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| author | H.J. Lu <hongjiu.lu@intel.com> | 2010-08-26 22:09:34 -0700 |
|---|---|---|
| committer | Ulrich Drepper <drepper@redhat.com> | 2010-08-26 22:09:34 -0700 |
| commit | 623aac7f84dfddee9bcf9d51f23612479cf672ec (patch) | |
| tree | 355c57e1d98cff706ead0832461b060bc24ffc7c /sysdeps/x86_64/strlen.S | |
| parent | b416a900856ff871c06b08fa2c9c943fd86597da (diff) | |
| download | glibc-623aac7f84dfddee9bcf9d51f23612479cf672ec.tar.gz glibc-623aac7f84dfddee9bcf9d51f23612479cf672ec.tar.xz glibc-623aac7f84dfddee9bcf9d51f23612479cf672ec.zip | |
Unroll x86-64 strlen
Diffstat (limited to 'sysdeps/x86_64/strlen.S')
| -rw-r--r-- | sysdeps/x86_64/strlen.S | 97 |
1 files changed, 76 insertions, 21 deletions
diff --git a/sysdeps/x86_64/strlen.S b/sysdeps/x86_64/strlen.S index 93aee6bef1..7880c1d5e5 100644 --- a/sysdeps/x86_64/strlen.S +++ b/sysdeps/x86_64/strlen.S @@ -1,6 +1,7 @@ /* strlen(str) -- determine the length of the string STR. - Copyright (C) 2009 Free Software Foundation, Inc. + Copyright (C) 2009, 2010 Free Software Foundation, Inc. Contributed by Ulrich Drepper <drepper@redhat.com>. + Modified by Intel Corporation. This file is part of the GNU C Library. The GNU C Library is free software; you can redistribute it and/or @@ -23,29 +24,83 @@ .text ENTRY(strlen) - pxor %xmm2, %xmm2 - movq %rdi, %rcx - movq %rdi, %r8 - andq $~15, %rdi - movdqa %xmm2, %xmm1 - pcmpeqb (%rdi), %xmm2 - orl $0xffffffff, %esi - subq %rdi, %rcx - shll %cl, %esi - pmovmskb %xmm2, %edx - andl %esi, %edx - jnz 1f - -2: movdqa 16(%rdi), %xmm0 - leaq 16(%rdi), %rdi + xor %rax, %rax + mov %edi, %ecx + and $0x3f, %ecx + pxor %xmm0, %xmm0 + cmp $0x30, %ecx + ja L(next) + movdqu (%rdi), %xmm1 pcmpeqb %xmm1, %xmm0 pmovmskb %xmm0, %edx - testl %edx, %edx - jz 2b + test %edx, %edx + jnz L(exit_less16) + mov %rdi, %rax + and $-16, %rax + jmp L(align16_start) +L(next): + mov %rdi, %rax + and $-16, %rax + pcmpeqb (%rax), %xmm0 + mov $-1, %esi + sub %rax, %rcx + shl %cl, %esi + pmovmskb %xmm0, %edx + and %esi, %edx + jnz L(exit) +L(align16_start): + pxor %xmm0, %xmm0 + pxor %xmm1, %xmm1 + pxor %xmm2, %xmm2 + pxor %xmm3, %xmm3 + .p2align 4 +L(align16_loop): + pcmpeqb 16(%rax), %xmm0 + pmovmskb %xmm0, %edx + test %edx, %edx + jnz L(exit16) -1: subq %r8, %rdi - bsfl %edx, %eax - addq %rdi, %rax + pcmpeqb 32(%rax), %xmm1 + pmovmskb %xmm1, %edx + test %edx, %edx + jnz L(exit32) + + pcmpeqb 48(%rax), %xmm2 + pmovmskb %xmm2, %edx + test %edx, %edx + jnz L(exit48) + + pcmpeqb 64(%rax), %xmm3 + pmovmskb %xmm3, %edx + lea 64(%rax), %rax + test %edx, %edx + jz L(align16_loop) +L(exit): + sub %rdi, %rax +L(exit_less16): + bsf %rdx, %rdx + add %rdx, %rax + ret + .p2align 4 +L(exit16): + sub %rdi, %rax + bsf %rdx, %rdx + add %rdx, %rax + add $16, %rax + ret + .p2align 4 +L(exit32): + sub %rdi, %rax + bsf %rdx, %rdx + add %rdx, %rax + add $32, %rax + ret + .p2align 4 +L(exit48): + sub %rdi, %rax + bsf %rdx, %rdx + add %rdx, %rax + add $48, %rax ret END(strlen) libc_hidden_builtin_def (strlen) |