diff options
Diffstat (limited to 'sysdeps/x86_64/multiarch/strlen-avx2.S')
| -rw-r--r-- | sysdeps/x86_64/multiarch/strlen-avx2.S | 532 |
1 files changed, 322 insertions, 210 deletions
diff --git a/sysdeps/x86_64/multiarch/strlen-avx2.S b/sysdeps/x86_64/multiarch/strlen-avx2.S index 1caae9e6bc..bd2e6ee44a 100644 --- a/sysdeps/x86_64/multiarch/strlen-avx2.S +++ b/sysdeps/x86_64/multiarch/strlen-avx2.S @@ -27,9 +27,11 @@ # ifdef USE_AS_WCSLEN # define VPCMPEQ vpcmpeqd # define VPMINU vpminud +# define CHAR_SIZE 4 # else # define VPCMPEQ vpcmpeqb # define VPMINU vpminub +# define CHAR_SIZE 1 # endif # ifndef VZEROUPPER @@ -41,349 +43,459 @@ # endif # define VEC_SIZE 32 +# define PAGE_SIZE 4096 .section SECTION(.text),"ax",@progbits ENTRY (STRLEN) # ifdef USE_AS_STRNLEN - /* Check for zero length. */ + /* Check zero length. */ test %RSI_LP, %RSI_LP jz L(zero) + /* Store max len in R8_LP before adjusting if using WCSLEN. */ + mov %RSI_LP, %R8_LP # ifdef USE_AS_WCSLEN shl $2, %RSI_LP # elif defined __ILP32__ /* Clear the upper 32 bits. */ movl %esi, %esi # endif - mov %RSI_LP, %R8_LP # endif - movl %edi, %ecx + movl %edi, %eax movq %rdi, %rdx vpxor %xmm0, %xmm0, %xmm0 - + /* Clear high bits from edi. Only keeping bits relevant to page + cross check. */ + andl $(PAGE_SIZE - 1), %eax /* Check if we may cross page boundary with one vector load. */ - andl $(2 * VEC_SIZE - 1), %ecx - cmpl $VEC_SIZE, %ecx - ja L(cros_page_boundary) + cmpl $(PAGE_SIZE - VEC_SIZE), %eax + ja L(cross_page_boundary) /* Check the first VEC_SIZE bytes. */ - VPCMPEQ (%rdi), %ymm0, %ymm1 - vpmovmskb %ymm1, %eax - testl %eax, %eax - + VPCMPEQ (%rdi), %ymm0, %ymm1 + vpmovmskb %ymm1, %eax # ifdef USE_AS_STRNLEN - jnz L(first_vec_x0_check) - /* Adjust length and check the end of data. */ - subq $VEC_SIZE, %rsi - jbe L(max) -# else - jnz L(first_vec_x0) + /* If length < VEC_SIZE handle special. */ + cmpq $VEC_SIZE, %rsi + jbe L(first_vec_x0) # endif - - /* Align data for aligned loads in the loop. */ - addq $VEC_SIZE, %rdi - andl $(VEC_SIZE - 1), %ecx - andq $-VEC_SIZE, %rdi + /* If empty continue to aligned_more. Otherwise return bit + position of first match. */ + testl %eax, %eax + jz L(aligned_more) + tzcntl %eax, %eax +# ifdef USE_AS_WCSLEN + shrl $2, %eax +# endif + VZEROUPPER_RETURN # ifdef USE_AS_STRNLEN - /* Adjust length. */ - addq %rcx, %rsi +L(zero): + xorl %eax, %eax + ret - subq $(VEC_SIZE * 4), %rsi - jbe L(last_4x_vec_or_less) + .p2align 4 +L(first_vec_x0): + /* Set bit for max len so that tzcnt will return min of max len + and position of first match. */ + btsq %rsi, %rax + tzcntl %eax, %eax +# ifdef USE_AS_WCSLEN + shrl $2, %eax +# endif + VZEROUPPER_RETURN # endif - jmp L(more_4x_vec) .p2align 4 -L(cros_page_boundary): - andl $(VEC_SIZE - 1), %ecx - andq $-VEC_SIZE, %rdi - VPCMPEQ (%rdi), %ymm0, %ymm1 - vpmovmskb %ymm1, %eax - /* Remove the leading bytes. */ - sarl %cl, %eax - testl %eax, %eax - jz L(aligned_more) +L(first_vec_x1): tzcntl %eax, %eax + /* Safe to use 32 bit instructions as these are only called for + size = [1, 159]. */ # ifdef USE_AS_STRNLEN - /* Check the end of data. */ - cmpq %rax, %rsi - jbe L(max) + /* Use ecx which was computed earlier to compute correct value. + */ + subl $(VEC_SIZE * 4 + 1), %ecx + addl %ecx, %eax +# else + subl %edx, %edi + incl %edi + addl %edi, %eax # endif - addq %rdi, %rax - addq %rcx, %rax - subq %rdx, %rax # ifdef USE_AS_WCSLEN - shrq $2, %rax + shrl $2, %eax # endif -L(return_vzeroupper): - ZERO_UPPER_VEC_REGISTERS_RETURN + VZEROUPPER_RETURN .p2align 4 -L(aligned_more): +L(first_vec_x2): + tzcntl %eax, %eax + /* Safe to use 32 bit instructions as these are only called for + size = [1, 159]. */ # ifdef USE_AS_STRNLEN - /* "rcx" is less than VEC_SIZE. Calculate "rdx + rcx - VEC_SIZE" - with "rdx - (VEC_SIZE - rcx)" instead of "(rdx + rcx) - VEC_SIZE" - to void possible addition overflow. */ - negq %rcx - addq $VEC_SIZE, %rcx - - /* Check the end of data. */ - subq %rcx, %rsi - jbe L(max) + /* Use ecx which was computed earlier to compute correct value. + */ + subl $(VEC_SIZE * 3 + 1), %ecx + addl %ecx, %eax +# else + subl %edx, %edi + addl $(VEC_SIZE + 1), %edi + addl %edi, %eax # endif +# ifdef USE_AS_WCSLEN + shrl $2, %eax +# endif + VZEROUPPER_RETURN - addq $VEC_SIZE, %rdi + .p2align 4 +L(first_vec_x3): + tzcntl %eax, %eax + /* Safe to use 32 bit instructions as these are only called for + size = [1, 159]. */ +# ifdef USE_AS_STRNLEN + /* Use ecx which was computed earlier to compute correct value. + */ + subl $(VEC_SIZE * 2 + 1), %ecx + addl %ecx, %eax +# else + subl %edx, %edi + addl $(VEC_SIZE * 2 + 1), %edi + addl %edi, %eax +# endif +# ifdef USE_AS_WCSLEN + shrl $2, %eax +# endif + VZEROUPPER_RETURN + .p2align 4 +L(first_vec_x4): + tzcntl %eax, %eax + /* Safe to use 32 bit instructions as these are only called for + size = [1, 159]. */ # ifdef USE_AS_STRNLEN - subq $(VEC_SIZE * 4), %rsi - jbe L(last_4x_vec_or_less) + /* Use ecx which was computed earlier to compute correct value. + */ + subl $(VEC_SIZE + 1), %ecx + addl %ecx, %eax +# else + subl %edx, %edi + addl $(VEC_SIZE * 3 + 1), %edi + addl %edi, %eax # endif +# ifdef USE_AS_WCSLEN + shrl $2, %eax +# endif + VZEROUPPER_RETURN -L(more_4x_vec): + .p2align 5 +L(aligned_more): + /* Align data to VEC_SIZE - 1. This is the same number of + instructions as using andq with -VEC_SIZE but saves 4 bytes of + code on the x4 check. */ + orq $(VEC_SIZE - 1), %rdi +L(cross_page_continue): /* Check the first 4 * VEC_SIZE. Only one VEC_SIZE at a time since data is only aligned to VEC_SIZE. */ - VPCMPEQ (%rdi), %ymm0, %ymm1 - vpmovmskb %ymm1, %eax - testl %eax, %eax - jnz L(first_vec_x0) - - VPCMPEQ VEC_SIZE(%rdi), %ymm0, %ymm1 - vpmovmskb %ymm1, %eax +# ifdef USE_AS_STRNLEN + /* + 1 because rdi is aligned to VEC_SIZE - 1. + CHAR_SIZE because + it simplies the logic in last_4x_vec_or_less. */ + leaq (VEC_SIZE * 4 + CHAR_SIZE + 1)(%rdi), %rcx + subq %rdx, %rcx +# endif + /* Load first VEC regardless. */ + VPCMPEQ 1(%rdi), %ymm0, %ymm1 +# ifdef USE_AS_STRNLEN + /* Adjust length. If near end handle specially. */ + subq %rcx, %rsi + jb L(last_4x_vec_or_less) +# endif + vpmovmskb %ymm1, %eax testl %eax, %eax jnz L(first_vec_x1) - VPCMPEQ (VEC_SIZE * 2)(%rdi), %ymm0, %ymm1 - vpmovmskb %ymm1, %eax + VPCMPEQ (VEC_SIZE + 1)(%rdi), %ymm0, %ymm1 + vpmovmskb %ymm1, %eax testl %eax, %eax jnz L(first_vec_x2) - VPCMPEQ (VEC_SIZE * 3)(%rdi), %ymm0, %ymm1 - vpmovmskb %ymm1, %eax + VPCMPEQ (VEC_SIZE * 2 + 1)(%rdi), %ymm0, %ymm1 + vpmovmskb %ymm1, %eax testl %eax, %eax jnz L(first_vec_x3) - addq $(VEC_SIZE * 4), %rdi - -# ifdef USE_AS_STRNLEN - subq $(VEC_SIZE * 4), %rsi - jbe L(last_4x_vec_or_less) -# endif - - /* Align data to 4 * VEC_SIZE. */ - movq %rdi, %rcx - andl $(4 * VEC_SIZE - 1), %ecx - andq $-(4 * VEC_SIZE), %rdi + VPCMPEQ (VEC_SIZE * 3 + 1)(%rdi), %ymm0, %ymm1 + vpmovmskb %ymm1, %eax + testl %eax, %eax + jnz L(first_vec_x4) + /* Align data to VEC_SIZE * 4 - 1. */ # ifdef USE_AS_STRNLEN - /* Adjust length. */ + /* Before adjusting length check if at last VEC_SIZE * 4. */ + cmpq $(VEC_SIZE * 4 - 1), %rsi + jbe L(last_4x_vec_or_less_load) + incq %rdi + movl %edi, %ecx + orq $(VEC_SIZE * 4 - 1), %rdi + andl $(VEC_SIZE * 4 - 1), %ecx + /* Readjust length. */ addq %rcx, %rsi +# else + incq %rdi + orq $(VEC_SIZE * 4 - 1), %rdi # endif - + /* Compare 4 * VEC at a time forward. */ .p2align 4 L(loop_4x_vec): - /* Compare 4 * VEC at a time forward. */ - vmovdqa (%rdi), %ymm1 - vmovdqa VEC_SIZE(%rdi), %ymm2 - vmovdqa (VEC_SIZE * 2)(%rdi), %ymm3 - vmovdqa (VEC_SIZE * 3)(%rdi), %ymm4 - VPMINU %ymm1, %ymm2, %ymm5 - VPMINU %ymm3, %ymm4, %ymm6 - VPMINU %ymm5, %ymm6, %ymm5 - - VPCMPEQ %ymm5, %ymm0, %ymm5 - vpmovmskb %ymm5, %eax - testl %eax, %eax - jnz L(4x_vec_end) - - addq $(VEC_SIZE * 4), %rdi - -# ifndef USE_AS_STRNLEN - jmp L(loop_4x_vec) -# else +# ifdef USE_AS_STRNLEN + /* Break if at end of length. */ subq $(VEC_SIZE * 4), %rsi - ja L(loop_4x_vec) - -L(last_4x_vec_or_less): - /* Less than 4 * VEC and aligned to VEC_SIZE. */ - addl $(VEC_SIZE * 2), %esi - jle L(last_2x_vec) + jb L(last_4x_vec_or_less_cmpeq) +# endif + /* Save some code size by microfusing VPMINU with the load. Since + the matches in ymm2/ymm4 can only be returned if there where no + matches in ymm1/ymm3 respectively there is no issue with overlap. + */ + vmovdqa 1(%rdi), %ymm1 + VPMINU (VEC_SIZE + 1)(%rdi), %ymm1, %ymm2 + vmovdqa (VEC_SIZE * 2 + 1)(%rdi), %ymm3 + VPMINU (VEC_SIZE * 3 + 1)(%rdi), %ymm3, %ymm4 + + VPMINU %ymm2, %ymm4, %ymm5 + VPCMPEQ %ymm5, %ymm0, %ymm5 + vpmovmskb %ymm5, %ecx - VPCMPEQ (%rdi), %ymm0, %ymm1 - vpmovmskb %ymm1, %eax - testl %eax, %eax - jnz L(first_vec_x0) + subq $-(VEC_SIZE * 4), %rdi + testl %ecx, %ecx + jz L(loop_4x_vec) - VPCMPEQ VEC_SIZE(%rdi), %ymm0, %ymm1 - vpmovmskb %ymm1, %eax - testl %eax, %eax - jnz L(first_vec_x1) - VPCMPEQ (VEC_SIZE * 2)(%rdi), %ymm0, %ymm1 - vpmovmskb %ymm1, %eax + VPCMPEQ %ymm1, %ymm0, %ymm1 + vpmovmskb %ymm1, %eax + subq %rdx, %rdi testl %eax, %eax + jnz L(last_vec_return_x0) - jnz L(first_vec_x2_check) - subl $VEC_SIZE, %esi - jle L(max) - - VPCMPEQ (VEC_SIZE * 3)(%rdi), %ymm0, %ymm1 - vpmovmskb %ymm1, %eax + VPCMPEQ %ymm2, %ymm0, %ymm2 + vpmovmskb %ymm2, %eax testl %eax, %eax - - jnz L(first_vec_x3_check) - movq %r8, %rax -# ifdef USE_AS_WCSLEN + jnz L(last_vec_return_x1) + + /* Combine last 2 VEC. */ + VPCMPEQ %ymm3, %ymm0, %ymm3 + vpmovmskb %ymm3, %eax + /* rcx has combined result from all 4 VEC. It will only be used if + the first 3 other VEC all did not contain a match. */ + salq $32, %rcx + orq %rcx, %rax + tzcntq %rax, %rax + subq $(VEC_SIZE * 2 - 1), %rdi + addq %rdi, %rax +# ifdef USE_AS_WCSLEN shrq $2, %rax -# endif +# endif VZEROUPPER_RETURN + +# ifdef USE_AS_STRNLEN .p2align 4 -L(last_2x_vec): - addl $(VEC_SIZE * 2), %esi - VPCMPEQ (%rdi), %ymm0, %ymm1 - vpmovmskb %ymm1, %eax - testl %eax, %eax +L(last_4x_vec_or_less_load): + /* Depending on entry adjust rdi / prepare first VEC in ymm1. */ + subq $-(VEC_SIZE * 4), %rdi +L(last_4x_vec_or_less_cmpeq): + VPCMPEQ 1(%rdi), %ymm0, %ymm1 +L(last_4x_vec_or_less): - jnz L(first_vec_x0_check) - subl $VEC_SIZE, %esi - jle L(max) + vpmovmskb %ymm1, %eax + /* If remaining length > VEC_SIZE * 2. This works if esi is off by + VEC_SIZE * 4. */ + testl $(VEC_SIZE * 2), %esi + jnz L(last_4x_vec) - VPCMPEQ VEC_SIZE(%rdi), %ymm0, %ymm1 - vpmovmskb %ymm1, %eax + /* length may have been negative or positive by an offset of + VEC_SIZE * 4 depending on where this was called from. This fixes + that. */ + andl $(VEC_SIZE * 4 - 1), %esi testl %eax, %eax - jnz L(first_vec_x1_check) - movq %r8, %rax -# ifdef USE_AS_WCSLEN - shrq $2, %rax -# endif - VZEROUPPER_RETURN + jnz L(last_vec_x1_check) - .p2align 4 -L(first_vec_x0_check): + subl $VEC_SIZE, %esi + jb L(max) + + VPCMPEQ (VEC_SIZE + 1)(%rdi), %ymm0, %ymm1 + vpmovmskb %ymm1, %eax tzcntl %eax, %eax /* Check the end of data. */ - cmpq %rax, %rsi - jbe L(max) + cmpl %eax, %esi + jb L(max) + subq %rdx, %rdi + addl $(VEC_SIZE + 1), %eax addq %rdi, %rax - subq %rdx, %rax # ifdef USE_AS_WCSLEN shrq $2, %rax # endif VZEROUPPER_RETURN +# endif .p2align 4 -L(first_vec_x1_check): +L(last_vec_return_x0): tzcntl %eax, %eax - /* Check the end of data. */ - cmpq %rax, %rsi - jbe L(max) - addq $VEC_SIZE, %rax + subq $(VEC_SIZE * 4 - 1), %rdi addq %rdi, %rax - subq %rdx, %rax -# ifdef USE_AS_WCSLEN +# ifdef USE_AS_WCSLEN shrq $2, %rax -# endif +# endif VZEROUPPER_RETURN .p2align 4 -L(first_vec_x2_check): +L(last_vec_return_x1): tzcntl %eax, %eax - /* Check the end of data. */ - cmpq %rax, %rsi - jbe L(max) - addq $(VEC_SIZE * 2), %rax + subq $(VEC_SIZE * 3 - 1), %rdi addq %rdi, %rax - subq %rdx, %rax -# ifdef USE_AS_WCSLEN +# ifdef USE_AS_WCSLEN shrq $2, %rax -# endif +# endif VZEROUPPER_RETURN +# ifdef USE_AS_STRNLEN .p2align 4 -L(first_vec_x3_check): +L(last_vec_x1_check): + tzcntl %eax, %eax /* Check the end of data. */ - cmpq %rax, %rsi - jbe L(max) - addq $(VEC_SIZE * 3), %rax + cmpl %eax, %esi + jb L(max) + subq %rdx, %rdi + incl %eax addq %rdi, %rax - subq %rdx, %rax # ifdef USE_AS_WCSLEN shrq $2, %rax # endif VZEROUPPER_RETURN - .p2align 4 L(max): movq %r8, %rax + VZEROUPPER_RETURN + + .p2align 4 +L(last_4x_vec): + /* Test first 2x VEC normally. */ + testl %eax, %eax + jnz L(last_vec_x1) + + VPCMPEQ (VEC_SIZE + 1)(%rdi), %ymm0, %ymm1 + vpmovmskb %ymm1, %eax + testl %eax, %eax + jnz L(last_vec_x2) + + /* Normalize length. */ + andl $(VEC_SIZE * 4 - 1), %esi + VPCMPEQ (VEC_SIZE * 2 + 1)(%rdi), %ymm0, %ymm1 + vpmovmskb %ymm1, %eax + testl %eax, %eax + jnz L(last_vec_x3) + + subl $(VEC_SIZE * 3), %esi + jb L(max) + + VPCMPEQ (VEC_SIZE * 3 + 1)(%rdi), %ymm0, %ymm1 + vpmovmskb %ymm1, %eax + tzcntl %eax, %eax + /* Check the end of data. */ + cmpl %eax, %esi + jb L(max) + subq %rdx, %rdi + addl $(VEC_SIZE * 3 + 1), %eax + addq %rdi, %rax # ifdef USE_AS_WCSLEN shrq $2, %rax # endif VZEROUPPER_RETURN - .p2align 4 -L(zero): - xorl %eax, %eax - ret -# endif .p2align 4 -L(first_vec_x0): +L(last_vec_x1): + /* essentially duplicates of first_vec_x1 but use 64 bit + instructions. */ tzcntl %eax, %eax + subq %rdx, %rdi + incl %eax addq %rdi, %rax - subq %rdx, %rax -# ifdef USE_AS_WCSLEN +# ifdef USE_AS_WCSLEN shrq $2, %rax -# endif +# endif VZEROUPPER_RETURN .p2align 4 -L(first_vec_x1): +L(last_vec_x2): + /* essentially duplicates of first_vec_x1 but use 64 bit + instructions. */ tzcntl %eax, %eax - addq $VEC_SIZE, %rax + subq %rdx, %rdi + addl $(VEC_SIZE + 1), %eax addq %rdi, %rax - subq %rdx, %rax -# ifdef USE_AS_WCSLEN +# ifdef USE_AS_WCSLEN shrq $2, %rax -# endif +# endif VZEROUPPER_RETURN .p2align 4 -L(first_vec_x2): +L(last_vec_x3): tzcntl %eax, %eax - addq $(VEC_SIZE * 2), %rax + subl $(VEC_SIZE * 2), %esi + /* Check the end of data. */ + cmpl %eax, %esi + jb L(max_end) + subq %rdx, %rdi + addl $(VEC_SIZE * 2 + 1), %eax addq %rdi, %rax - subq %rdx, %rax -# ifdef USE_AS_WCSLEN +# ifdef USE_AS_WCSLEN shrq $2, %rax -# endif +# endif + VZEROUPPER_RETURN +L(max_end): + movq %r8, %rax VZEROUPPER_RETURN +# endif + /* Cold case for crossing page with first load. */ .p2align 4 -L(4x_vec_end): - VPCMPEQ %ymm1, %ymm0, %ymm1 - vpmovmskb %ymm1, %eax - testl %eax, %eax - jnz L(first_vec_x0) - VPCMPEQ %ymm2, %ymm0, %ymm2 - vpmovmskb %ymm2, %eax +L(cross_page_boundary): + /* Align data to VEC_SIZE - 1. */ + orq $(VEC_SIZE - 1), %rdi + VPCMPEQ -(VEC_SIZE - 1)(%rdi), %ymm0, %ymm1 + vpmovmskb %ymm1, %eax + /* Remove the leading bytes. sarxl only uses bits [5:0] of COUNT + so no need to manually mod rdx. */ + sarxl %edx, %eax, %eax +# ifdef USE_AS_STRNLEN testl %eax, %eax - jnz L(first_vec_x1) - VPCMPEQ %ymm3, %ymm0, %ymm3 - vpmovmskb %ymm3, %eax + jnz L(cross_page_less_vec) + leaq 1(%rdi), %rcx + subq %rdx, %rcx + /* Check length. */ + cmpq %rsi, %rcx + jb L(cross_page_continue) + movq %r8, %rax +# else testl %eax, %eax - jnz L(first_vec_x2) - VPCMPEQ %ymm4, %ymm0, %ymm4 - vpmovmskb %ymm4, %eax -L(first_vec_x3): + jz L(cross_page_continue) tzcntl %eax, %eax - addq $(VEC_SIZE * 3), %rax - addq %rdi, %rax - subq %rdx, %rax -# ifdef USE_AS_WCSLEN - shrq $2, %rax +# ifdef USE_AS_WCSLEN + shrl $2, %eax +# endif # endif +L(return_vzeroupper): + ZERO_UPPER_VEC_REGISTERS_RETURN + +# ifdef USE_AS_STRNLEN + .p2align 4 +L(cross_page_less_vec): + tzcntl %eax, %eax + cmpq %rax, %rsi + cmovb %esi, %eax +# ifdef USE_AS_WCSLEN + shrl $2, %eax +# endif VZEROUPPER_RETURN +# endif END (STRLEN) #endif |