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| author | Ulrich Drepper <drepper@redhat.com> | 2009-06-04 16:45:35 -0700 |
|---|---|---|
| committer | Ulrich Drepper <drepper@redhat.com> | 2009-06-04 16:45:35 -0700 |
| commit | 2f3f7b9da238269397d8dd8868ed494eff2c9064 (patch) | |
| tree | 86f742588aa98f969fd357c5be0a57128a11e2cb | |
| parent | 747785f2b3afbc8b900083988957bff11bb6b11f (diff) | |
| download | glibc-2f3f7b9da238269397d8dd8868ed494eff2c9064.zip glibc-2f3f7b9da238269397d8dd8868ed494eff2c9064.tar.gz glibc-2f3f7b9da238269397d8dd8868ed494eff2c9064.tar.bz2 | |
More small optimizations for x86-64 strlen.
| -rw-r--r-- | ChangeLog | 2 | ||||
| -rw-r--r-- | sysdeps/x86_64/strlen.S | 16 |
2 files changed, 8 insertions, 10 deletions
@@ -1,6 +1,6 @@ 2009-06-04 Ulrich Drepper <drepper@redhat.com> - * sysdeps/x86_64/strlen.S: Remove useless instruction. + * sysdeps/x86_64/strlen.S: Minor optimizations. 2009-06-02 H.J. Lu <hongjiu.lu@intel.com> diff --git a/sysdeps/x86_64/strlen.S b/sysdeps/x86_64/strlen.S index 572f3c2..93aee6b 100644 --- a/sysdeps/x86_64/strlen.S +++ b/sysdeps/x86_64/strlen.S @@ -23,29 +23,27 @@ .text ENTRY(strlen) + pxor %xmm2, %xmm2 movq %rdi, %rcx movq %rdi, %r8 andq $~15, %rdi - pxor %xmm1, %xmm1 + movdqa %xmm2, %xmm1 + pcmpeqb (%rdi), %xmm2 orl $0xffffffff, %esi - movdqa (%rdi), %xmm0 subq %rdi, %rcx - leaq 16(%rdi), %rdi - pcmpeqb %xmm1, %xmm0 - shl %cl, %esi - pmovmskb %xmm0, %edx - negq %r8 + shll %cl, %esi + pmovmskb %xmm2, %edx andl %esi, %edx jnz 1f -2: movdqa (%rdi), %xmm0 +2: movdqa 16(%rdi), %xmm0 leaq 16(%rdi), %rdi pcmpeqb %xmm1, %xmm0 pmovmskb %xmm0, %edx testl %edx, %edx jz 2b -1: leaq -16(%rdi,%r8), %rdi +1: subq %r8, %rdi bsfl %edx, %eax addq %rdi, %rax ret |