_stosb_threshold(%rip), %RDX_LP
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ja L(stosb)
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#endif
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L(more_2x_vec):
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cmpq $(VEC_SIZE * 4), %rdx
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ja L(loop_start)
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VMOVU %VEC(0), (%rdi)
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VMOVU %VEC(0), VEC_SIZE(%rdi)
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VMOVU %VEC(0), -VEC_SIZE(%rdi,%rdx)
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VMOVU %VEC(0), -(VEC_SIZE * 2)(%rdi,%rdx)
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L(return):
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VZEROUPPER
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ret
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L(loop_start):
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leaq (VEC_SIZE * 4)(%rdi), %rcx
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VMOVU %VEC(0), (%rdi)
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andq $-(VEC_SIZE * 4), %rcx
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VMOVU %VEC(0), -VEC_SIZE(%rdi,%rdx)
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VMOVU %VEC(0), VEC_SIZE(%rdi)
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VMOVU %VEC(0), -(VEC_SIZE * 2)(%rdi,%rdx)
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VMOVU %VEC(0), (VEC_SIZE * 2)(%rdi)
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VMOVU %VEC(0), -(VEC_SIZE * 3)(%rdi,%rdx)
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VMOVU %VEC(0), (VEC_SIZE * 3)(%rdi)
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VMOVU %VEC(0), -(VEC_SIZE * 4)(%rdi,%rdx)
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addq %rdi, %rdx
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andq $-(VEC_SIZE * 4), %rdx
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cmpq %rdx, %rcx
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je L(return)
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L(loop):
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VMOVA %VEC(0), (%rcx)
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VMOVA %VEC(0), VEC_SIZE(%rcx)
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VMOVA %VEC(0), (VEC_SIZE * 2)(%rcx)
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VMOVA %VEC(0), (VEC_SIZE * 3)(%rcx)
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addq $(VEC_SIZE * 4), %rcx
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cmpq %rcx, %rdx
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jne L(loop)
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VZEROUPPER_SHORT_RETURN
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ret
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L(less_vec):
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/* Less than 1 VEC. */
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# if VEC_SIZE != 16 && VEC_SIZE != 32 && VEC_SIZE != 64
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# error Unsupported VEC_SIZE!
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# endif
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# if VEC_SIZE > 32
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cmpb $32, %dl
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jae L(between_32_63)
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# endif
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# if VEC_SIZE > 16
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cmpb $16, %dl
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jae L(between_16_31)
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# endif
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MOVQ %xmm0, %rcx
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cmpb $8, %dl
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jae L(between_8_15)
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cmpb $4, %dl
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jae L(between_4_7)
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cmpb $1, %dl
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ja L(between_2_3)
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jb 1f
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movb %cl, (%rdi)
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1:
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VZEROUPPER
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ret
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# if VEC_SIZE > 32
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/* From 32 to 63. No branch when size == 32. */
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L(between_32_63):
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vmovdqu %ymm0, -32(%rdi,%rdx)
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vmovdqu %ymm0, (%rdi)
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VZEROUPPER
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ret
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# endif
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# if VEC_SIZE > 16
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/* From 16 to 31. No branch when size == 16. */
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L(between_16_31):
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vmovdqu %xmm0, -16(%rdi,%rdx)
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vmovdqu %xmm0, (%rdi)
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VZEROUPPER
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ret
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# endif
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/* From 8 to 15. No branch when size == 8. */
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L(between_8_15):
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movq %rcx, -8(%rdi,%rdx)
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movq %rcx, (%rdi)
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VZEROUPPER
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ret
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L(between_4_7):
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/* From 4 to 7. No branch when size == 4. */
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movl %ecx, -4(%rdi,%rdx)
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movl %ecx, (%rdi)
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VZEROUPPER
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ret
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L(between_2_3):
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/* From 2 to 3. No branch when size == 2. */
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movw %cx, -2(%rdi,%rdx)
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movw %cx, (%rdi)
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VZEROUPPER
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ret
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END (MEMSET_SYMBOL (__memset, unaligned_erms))
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