diff options
Diffstat (limited to 'sysdeps/x86_64/multiarch/memcmp-avx2-movbe.S')
| -rw-r--r-- | sysdeps/x86_64/multiarch/memcmp-avx2-movbe.S | 425 |
1 files changed, 425 insertions, 0 deletions
diff --git a/sysdeps/x86_64/multiarch/memcmp-avx2-movbe.S b/sysdeps/x86_64/multiarch/memcmp-avx2-movbe.S new file mode 100644 index 0000000000..47630dd97b --- /dev/null +++ b/sysdeps/x86_64/multiarch/memcmp-avx2-movbe.S @@ -0,0 +1,425 @@ +/* memcmp/wmemcmp optimized with AVX2. + Copyright (C) 2017 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <http://www.gnu.org/licenses/>. */ + +#if IS_IN (libc) + +/* memcmp/wmemcmp is implemented as: + 1. For size from 2 to 7 bytes, load as big endian with movbe and bswap + to avoid branches. + 2. Use overlapping compare to avoid branch. + 3. Use vector compare when size >= 4 bytes for memcmp or size >= 8 + bytes for wmemcmp. + 4. If size is 8 * VEC_SIZE or less, unroll the loop. + 5. Compare 4 * VEC_SIZE at a time with the aligned first memory + area. + 6. Use 2 vector compares when size is 2 * VEC_SIZE or less. + 7. Use 4 vector compares when size is 4 * VEC_SIZE or less. + 8. Use 8 vector compares when size is 8 * VEC_SIZE or less. */ + +# include <sysdep.h> + +# ifndef MEMCMP +# define MEMCMP __memcmp_avx2_movbe +# endif + +# ifdef USE_AS_WMEMCMP +# define VPCMPEQ vpcmpeqd +# else +# define VPCMPEQ vpcmpeqb +# endif + +# ifndef VZEROUPPER +# define VZEROUPPER vzeroupper +# endif + +# define VEC_SIZE 32 +# define VEC_MASK ((1 << VEC_SIZE) - 1) + +/* Warning! + wmemcmp has to use SIGNED comparison for elements. + memcmp has to use UNSIGNED comparison for elemnts. +*/ + + .section .text.avx,"ax",@progbits +ENTRY (MEMCMP) +# ifdef USE_AS_WMEMCMP + shl $2, %rdx +# endif + cmpq $VEC_SIZE, %rdx + jb L(less_vec) + cmpq $(VEC_SIZE * 2), %rdx + ja L(more_2x_vec) + +L(last_2x_vec): + /* From VEC to 2 * VEC. No branch when size == VEC_SIZE. */ + vmovdqu (%rsi), %ymm2 + VPCMPEQ (%rdi), %ymm2, %ymm2 + vpmovmskb %ymm2, %eax + subl $VEC_MASK, %eax + jnz L(first_vec) + +L(last_vec): + /* Use overlapping loads to avoid branches. */ + leaq -VEC_SIZE(%rdi, %rdx), %rdi + leaq -VEC_SIZE(%rsi, %rdx), %rsi + vmovdqu (%rsi), %ymm2 + VPCMPEQ (%rdi), %ymm2, %ymm2 + vpmovmskb %ymm2, %eax + subl $VEC_MASK, %eax + jnz L(first_vec) + VZEROUPPER + ret + + .p2align 4 +L(first_vec): + /* A byte or int32 is different within 16 or 32 bytes. */ + tzcntl %eax, %ecx +# ifdef USE_AS_WMEMCMP + xorl %eax, %eax + movl (%rdi, %rcx), %edx + cmpl (%rsi, %rcx), %edx +L(wmemcmp_return): + setl %al + negl %eax + orl $1, %eax +# else + movzbl (%rdi, %rcx), %eax + movzbl (%rsi, %rcx), %edx + sub %edx, %eax +# endif + VZEROUPPER + ret + +# ifdef USE_AS_WMEMCMP + .p2align 4 +L(4): + xorl %eax, %eax + movl (%rdi), %edx + cmpl (%rsi), %edx + jne L(wmemcmp_return) + ret +# else + .p2align 4 +L(between_4_7): + /* Load as big endian with overlapping movbe to avoid branches. */ + movbe (%rdi), %eax + movbe (%rsi), %ecx + shlq $32, %rax + shlq $32, %rcx + movbe -4(%rdi, %rdx), %edi + movbe -4(%rsi, %rdx), %esi + orq %rdi, %rax + orq %rsi, %rcx + subq %rcx, %rax + je L(exit) + sbbl %eax, %eax + orl $1, %eax + ret + + .p2align 4 +L(exit): + ret + + .p2align 4 +L(between_2_3): + /* Load as big endian with overlapping loads and bswap to avoid + branches. */ + movzwl -2(%rdi, %rdx), %eax + movzwl -2(%rsi, %rdx), %ecx + shll $16, %eax + shll $16, %ecx + movzwl (%rdi), %edi + movzwl (%rsi), %esi + orl %edi, %eax + orl %esi, %ecx + bswap %eax + bswap %ecx + subl %ecx, %eax + ret + + .p2align 4 +L(1): + movzbl (%rdi), %eax + movzbl (%rsi), %ecx + subl %ecx, %eax + ret +# endif + + .p2align 4 +L(zero): + xorl %eax, %eax + ret + + .p2align 4 +L(less_vec): +# ifdef USE_AS_WMEMCMP + /* It can only be 0, 4, 8, 12, 16, 20, 24, 28 bytes. */ + cmpb $4, %dl + je L(4) + jb L(zero) +# else + cmpb $1, %dl + je L(1) + jb L(zero) + cmpb $4, %dl + jb L(between_2_3) + cmpb $8, %dl + jb L(between_4_7) +# endif + cmpb $16, %dl + jae L(between_16_31) + /* It is between 8 and 15 bytes. */ + vmovq (%rdi), %xmm1 + vmovq (%rsi), %xmm2 + VPCMPEQ %xmm1, %xmm2, %xmm2 + vpmovmskb %xmm2, %eax + subl $0xffff, %eax + jnz L(first_vec) + /* Use overlapping loads to avoid branches. */ + leaq -8(%rdi, %rdx), %rdi + leaq -8(%rsi, %rdx), %rsi + vmovq (%rdi), %xmm1 + vmovq (%rsi), %xmm2 + VPCMPEQ %xmm1, %xmm2, %xmm2 + vpmovmskb %xmm2, %eax + subl $0xffff, %eax + jnz L(first_vec) + ret + + .p2align 4 +L(between_16_31): + /* From 16 to 31 bytes. No branch when size == 16. */ + vmovdqu (%rsi), %xmm2 + VPCMPEQ (%rdi), %xmm2, %xmm2 + vpmovmskb %xmm2, %eax + subl $0xffff, %eax + jnz L(first_vec) + + /* Use overlapping loads to avoid branches. */ + leaq -16(%rdi, %rdx), %rdi + leaq -16(%rsi, %rdx), %rsi + vmovdqu (%rsi), %xmm2 + VPCMPEQ (%rdi), %xmm2, %xmm2 + vpmovmskb %xmm2, %eax + subl $0xffff, %eax + jnz L(first_vec) + ret + + .p2align 4 +L(more_2x_vec): + /* More than 2 * VEC. */ + cmpq $(VEC_SIZE * 8), %rdx + ja L(more_8x_vec) + cmpq $(VEC_SIZE * 4), %rdx + jb L(last_4x_vec) + + /* From 4 * VEC to 8 * VEC, inclusively. */ + vmovdqu (%rsi), %ymm1 + VPCMPEQ (%rdi), %ymm1, %ymm1 + + vmovdqu VEC_SIZE(%rsi), %ymm2 + VPCMPEQ VEC_SIZE(%rdi), %ymm2, %ymm2 + + vmovdqu (VEC_SIZE * 2)(%rsi), %ymm3 + VPCMPEQ (VEC_SIZE * 2)(%rdi), %ymm3, %ymm3 + + vmovdqu (VEC_SIZE * 3)(%rsi), %ymm4 + VPCMPEQ (VEC_SIZE * 3)(%rdi), %ymm4, %ymm4 + + vpand %ymm1, %ymm2, %ymm5 + vpand %ymm3, %ymm4, %ymm6 + vpand %ymm5, %ymm6, %ymm5 + + vpmovmskb %ymm5, %eax + subl $VEC_MASK, %eax + jnz L(4x_vec_end) + + leaq -(4 * VEC_SIZE)(%rdi, %rdx), %rdi + leaq -(4 * VEC_SIZE)(%rsi, %rdx), %rsi + vmovdqu (%rsi), %ymm1 + VPCMPEQ (%rdi), %ymm1, %ymm1 + + vmovdqu VEC_SIZE(%rsi), %ymm2 + VPCMPEQ VEC_SIZE(%rdi), %ymm2, %ymm2 + vpand %ymm2, %ymm1, %ymm5 + + vmovdqu (VEC_SIZE * 2)(%rsi), %ymm3 + VPCMPEQ (VEC_SIZE * 2)(%rdi), %ymm3, %ymm3 + vpand %ymm3, %ymm5, %ymm5 + + vmovdqu (VEC_SIZE * 3)(%rsi), %ymm4 + VPCMPEQ (VEC_SIZE * 3)(%rdi), %ymm4, %ymm4 + vpand %ymm4, %ymm5, %ymm5 + + vpmovmskb %ymm5, %eax + subl $VEC_MASK, %eax + jnz L(4x_vec_end) + VZEROUPPER + ret + + .p2align 4 +L(more_8x_vec): + /* More than 8 * VEC. Check the first VEC. */ + vmovdqu (%rsi), %ymm2 + VPCMPEQ (%rdi), %ymm2, %ymm2 + vpmovmskb %ymm2, %eax + subl $VEC_MASK, %eax + jnz L(first_vec) + + /* Align the first memory area for aligned loads in the loop. + Compute how much the first memory area is misaligned. */ + movq %rdi, %rcx + andl $(VEC_SIZE - 1), %ecx + /* Get the negative of offset for alignment. */ + subq $VEC_SIZE, %rcx + /* Adjust the second memory area. */ + subq %rcx, %rsi + /* Adjust the first memory area which should be aligned now. */ + subq %rcx, %rdi + /* Adjust length. */ + addq %rcx, %rdx + +L(loop_4x_vec): + /* Compare 4 * VEC at a time forward. */ + vmovdqu (%rsi), %ymm1 + VPCMPEQ (%rdi), %ymm1, %ymm1 + + vmovdqu VEC_SIZE(%rsi), %ymm2 + VPCMPEQ VEC_SIZE(%rdi), %ymm2, %ymm2 + vpand %ymm2, %ymm1, %ymm5 + + vmovdqu (VEC_SIZE * 2)(%rsi), %ymm3 + VPCMPEQ (VEC_SIZE * 2)(%rdi), %ymm3, %ymm3 + vpand %ymm3, %ymm5, %ymm5 + + vmovdqu (VEC_SIZE * 3)(%rsi), %ymm4 + VPCMPEQ (VEC_SIZE * 3)(%rdi), %ymm4, %ymm4 + vpand %ymm4, %ymm5, %ymm5 + + vpmovmskb %ymm5, %eax + subl $VEC_MASK, %eax + jnz L(4x_vec_end) + + addq $(VEC_SIZE * 4), %rdi + addq $(VEC_SIZE * 4), %rsi + + subq $(VEC_SIZE * 4), %rdx + cmpq $(VEC_SIZE * 4), %rdx + jae L(loop_4x_vec) + + /* Less than 4 * VEC. */ + cmpq $VEC_SIZE, %rdx + jbe L(last_vec) + cmpq $(VEC_SIZE * 2), %rdx + jbe L(last_2x_vec) + +L(last_4x_vec): + /* From 2 * VEC to 4 * VEC. */ + vmovdqu (%rsi), %ymm2 + VPCMPEQ (%rdi), %ymm2, %ymm2 + vpmovmskb %ymm2, %eax + subl $VEC_MASK, %eax + jnz L(first_vec) + + addq $VEC_SIZE, %rdi + addq $VEC_SIZE, %rsi + vmovdqu (%rsi), %ymm2 + VPCMPEQ (%rdi), %ymm2, %ymm2 + vpmovmskb %ymm2, %eax + subl $VEC_MASK, %eax + jnz L(first_vec) + + /* Use overlapping loads to avoid branches. */ + leaq -(3 * VEC_SIZE)(%rdi, %rdx), %rdi + leaq -(3 * VEC_SIZE)(%rsi, %rdx), %rsi + vmovdqu (%rsi), %ymm2 + VPCMPEQ (%rdi), %ymm2, %ymm2 + vpmovmskb %ymm2, %eax + subl $VEC_MASK, %eax + jnz L(first_vec) + + addq $VEC_SIZE, %rdi + addq $VEC_SIZE, %rsi + vmovdqu (%rsi), %ymm2 + VPCMPEQ (%rdi), %ymm2, %ymm2 + vpmovmskb %ymm2, %eax + subl $VEC_MASK, %eax + jnz L(first_vec) + VZEROUPPER + ret + + .p2align 4 +L(4x_vec_end): + vpmovmskb %ymm1, %eax + subl $VEC_MASK, %eax + jnz L(first_vec) + vpmovmskb %ymm2, %eax + subl $VEC_MASK, %eax + jnz L(first_vec_x1) + vpmovmskb %ymm3, %eax + subl $VEC_MASK, %eax + jnz L(first_vec_x2) + vpmovmskb %ymm4, %eax + subl $VEC_MASK, %eax + tzcntl %eax, %ecx +# ifdef USE_AS_WMEMCMP + xorl %eax, %eax + movl (VEC_SIZE * 3)(%rdi, %rcx), %edx + cmpl (VEC_SIZE * 3)(%rsi, %rcx), %edx + jmp L(wmemcmp_return) +# else + movzbl (VEC_SIZE * 3)(%rdi, %rcx), %eax + movzbl (VEC_SIZE * 3)(%rsi, %rcx), %edx + sub %edx, %eax +# endif + VZEROUPPER + ret + + .p2align 4 +L(first_vec_x1): + tzcntl %eax, %ecx +# ifdef USE_AS_WMEMCMP + xorl %eax, %eax + movl VEC_SIZE(%rdi, %rcx), %edx + cmpl VEC_SIZE(%rsi, %rcx), %edx + jmp L(wmemcmp_return) +# else + movzbl VEC_SIZE(%rdi, %rcx), %eax + movzbl VEC_SIZE(%rsi, %rcx), %edx + sub %edx, %eax +# endif + VZEROUPPER + ret + + .p2align 4 +L(first_vec_x2): + tzcntl %eax, %ecx +# ifdef USE_AS_WMEMCMP + xorl %eax, %eax + movl (VEC_SIZE * 2)(%rdi, %rcx), %edx + cmpl (VEC_SIZE * 2)(%rsi, %rcx), %edx + jmp L(wmemcmp_return) +# else + movzbl (VEC_SIZE * 2)(%rdi, %rcx), %eax + movzbl (VEC_SIZE * 2)(%rsi, %rcx), %edx + sub %edx, %eax +# endif + VZEROUPPER + ret +END (MEMCMP) +#endif |