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https://sourceware.org/git/glibc.git
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dc485ceb2a
Optimize strlen/strnlen/wcslen/wcsnlen with AVX2 to check 32 bytes with a single vector compare instruction. It is as fast as SSE2 versions for size <= 16 bytes and up to 1X faster for or size > 16 bytes on Haswell. Select AVX2 version on AVX2 machines where vzeroupper is preferred and AVX unaligned load is fast. NB: It uses TZCNT instead of BSF since TZCNT produces the same result as BSF for non-zero input. TZCNT is faster than BSF and is executed as BSF if machine doesn't support TZCNT. * sysdeps/x86_64/multiarch/Makefile (sysdep_routines): Add strlen-sse2, strnlen-sse2, strlen-avx2, strnlen-avx2, wcslen-sse2, wcslen-avx2 and wcsnlen-avx2. * sysdeps/x86_64/multiarch/ifunc-impl-list.c (__libc_ifunc_impl_list): Add tests for __strlen_avx2, __strlen_sse2, __strnlen_avx2, __strnlen_sse2, __wcslen_avx2, __wcslen_sse2 and __wcsnlen_avx2. * sysdeps/x86_64/multiarch/strlen-avx2.S: New file. * sysdeps/x86_64/multiarch/strlen-sse2.S: Likewise. * sysdeps/x86_64/multiarch/strlen.c: Likewise. * sysdeps/x86_64/multiarch/strnlen-avx2.S: Likewise. * sysdeps/x86_64/multiarch/strnlen-sse2.S: Likewise. * sysdeps/x86_64/multiarch/strnlen.c: Likewise. * sysdeps/x86_64/multiarch/wcslen-avx2.S: Likewise. * sysdeps/x86_64/multiarch/wcslen-sse2.S: Likewise. * sysdeps/x86_64/multiarch/wcslen.c: Likewise. * sysdeps/x86_64/multiarch/wcsnlen-avx2.S: Likewise. * sysdeps/x86_64/multiarch/wcsnlen.c (OPTIMIZE (avx2)): New. (IFUNC_SELECTOR): Return OPTIMIZE (avx2) on AVX2 machines where vzeroupper is preferred and AVX unaligned load is fast.
395 lines
7.4 KiB
ArmAsm
395 lines
7.4 KiB
ArmAsm
/* strlen/strnlen/wcslen/wcsnlen optimized with AVX2.
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Copyright (C) 2017 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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<http://www.gnu.org/licenses/>. */
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#if IS_IN (libc)
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# include <sysdep.h>
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# ifndef STRLEN
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# define STRLEN __strlen_avx2
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# endif
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# ifdef USE_AS_WCSLEN
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# define VPCMPEQ vpcmpeqd
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# define VPMINU vpminud
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# else
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# define VPCMPEQ vpcmpeqb
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# define VPMINU vpminub
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# endif
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# ifndef VZEROUPPER
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# define VZEROUPPER vzeroupper
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# endif
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# define VEC_SIZE 32
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.section .text.avx,"ax",@progbits
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ENTRY (STRLEN)
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# ifdef USE_AS_STRNLEN
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/* Check for zero length. */
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testq %rsi, %rsi
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jz L(zero)
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# ifdef USE_AS_WCSLEN
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shl $2, %rsi
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# endif
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movq %rsi, %r8
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# endif
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movl %edi, %ecx
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movq %rdi, %rdx
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vpxor %xmm0, %xmm0, %xmm0
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/* Check if we may cross page boundary with one vector load. */
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andl $(2 * VEC_SIZE - 1), %ecx
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cmpl $VEC_SIZE, %ecx
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ja L(cros_page_boundary)
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/* Check the first VEC_SIZE bytes. */
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VPCMPEQ (%rdi), %ymm0, %ymm1
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vpmovmskb %ymm1, %eax
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testl %eax, %eax
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# ifdef USE_AS_STRNLEN
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jnz L(first_vec_x0_check)
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/* Adjust length and check the end of data. */
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subq $VEC_SIZE, %rsi
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jbe L(max)
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# else
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jnz L(first_vec_x0)
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# endif
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/* Align data for aligned loads in the loop. */
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addq $VEC_SIZE, %rdi
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andl $(VEC_SIZE - 1), %ecx
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andq $-VEC_SIZE, %rdi
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# ifdef USE_AS_STRNLEN
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/* Adjust length. */
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addq %rcx, %rsi
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subq $(VEC_SIZE * 4), %rsi
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jbe L(last_4x_vec_or_less)
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# endif
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jmp L(more_4x_vec)
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.p2align 4
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L(cros_page_boundary):
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andl $(VEC_SIZE - 1), %ecx
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andq $-VEC_SIZE, %rdi
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VPCMPEQ (%rdi), %ymm0, %ymm1
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vpmovmskb %ymm1, %eax
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/* Remove the leading bytes. */
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sarl %cl, %eax
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testl %eax, %eax
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jz L(aligned_more)
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tzcntl %eax, %eax
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# ifdef USE_AS_STRNLEN
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/* Check the end of data. */
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cmpq %rax, %rsi
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jbe L(max)
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# endif
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addq %rdi, %rax
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addq %rcx, %rax
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subq %rdx, %rax
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# ifdef USE_AS_WCSLEN
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shrq $2, %rax
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# endif
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VZEROUPPER
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ret
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.p2align 4
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L(aligned_more):
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# ifdef USE_AS_STRNLEN
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/* "rcx" is less than VEC_SIZE. Calculate "rdx + rcx - VEC_SIZE"
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with "rdx - (VEC_SIZE - rcx)" instead of "(rdx + rcx) - VEC_SIZE"
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to void possible addition overflow. */
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negq %rcx
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addq $VEC_SIZE, %rcx
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/* Check the end of data. */
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subq %rcx, %rsi
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jbe L(max)
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# endif
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addq $VEC_SIZE, %rdi
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# ifdef USE_AS_STRNLEN
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subq $(VEC_SIZE * 4), %rsi
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jbe L(last_4x_vec_or_less)
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# endif
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L(more_4x_vec):
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/* Check the first 4 * VEC_SIZE. Only one VEC_SIZE at a time
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since data is only aligned to VEC_SIZE. */
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VPCMPEQ (%rdi), %ymm0, %ymm1
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vpmovmskb %ymm1, %eax
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testl %eax, %eax
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jnz L(first_vec_x0)
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VPCMPEQ VEC_SIZE(%rdi), %ymm0, %ymm1
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vpmovmskb %ymm1, %eax
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testl %eax, %eax
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jnz L(first_vec_x1)
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VPCMPEQ (VEC_SIZE * 2)(%rdi), %ymm0, %ymm1
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vpmovmskb %ymm1, %eax
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testl %eax, %eax
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jnz L(first_vec_x2)
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VPCMPEQ (VEC_SIZE * 3)(%rdi), %ymm0, %ymm1
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vpmovmskb %ymm1, %eax
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testl %eax, %eax
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jnz L(first_vec_x3)
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addq $(VEC_SIZE * 4), %rdi
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# ifdef USE_AS_STRNLEN
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subq $(VEC_SIZE * 4), %rsi
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jbe L(last_4x_vec_or_less)
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# endif
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/* Align data to 4 * VEC_SIZE. */
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movq %rdi, %rcx
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andl $(4 * VEC_SIZE - 1), %ecx
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andq $-(4 * VEC_SIZE), %rdi
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# ifdef USE_AS_STRNLEN
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/* Adjust length. */
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addq %rcx, %rsi
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# endif
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.p2align 4
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L(loop_4x_vec):
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/* Compare 4 * VEC at a time forward. */
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vmovdqa (%rdi), %ymm1
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vmovdqa VEC_SIZE(%rdi), %ymm2
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vmovdqa (VEC_SIZE * 2)(%rdi), %ymm3
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vmovdqa (VEC_SIZE * 3)(%rdi), %ymm4
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VPMINU %ymm1, %ymm2, %ymm5
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VPMINU %ymm3, %ymm4, %ymm6
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VPMINU %ymm5, %ymm6, %ymm5
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VPCMPEQ %ymm5, %ymm0, %ymm5
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vpmovmskb %ymm5, %eax
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testl %eax, %eax
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jnz L(4x_vec_end)
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addq $(VEC_SIZE * 4), %rdi
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# ifndef USE_AS_STRNLEN
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jmp L(loop_4x_vec)
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# else
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subq $(VEC_SIZE * 4), %rsi
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ja L(loop_4x_vec)
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L(last_4x_vec_or_less):
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/* Less than 4 * VEC and aligned to VEC_SIZE. */
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addl $(VEC_SIZE * 2), %esi
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jle L(last_2x_vec)
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VPCMPEQ (%rdi), %ymm0, %ymm1
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vpmovmskb %ymm1, %eax
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testl %eax, %eax
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jnz L(first_vec_x0)
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VPCMPEQ VEC_SIZE(%rdi), %ymm0, %ymm1
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vpmovmskb %ymm1, %eax
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testl %eax, %eax
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jnz L(first_vec_x1)
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VPCMPEQ (VEC_SIZE * 2)(%rdi), %ymm0, %ymm1
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vpmovmskb %ymm1, %eax
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testl %eax, %eax
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jnz L(first_vec_x2_check)
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subl $VEC_SIZE, %esi
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jle L(max)
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VPCMPEQ (VEC_SIZE * 3)(%rdi), %ymm0, %ymm1
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vpmovmskb %ymm1, %eax
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testl %eax, %eax
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jnz L(first_vec_x3_check)
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movq %r8, %rax
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# ifdef USE_AS_WCSLEN
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shrq $2, %rax
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# endif
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VZEROUPPER
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ret
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.p2align 4
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L(last_2x_vec):
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addl $(VEC_SIZE * 2), %esi
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VPCMPEQ (%rdi), %ymm0, %ymm1
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vpmovmskb %ymm1, %eax
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testl %eax, %eax
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jnz L(first_vec_x0_check)
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subl $VEC_SIZE, %esi
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jle L(max)
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VPCMPEQ VEC_SIZE(%rdi), %ymm0, %ymm1
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vpmovmskb %ymm1, %eax
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testl %eax, %eax
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jnz L(first_vec_x1_check)
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movq %r8, %rax
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# ifdef USE_AS_WCSLEN
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shrq $2, %rax
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# endif
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VZEROUPPER
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ret
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.p2align 4
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L(first_vec_x0_check):
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tzcntl %eax, %eax
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/* Check the end of data. */
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cmpq %rax, %rsi
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jbe L(max)
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addq %rdi, %rax
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subq %rdx, %rax
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# ifdef USE_AS_WCSLEN
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shrq $2, %rax
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# endif
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VZEROUPPER
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ret
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.p2align 4
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L(first_vec_x1_check):
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tzcntl %eax, %eax
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/* Check the end of data. */
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cmpq %rax, %rsi
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jbe L(max)
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addq $VEC_SIZE, %rax
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addq %rdi, %rax
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subq %rdx, %rax
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# ifdef USE_AS_WCSLEN
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shrq $2, %rax
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# endif
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VZEROUPPER
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ret
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.p2align 4
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L(first_vec_x2_check):
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tzcntl %eax, %eax
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/* Check the end of data. */
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cmpq %rax, %rsi
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jbe L(max)
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addq $(VEC_SIZE * 2), %rax
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addq %rdi, %rax
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subq %rdx, %rax
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# ifdef USE_AS_WCSLEN
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shrq $2, %rax
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# endif
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VZEROUPPER
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ret
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.p2align 4
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L(first_vec_x3_check):
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tzcntl %eax, %eax
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/* Check the end of data. */
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cmpq %rax, %rsi
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jbe L(max)
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addq $(VEC_SIZE * 3), %rax
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addq %rdi, %rax
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subq %rdx, %rax
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# ifdef USE_AS_WCSLEN
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shrq $2, %rax
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# endif
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VZEROUPPER
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ret
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.p2align 4
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L(max):
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movq %r8, %rax
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# ifdef USE_AS_WCSLEN
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shrq $2, %rax
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# endif
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VZEROUPPER
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ret
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.p2align 4
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L(zero):
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xorl %eax, %eax
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ret
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# endif
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.p2align 4
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L(first_vec_x0):
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tzcntl %eax, %eax
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addq %rdi, %rax
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subq %rdx, %rax
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# ifdef USE_AS_WCSLEN
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shrq $2, %rax
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# endif
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VZEROUPPER
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ret
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.p2align 4
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L(first_vec_x1):
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tzcntl %eax, %eax
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addq $VEC_SIZE, %rax
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addq %rdi, %rax
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subq %rdx, %rax
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# ifdef USE_AS_WCSLEN
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shrq $2, %rax
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# endif
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VZEROUPPER
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ret
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.p2align 4
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L(first_vec_x2):
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tzcntl %eax, %eax
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addq $(VEC_SIZE * 2), %rax
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addq %rdi, %rax
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subq %rdx, %rax
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# ifdef USE_AS_WCSLEN
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shrq $2, %rax
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# endif
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VZEROUPPER
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ret
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.p2align 4
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L(4x_vec_end):
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VPCMPEQ %ymm1, %ymm0, %ymm1
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vpmovmskb %ymm1, %eax
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testl %eax, %eax
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jnz L(first_vec_x0)
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VPCMPEQ %ymm2, %ymm0, %ymm2
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vpmovmskb %ymm2, %eax
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testl %eax, %eax
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jnz L(first_vec_x1)
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VPCMPEQ %ymm3, %ymm0, %ymm3
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vpmovmskb %ymm3, %eax
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testl %eax, %eax
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jnz L(first_vec_x2)
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VPCMPEQ %ymm4, %ymm0, %ymm4
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vpmovmskb %ymm4, %eax
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testl %eax, %eax
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L(first_vec_x3):
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tzcntl %eax, %eax
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addq $(VEC_SIZE * 3), %rax
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addq %rdi, %rax
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subq %rdx, %rax
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# ifdef USE_AS_WCSLEN
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shrq $2, %rax
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# endif
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VZEROUPPER
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ret
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END (STRLEN)
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#endif
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