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>
.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