863 lines
20 KiB
ArmAsm
863 lines
20 KiB
ArmAsm
/* strcmp/wcscmp/strncmp/wcsncmp optimized with AVX2.
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Copyright (C) 2018-2019 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 STRCMP
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# define STRCMP __strcmp_avx2
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# endif
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# define PAGE_SIZE 4096
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/* VEC_SIZE = Number of bytes in a ymm register */
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# define VEC_SIZE 32
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/* Shift for dividing by (VEC_SIZE * 4). */
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# define DIVIDE_BY_VEC_4_SHIFT 7
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# if (VEC_SIZE * 4) != (1 << DIVIDE_BY_VEC_4_SHIFT)
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# error (VEC_SIZE * 4) != (1 << DIVIDE_BY_VEC_4_SHIFT)
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# endif
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# ifdef USE_AS_WCSCMP
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/* Compare packed dwords. */
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# define VPCMPEQ vpcmpeqd
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/* Compare packed dwords and store minimum. */
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# define VPMINU vpminud
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/* 1 dword char == 4 bytes. */
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# define SIZE_OF_CHAR 4
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# else
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/* Compare packed bytes. */
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# define VPCMPEQ vpcmpeqb
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/* Compare packed bytes and store minimum. */
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# define VPMINU vpminub
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/* 1 byte char == 1 byte. */
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# define SIZE_OF_CHAR 1
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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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/* Warning!
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wcscmp/wcsncmp have to use SIGNED comparison for elements.
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strcmp/strncmp have to use UNSIGNED comparison for elements.
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*/
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/* The main idea of the string comparison (byte or dword) using AVX2
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consists of comparing (VPCMPEQ) two ymm vectors. The latter can be on
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either packed bytes or dwords depending on USE_AS_WCSCMP. In order
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to check the null char, algorithm keeps the matched bytes/dwords,
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requiring two more AVX2 instructions (VPMINU and VPCMPEQ). In general,
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the costs of comparing VEC_SIZE bytes (32-bytes) are two VPCMPEQ and
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one VPMINU instructions, together with movdqu and testl instructions.
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Main loop (away from from page boundary) compares 4 vectors are a time,
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effectively comparing 4 x VEC_SIZE bytes (128 bytes) on each loop.
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The routine strncmp/wcsncmp (enabled by defining USE_AS_STRNCMP) logic
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is the same as strcmp, except that an a maximum offset is tracked. If
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the maximum offset is reached before a difference is found, zero is
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returned. */
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.section .text.avx,"ax",@progbits
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ENTRY (STRCMP)
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# ifdef USE_AS_STRNCMP
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/* Check for simple cases (0 or 1) in offset. */
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cmp $1, %RDX_LP
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je L(char0)
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jb L(zero)
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# ifdef USE_AS_WCSCMP
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/* Convert units: from wide to byte char. */
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shl $2, %RDX_LP
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# endif
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/* Register %r11 tracks the maximum offset. */
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mov %RDX_LP, %R11_LP
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# endif
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movl %edi, %eax
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xorl %edx, %edx
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/* Make %ymm7 all zeros in this function. */
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vpxor %ymm7, %ymm7, %ymm7
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orl %esi, %eax
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andl $(PAGE_SIZE - 1), %eax
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cmpl $(PAGE_SIZE - (VEC_SIZE * 4)), %eax
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jg L(cross_page)
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/* Start comparing 4 vectors. */
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vmovdqu (%rdi), %ymm1
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VPCMPEQ (%rsi), %ymm1, %ymm0
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VPMINU %ymm1, %ymm0, %ymm0
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VPCMPEQ %ymm7, %ymm0, %ymm0
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vpmovmskb %ymm0, %ecx
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testl %ecx, %ecx
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je L(next_3_vectors)
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tzcntl %ecx, %edx
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# ifdef USE_AS_STRNCMP
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/* Return 0 if the mismatched index (%rdx) is after the maximum
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offset (%r11). */
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cmpq %r11, %rdx
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jae L(zero)
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# endif
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# ifdef USE_AS_WCSCMP
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xorl %eax, %eax
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movl (%rdi, %rdx), %ecx
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cmpl (%rsi, %rdx), %ecx
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je L(return)
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L(wcscmp_return):
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setl %al
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negl %eax
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orl $1, %eax
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L(return):
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# else
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movzbl (%rdi, %rdx), %eax
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movzbl (%rsi, %rdx), %edx
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subl %edx, %eax
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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(return_vec_size):
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tzcntl %ecx, %edx
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# ifdef USE_AS_STRNCMP
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/* Return 0 if the mismatched index (%rdx + VEC_SIZE) is after
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the maximum offset (%r11). */
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addq $VEC_SIZE, %rdx
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cmpq %r11, %rdx
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jae L(zero)
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# ifdef USE_AS_WCSCMP
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xorl %eax, %eax
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movl (%rdi, %rdx), %ecx
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cmpl (%rsi, %rdx), %ecx
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jne L(wcscmp_return)
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# else
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movzbl (%rdi, %rdx), %eax
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movzbl (%rsi, %rdx), %edx
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subl %edx, %eax
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# endif
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# else
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# ifdef USE_AS_WCSCMP
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xorl %eax, %eax
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movl VEC_SIZE(%rdi, %rdx), %ecx
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cmpl VEC_SIZE(%rsi, %rdx), %ecx
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jne L(wcscmp_return)
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# else
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movzbl VEC_SIZE(%rdi, %rdx), %eax
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movzbl VEC_SIZE(%rsi, %rdx), %edx
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subl %edx, %eax
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# endif
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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(return_2_vec_size):
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tzcntl %ecx, %edx
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# ifdef USE_AS_STRNCMP
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/* Return 0 if the mismatched index (%rdx + 2 * VEC_SIZE) is
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after the maximum offset (%r11). */
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addq $(VEC_SIZE * 2), %rdx
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cmpq %r11, %rdx
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jae L(zero)
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# ifdef USE_AS_WCSCMP
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xorl %eax, %eax
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movl (%rdi, %rdx), %ecx
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cmpl (%rsi, %rdx), %ecx
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jne L(wcscmp_return)
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# else
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movzbl (%rdi, %rdx), %eax
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movzbl (%rsi, %rdx), %edx
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subl %edx, %eax
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# endif
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# else
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# ifdef USE_AS_WCSCMP
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xorl %eax, %eax
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movl (VEC_SIZE * 2)(%rdi, %rdx), %ecx
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cmpl (VEC_SIZE * 2)(%rsi, %rdx), %ecx
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jne L(wcscmp_return)
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# else
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movzbl (VEC_SIZE * 2)(%rdi, %rdx), %eax
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movzbl (VEC_SIZE * 2)(%rsi, %rdx), %edx
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subl %edx, %eax
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# endif
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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(return_3_vec_size):
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tzcntl %ecx, %edx
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# ifdef USE_AS_STRNCMP
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/* Return 0 if the mismatched index (%rdx + 3 * VEC_SIZE) is
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after the maximum offset (%r11). */
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addq $(VEC_SIZE * 3), %rdx
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cmpq %r11, %rdx
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jae L(zero)
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# ifdef USE_AS_WCSCMP
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xorl %eax, %eax
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movl (%rdi, %rdx), %ecx
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cmpl (%rsi, %rdx), %ecx
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jne L(wcscmp_return)
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# else
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movzbl (%rdi, %rdx), %eax
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movzbl (%rsi, %rdx), %edx
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subl %edx, %eax
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# endif
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# else
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# ifdef USE_AS_WCSCMP
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xorl %eax, %eax
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movl (VEC_SIZE * 3)(%rdi, %rdx), %ecx
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cmpl (VEC_SIZE * 3)(%rsi, %rdx), %ecx
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jne L(wcscmp_return)
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# else
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movzbl (VEC_SIZE * 3)(%rdi, %rdx), %eax
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movzbl (VEC_SIZE * 3)(%rsi, %rdx), %edx
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subl %edx, %eax
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# endif
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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(next_3_vectors):
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vmovdqu VEC_SIZE(%rdi), %ymm6
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VPCMPEQ VEC_SIZE(%rsi), %ymm6, %ymm3
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VPMINU %ymm6, %ymm3, %ymm3
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VPCMPEQ %ymm7, %ymm3, %ymm3
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vpmovmskb %ymm3, %ecx
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testl %ecx, %ecx
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jne L(return_vec_size)
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vmovdqu (VEC_SIZE * 2)(%rdi), %ymm5
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vmovdqu (VEC_SIZE * 3)(%rdi), %ymm4
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vmovdqu (VEC_SIZE * 3)(%rsi), %ymm0
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VPCMPEQ (VEC_SIZE * 2)(%rsi), %ymm5, %ymm2
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VPMINU %ymm5, %ymm2, %ymm2
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VPCMPEQ %ymm4, %ymm0, %ymm0
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VPCMPEQ %ymm7, %ymm2, %ymm2
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vpmovmskb %ymm2, %ecx
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testl %ecx, %ecx
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jne L(return_2_vec_size)
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VPMINU %ymm4, %ymm0, %ymm0
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VPCMPEQ %ymm7, %ymm0, %ymm0
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vpmovmskb %ymm0, %ecx
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testl %ecx, %ecx
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jne L(return_3_vec_size)
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L(main_loop_header):
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leaq (VEC_SIZE * 4)(%rdi), %rdx
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movl $PAGE_SIZE, %ecx
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/* Align load via RAX. */
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andq $-(VEC_SIZE * 4), %rdx
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subq %rdi, %rdx
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leaq (%rdi, %rdx), %rax
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# ifdef USE_AS_STRNCMP
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/* Starting from this point, the maximum offset, or simply the
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'offset', DECREASES by the same amount when base pointers are
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moved forward. Return 0 when:
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1) On match: offset <= the matched vector index.
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2) On mistmach, offset is before the mistmatched index.
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*/
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subq %rdx, %r11
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jbe L(zero)
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# endif
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addq %rsi, %rdx
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movq %rdx, %rsi
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andl $(PAGE_SIZE - 1), %esi
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/* Number of bytes before page crossing. */
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subq %rsi, %rcx
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/* Number of VEC_SIZE * 4 blocks before page crossing. */
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shrq $DIVIDE_BY_VEC_4_SHIFT, %rcx
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/* ESI: Number of VEC_SIZE * 4 blocks before page crossing. */
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movl %ecx, %esi
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jmp L(loop_start)
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.p2align 4
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L(loop):
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# ifdef USE_AS_STRNCMP
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/* Base pointers are moved forward by 4 * VEC_SIZE. Decrease
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the maximum offset (%r11) by the same amount. */
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subq $(VEC_SIZE * 4), %r11
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jbe L(zero)
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# endif
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addq $(VEC_SIZE * 4), %rax
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addq $(VEC_SIZE * 4), %rdx
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L(loop_start):
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testl %esi, %esi
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leal -1(%esi), %esi
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je L(loop_cross_page)
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L(back_to_loop):
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/* Main loop, comparing 4 vectors are a time. */
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vmovdqa (%rax), %ymm0
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vmovdqa VEC_SIZE(%rax), %ymm3
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VPCMPEQ (%rdx), %ymm0, %ymm4
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VPCMPEQ VEC_SIZE(%rdx), %ymm3, %ymm1
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VPMINU %ymm0, %ymm4, %ymm4
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VPMINU %ymm3, %ymm1, %ymm1
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vmovdqa (VEC_SIZE * 2)(%rax), %ymm2
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VPMINU %ymm1, %ymm4, %ymm0
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vmovdqa (VEC_SIZE * 3)(%rax), %ymm3
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VPCMPEQ (VEC_SIZE * 2)(%rdx), %ymm2, %ymm5
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VPCMPEQ (VEC_SIZE * 3)(%rdx), %ymm3, %ymm6
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VPMINU %ymm2, %ymm5, %ymm5
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VPMINU %ymm3, %ymm6, %ymm6
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VPMINU %ymm5, %ymm0, %ymm0
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VPMINU %ymm6, %ymm0, %ymm0
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VPCMPEQ %ymm7, %ymm0, %ymm0
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/* Test each mask (32 bits) individually because for VEC_SIZE
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== 32 is not possible to OR the four masks and keep all bits
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in a 64-bit integer register, differing from SSE2 strcmp
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where ORing is possible. */
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vpmovmskb %ymm0, %ecx
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testl %ecx, %ecx
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je L(loop)
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VPCMPEQ %ymm7, %ymm4, %ymm0
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vpmovmskb %ymm0, %edi
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testl %edi, %edi
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je L(test_vec)
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tzcntl %edi, %ecx
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# ifdef USE_AS_STRNCMP
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cmpq %rcx, %r11
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jbe L(zero)
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# ifdef USE_AS_WCSCMP
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movq %rax, %rsi
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xorl %eax, %eax
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movl (%rsi, %rcx), %edi
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cmpl (%rdx, %rcx), %edi
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jne L(wcscmp_return)
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# else
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movzbl (%rax, %rcx), %eax
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movzbl (%rdx, %rcx), %edx
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subl %edx, %eax
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# endif
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# else
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# ifdef USE_AS_WCSCMP
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movq %rax, %rsi
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xorl %eax, %eax
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movl (%rsi, %rcx), %edi
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cmpl (%rdx, %rcx), %edi
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jne L(wcscmp_return)
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# else
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movzbl (%rax, %rcx), %eax
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movzbl (%rdx, %rcx), %edx
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subl %edx, %eax
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# endif
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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(test_vec):
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# ifdef USE_AS_STRNCMP
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/* The first vector matched. Return 0 if the maximum offset
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(%r11) <= VEC_SIZE. */
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cmpq $VEC_SIZE, %r11
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jbe L(zero)
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# endif
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VPCMPEQ %ymm7, %ymm1, %ymm1
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vpmovmskb %ymm1, %ecx
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testl %ecx, %ecx
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je L(test_2_vec)
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tzcntl %ecx, %edi
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# ifdef USE_AS_STRNCMP
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addq $VEC_SIZE, %rdi
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cmpq %rdi, %r11
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jbe L(zero)
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# ifdef USE_AS_WCSCMP
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movq %rax, %rsi
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xorl %eax, %eax
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movl (%rsi, %rdi), %ecx
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cmpl (%rdx, %rdi), %ecx
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jne L(wcscmp_return)
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# else
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movzbl (%rax, %rdi), %eax
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movzbl (%rdx, %rdi), %edx
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subl %edx, %eax
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# endif
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# else
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# ifdef USE_AS_WCSCMP
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movq %rax, %rsi
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xorl %eax, %eax
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movl VEC_SIZE(%rsi, %rdi), %ecx
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cmpl VEC_SIZE(%rdx, %rdi), %ecx
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jne L(wcscmp_return)
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# else
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movzbl VEC_SIZE(%rax, %rdi), %eax
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movzbl VEC_SIZE(%rdx, %rdi), %edx
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subl %edx, %eax
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# endif
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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(test_2_vec):
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# ifdef USE_AS_STRNCMP
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/* The first 2 vectors matched. Return 0 if the maximum offset
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(%r11) <= 2 * VEC_SIZE. */
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cmpq $(VEC_SIZE * 2), %r11
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jbe L(zero)
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# endif
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VPCMPEQ %ymm7, %ymm5, %ymm5
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vpmovmskb %ymm5, %ecx
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testl %ecx, %ecx
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je L(test_3_vec)
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tzcntl %ecx, %edi
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# ifdef USE_AS_STRNCMP
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addq $(VEC_SIZE * 2), %rdi
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cmpq %rdi, %r11
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jbe L(zero)
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# ifdef USE_AS_WCSCMP
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movq %rax, %rsi
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xorl %eax, %eax
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movl (%rsi, %rdi), %ecx
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cmpl (%rdx, %rdi), %ecx
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jne L(wcscmp_return)
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# else
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movzbl (%rax, %rdi), %eax
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movzbl (%rdx, %rdi), %edx
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subl %edx, %eax
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# endif
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# else
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# ifdef USE_AS_WCSCMP
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movq %rax, %rsi
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xorl %eax, %eax
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movl (VEC_SIZE * 2)(%rsi, %rdi), %ecx
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cmpl (VEC_SIZE * 2)(%rdx, %rdi), %ecx
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jne L(wcscmp_return)
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# else
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movzbl (VEC_SIZE * 2)(%rax, %rdi), %eax
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movzbl (VEC_SIZE * 2)(%rdx, %rdi), %edx
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subl %edx, %eax
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# endif
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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(test_3_vec):
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# ifdef USE_AS_STRNCMP
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/* The first 3 vectors matched. Return 0 if the maximum offset
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(%r11) <= 3 * VEC_SIZE. */
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cmpq $(VEC_SIZE * 3), %r11
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jbe L(zero)
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# endif
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VPCMPEQ %ymm7, %ymm6, %ymm6
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vpmovmskb %ymm6, %esi
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tzcntl %esi, %ecx
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# ifdef USE_AS_STRNCMP
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addq $(VEC_SIZE * 3), %rcx
|
|
cmpq %rcx, %r11
|
|
jbe L(zero)
|
|
# ifdef USE_AS_WCSCMP
|
|
movq %rax, %rsi
|
|
xorl %eax, %eax
|
|
movl (%rsi, %rcx), %esi
|
|
cmpl (%rdx, %rcx), %esi
|
|
jne L(wcscmp_return)
|
|
# else
|
|
movzbl (%rax, %rcx), %eax
|
|
movzbl (%rdx, %rcx), %edx
|
|
subl %edx, %eax
|
|
# endif
|
|
# else
|
|
# ifdef USE_AS_WCSCMP
|
|
movq %rax, %rsi
|
|
xorl %eax, %eax
|
|
movl (VEC_SIZE * 3)(%rsi, %rcx), %esi
|
|
cmpl (VEC_SIZE * 3)(%rdx, %rcx), %esi
|
|
jne L(wcscmp_return)
|
|
# else
|
|
movzbl (VEC_SIZE * 3)(%rax, %rcx), %eax
|
|
movzbl (VEC_SIZE * 3)(%rdx, %rcx), %edx
|
|
subl %edx, %eax
|
|
# endif
|
|
# endif
|
|
VZEROUPPER
|
|
ret
|
|
|
|
.p2align 4
|
|
L(loop_cross_page):
|
|
xorl %r10d, %r10d
|
|
movq %rdx, %rcx
|
|
/* Align load via RDX. We load the extra ECX bytes which should
|
|
be ignored. */
|
|
andl $((VEC_SIZE * 4) - 1), %ecx
|
|
/* R10 is -RCX. */
|
|
subq %rcx, %r10
|
|
|
|
/* This works only if VEC_SIZE * 2 == 64. */
|
|
# if (VEC_SIZE * 2) != 64
|
|
# error (VEC_SIZE * 2) != 64
|
|
# endif
|
|
|
|
/* Check if the first VEC_SIZE * 2 bytes should be ignored. */
|
|
cmpl $(VEC_SIZE * 2), %ecx
|
|
jge L(loop_cross_page_2_vec)
|
|
|
|
vmovdqu (%rax, %r10), %ymm2
|
|
vmovdqu VEC_SIZE(%rax, %r10), %ymm3
|
|
VPCMPEQ (%rdx, %r10), %ymm2, %ymm0
|
|
VPCMPEQ VEC_SIZE(%rdx, %r10), %ymm3, %ymm1
|
|
VPMINU %ymm2, %ymm0, %ymm0
|
|
VPMINU %ymm3, %ymm1, %ymm1
|
|
VPCMPEQ %ymm7, %ymm0, %ymm0
|
|
VPCMPEQ %ymm7, %ymm1, %ymm1
|
|
|
|
vpmovmskb %ymm0, %edi
|
|
vpmovmskb %ymm1, %esi
|
|
|
|
salq $32, %rsi
|
|
xorq %rsi, %rdi
|
|
|
|
/* Since ECX < VEC_SIZE * 2, simply skip the first ECX bytes. */
|
|
shrq %cl, %rdi
|
|
|
|
testq %rdi, %rdi
|
|
je L(loop_cross_page_2_vec)
|
|
tzcntq %rdi, %rcx
|
|
# ifdef USE_AS_STRNCMP
|
|
cmpq %rcx, %r11
|
|
jbe L(zero)
|
|
# ifdef USE_AS_WCSCMP
|
|
movq %rax, %rsi
|
|
xorl %eax, %eax
|
|
movl (%rsi, %rcx), %edi
|
|
cmpl (%rdx, %rcx), %edi
|
|
jne L(wcscmp_return)
|
|
# else
|
|
movzbl (%rax, %rcx), %eax
|
|
movzbl (%rdx, %rcx), %edx
|
|
subl %edx, %eax
|
|
# endif
|
|
# else
|
|
# ifdef USE_AS_WCSCMP
|
|
movq %rax, %rsi
|
|
xorl %eax, %eax
|
|
movl (%rsi, %rcx), %edi
|
|
cmpl (%rdx, %rcx), %edi
|
|
jne L(wcscmp_return)
|
|
# else
|
|
movzbl (%rax, %rcx), %eax
|
|
movzbl (%rdx, %rcx), %edx
|
|
subl %edx, %eax
|
|
# endif
|
|
# endif
|
|
VZEROUPPER
|
|
ret
|
|
|
|
.p2align 4
|
|
L(loop_cross_page_2_vec):
|
|
/* The first VEC_SIZE * 2 bytes match or are ignored. */
|
|
vmovdqu (VEC_SIZE * 2)(%rax, %r10), %ymm2
|
|
vmovdqu (VEC_SIZE * 3)(%rax, %r10), %ymm3
|
|
VPCMPEQ (VEC_SIZE * 2)(%rdx, %r10), %ymm2, %ymm5
|
|
VPMINU %ymm2, %ymm5, %ymm5
|
|
VPCMPEQ (VEC_SIZE * 3)(%rdx, %r10), %ymm3, %ymm6
|
|
VPCMPEQ %ymm7, %ymm5, %ymm5
|
|
VPMINU %ymm3, %ymm6, %ymm6
|
|
VPCMPEQ %ymm7, %ymm6, %ymm6
|
|
|
|
vpmovmskb %ymm5, %edi
|
|
vpmovmskb %ymm6, %esi
|
|
|
|
salq $32, %rsi
|
|
xorq %rsi, %rdi
|
|
|
|
xorl %r8d, %r8d
|
|
/* If ECX > VEC_SIZE * 2, skip ECX - (VEC_SIZE * 2) bytes. */
|
|
subl $(VEC_SIZE * 2), %ecx
|
|
jle 1f
|
|
/* Skip ECX bytes. */
|
|
shrq %cl, %rdi
|
|
/* R8 has number of bytes skipped. */
|
|
movl %ecx, %r8d
|
|
1:
|
|
/* Before jumping back to the loop, set ESI to the number of
|
|
VEC_SIZE * 4 blocks before page crossing. */
|
|
movl $(PAGE_SIZE / (VEC_SIZE * 4) - 1), %esi
|
|
|
|
testq %rdi, %rdi
|
|
# ifdef USE_AS_STRNCMP
|
|
/* At this point, if %rdi value is 0, it already tested
|
|
VEC_SIZE*4+%r10 byte starting from %rax. This label
|
|
checks whether strncmp maximum offset reached or not. */
|
|
je L(string_nbyte_offset_check)
|
|
# else
|
|
je L(back_to_loop)
|
|
# endif
|
|
tzcntq %rdi, %rcx
|
|
addq %r10, %rcx
|
|
/* Adjust for number of bytes skipped. */
|
|
addq %r8, %rcx
|
|
# ifdef USE_AS_STRNCMP
|
|
addq $(VEC_SIZE * 2), %rcx
|
|
subq %rcx, %r11
|
|
jbe L(zero)
|
|
# ifdef USE_AS_WCSCMP
|
|
movq %rax, %rsi
|
|
xorl %eax, %eax
|
|
movl (%rsi, %rcx), %edi
|
|
cmpl (%rdx, %rcx), %edi
|
|
jne L(wcscmp_return)
|
|
# else
|
|
movzbl (%rax, %rcx), %eax
|
|
movzbl (%rdx, %rcx), %edx
|
|
subl %edx, %eax
|
|
# endif
|
|
# else
|
|
# ifdef USE_AS_WCSCMP
|
|
movq %rax, %rsi
|
|
xorl %eax, %eax
|
|
movl (VEC_SIZE * 2)(%rsi, %rcx), %edi
|
|
cmpl (VEC_SIZE * 2)(%rdx, %rcx), %edi
|
|
jne L(wcscmp_return)
|
|
# else
|
|
movzbl (VEC_SIZE * 2)(%rax, %rcx), %eax
|
|
movzbl (VEC_SIZE * 2)(%rdx, %rcx), %edx
|
|
subl %edx, %eax
|
|
# endif
|
|
# endif
|
|
VZEROUPPER
|
|
ret
|
|
|
|
# ifdef USE_AS_STRNCMP
|
|
L(string_nbyte_offset_check):
|
|
leaq (VEC_SIZE * 4)(%r10), %r10
|
|
cmpq %r10, %r11
|
|
jbe L(zero)
|
|
jmp L(back_to_loop)
|
|
# endif
|
|
|
|
.p2align 4
|
|
L(cross_page_loop):
|
|
/* Check one byte/dword at a time. */
|
|
# ifdef USE_AS_WCSCMP
|
|
cmpl %ecx, %eax
|
|
# else
|
|
subl %ecx, %eax
|
|
# endif
|
|
jne L(different)
|
|
addl $SIZE_OF_CHAR, %edx
|
|
cmpl $(VEC_SIZE * 4), %edx
|
|
je L(main_loop_header)
|
|
# ifdef USE_AS_STRNCMP
|
|
cmpq %r11, %rdx
|
|
jae L(zero)
|
|
# endif
|
|
# ifdef USE_AS_WCSCMP
|
|
movl (%rdi, %rdx), %eax
|
|
movl (%rsi, %rdx), %ecx
|
|
# else
|
|
movzbl (%rdi, %rdx), %eax
|
|
movzbl (%rsi, %rdx), %ecx
|
|
# endif
|
|
/* Check null char. */
|
|
testl %eax, %eax
|
|
jne L(cross_page_loop)
|
|
/* Since %eax == 0, subtract is OK for both SIGNED and UNSIGNED
|
|
comparisons. */
|
|
subl %ecx, %eax
|
|
# ifndef USE_AS_WCSCMP
|
|
L(different):
|
|
# endif
|
|
VZEROUPPER
|
|
ret
|
|
|
|
# ifdef USE_AS_WCSCMP
|
|
.p2align 4
|
|
L(different):
|
|
/* Use movl to avoid modifying EFLAGS. */
|
|
movl $0, %eax
|
|
setl %al
|
|
negl %eax
|
|
orl $1, %eax
|
|
VZEROUPPER
|
|
ret
|
|
# endif
|
|
|
|
# ifdef USE_AS_STRNCMP
|
|
.p2align 4
|
|
L(zero):
|
|
xorl %eax, %eax
|
|
VZEROUPPER
|
|
ret
|
|
|
|
.p2align 4
|
|
L(char0):
|
|
# ifdef USE_AS_WCSCMP
|
|
xorl %eax, %eax
|
|
movl (%rdi), %ecx
|
|
cmpl (%rsi), %ecx
|
|
jne L(wcscmp_return)
|
|
# else
|
|
movzbl (%rsi), %ecx
|
|
movzbl (%rdi), %eax
|
|
subl %ecx, %eax
|
|
# endif
|
|
VZEROUPPER
|
|
ret
|
|
# endif
|
|
|
|
.p2align 4
|
|
L(last_vector):
|
|
addq %rdx, %rdi
|
|
addq %rdx, %rsi
|
|
# ifdef USE_AS_STRNCMP
|
|
subq %rdx, %r11
|
|
# endif
|
|
tzcntl %ecx, %edx
|
|
# ifdef USE_AS_STRNCMP
|
|
cmpq %r11, %rdx
|
|
jae L(zero)
|
|
# endif
|
|
# ifdef USE_AS_WCSCMP
|
|
xorl %eax, %eax
|
|
movl (%rdi, %rdx), %ecx
|
|
cmpl (%rsi, %rdx), %ecx
|
|
jne L(wcscmp_return)
|
|
# else
|
|
movzbl (%rdi, %rdx), %eax
|
|
movzbl (%rsi, %rdx), %edx
|
|
subl %edx, %eax
|
|
# endif
|
|
VZEROUPPER
|
|
ret
|
|
|
|
/* Comparing on page boundary region requires special treatment:
|
|
It must done one vector at the time, starting with the wider
|
|
ymm vector if possible, if not, with xmm. If fetching 16 bytes
|
|
(xmm) still passes the boundary, byte comparison must be done.
|
|
*/
|
|
.p2align 4
|
|
L(cross_page):
|
|
/* Try one ymm vector at a time. */
|
|
cmpl $(PAGE_SIZE - VEC_SIZE), %eax
|
|
jg L(cross_page_1_vector)
|
|
L(loop_1_vector):
|
|
vmovdqu (%rdi, %rdx), %ymm1
|
|
VPCMPEQ (%rsi, %rdx), %ymm1, %ymm0
|
|
VPMINU %ymm1, %ymm0, %ymm0
|
|
VPCMPEQ %ymm7, %ymm0, %ymm0
|
|
vpmovmskb %ymm0, %ecx
|
|
testl %ecx, %ecx
|
|
jne L(last_vector)
|
|
|
|
addl $VEC_SIZE, %edx
|
|
|
|
addl $VEC_SIZE, %eax
|
|
# ifdef USE_AS_STRNCMP
|
|
/* Return 0 if the current offset (%rdx) >= the maximum offset
|
|
(%r11). */
|
|
cmpq %r11, %rdx
|
|
jae L(zero)
|
|
# endif
|
|
cmpl $(PAGE_SIZE - VEC_SIZE), %eax
|
|
jle L(loop_1_vector)
|
|
L(cross_page_1_vector):
|
|
/* Less than 32 bytes to check, try one xmm vector. */
|
|
cmpl $(PAGE_SIZE - 16), %eax
|
|
jg L(cross_page_1_xmm)
|
|
vmovdqu (%rdi, %rdx), %xmm1
|
|
VPCMPEQ (%rsi, %rdx), %xmm1, %xmm0
|
|
VPMINU %xmm1, %xmm0, %xmm0
|
|
VPCMPEQ %xmm7, %xmm0, %xmm0
|
|
vpmovmskb %xmm0, %ecx
|
|
testl %ecx, %ecx
|
|
jne L(last_vector)
|
|
|
|
addl $16, %edx
|
|
# ifndef USE_AS_WCSCMP
|
|
addl $16, %eax
|
|
# endif
|
|
# ifdef USE_AS_STRNCMP
|
|
/* Return 0 if the current offset (%rdx) >= the maximum offset
|
|
(%r11). */
|
|
cmpq %r11, %rdx
|
|
jae L(zero)
|
|
# endif
|
|
|
|
L(cross_page_1_xmm):
|
|
# ifndef USE_AS_WCSCMP
|
|
/* Less than 16 bytes to check, try 8 byte vector. NB: No need
|
|
for wcscmp nor wcsncmp since wide char is 4 bytes. */
|
|
cmpl $(PAGE_SIZE - 8), %eax
|
|
jg L(cross_page_8bytes)
|
|
vmovq (%rdi, %rdx), %xmm1
|
|
vmovq (%rsi, %rdx), %xmm0
|
|
VPCMPEQ %xmm0, %xmm1, %xmm0
|
|
VPMINU %xmm1, %xmm0, %xmm0
|
|
VPCMPEQ %xmm7, %xmm0, %xmm0
|
|
vpmovmskb %xmm0, %ecx
|
|
/* Only last 8 bits are valid. */
|
|
andl $0xff, %ecx
|
|
testl %ecx, %ecx
|
|
jne L(last_vector)
|
|
|
|
addl $8, %edx
|
|
addl $8, %eax
|
|
# ifdef USE_AS_STRNCMP
|
|
/* Return 0 if the current offset (%rdx) >= the maximum offset
|
|
(%r11). */
|
|
cmpq %r11, %rdx
|
|
jae L(zero)
|
|
# endif
|
|
|
|
L(cross_page_8bytes):
|
|
/* Less than 8 bytes to check, try 4 byte vector. */
|
|
cmpl $(PAGE_SIZE - 4), %eax
|
|
jg L(cross_page_4bytes)
|
|
vmovd (%rdi, %rdx), %xmm1
|
|
vmovd (%rsi, %rdx), %xmm0
|
|
VPCMPEQ %xmm0, %xmm1, %xmm0
|
|
VPMINU %xmm1, %xmm0, %xmm0
|
|
VPCMPEQ %xmm7, %xmm0, %xmm0
|
|
vpmovmskb %xmm0, %ecx
|
|
/* Only last 4 bits are valid. */
|
|
andl $0xf, %ecx
|
|
testl %ecx, %ecx
|
|
jne L(last_vector)
|
|
|
|
addl $4, %edx
|
|
# ifdef USE_AS_STRNCMP
|
|
/* Return 0 if the current offset (%rdx) >= the maximum offset
|
|
(%r11). */
|
|
cmpq %r11, %rdx
|
|
jae L(zero)
|
|
# endif
|
|
|
|
L(cross_page_4bytes):
|
|
# endif
|
|
/* Less than 4 bytes to check, try one byte/dword at a time. */
|
|
# ifdef USE_AS_STRNCMP
|
|
cmpq %r11, %rdx
|
|
jae L(zero)
|
|
# endif
|
|
# ifdef USE_AS_WCSCMP
|
|
movl (%rdi, %rdx), %eax
|
|
movl (%rsi, %rdx), %ecx
|
|
# else
|
|
movzbl (%rdi, %rdx), %eax
|
|
movzbl (%rsi, %rdx), %ecx
|
|
# endif
|
|
testl %eax, %eax
|
|
jne L(cross_page_loop)
|
|
subl %ecx, %eax
|
|
VZEROUPPER
|
|
ret
|
|
END (STRCMP)
|
|
#endif
|