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authorUlrich Drepper <drepper@redhat.com>2009-06-04 16:45:35 -0700
committerUlrich Drepper <drepper@redhat.com>2009-06-04 16:45:35 -0700
commit2f3f7b9da238269397d8dd8868ed494eff2c9064 (patch)
tree86f742588aa98f969fd357c5be0a57128a11e2cb /sysdeps/x86_64/strlen.S
parent747785f2b3afbc8b900083988957bff11bb6b11f (diff)
downloadglibc-2f3f7b9da238269397d8dd8868ed494eff2c9064.tar.gz
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More small optimizations for x86-64 strlen.
Diffstat (limited to 'sysdeps/x86_64/strlen.S')
-rw-r--r--sysdeps/x86_64/strlen.S16
1 files changed, 7 insertions, 9 deletions
diff --git a/sysdeps/x86_64/strlen.S b/sysdeps/x86_64/strlen.S
index 572f3c2e41..93aee6bef1 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