diff options
Diffstat (limited to 'libc/arch-x86/string/strcmp.S')
| -rw-r--r-- | libc/arch-x86/string/strcmp.S | 81 |
1 files changed, 81 insertions, 0 deletions
diff --git a/libc/arch-x86/string/strcmp.S b/libc/arch-x86/string/strcmp.S new file mode 100644 index 0000000..22ba546 --- /dev/null +++ b/libc/arch-x86/string/strcmp.S @@ -0,0 +1,81 @@ +/* $OpenBSD: strcmp.S,v 1.3 2005/08/07 11:30:38 espie Exp $ */ +/* + * Written by J.T. Conklin <jtc@netbsd.org>. + * Public domain. + */ + +#include <machine/asm.h> + +/* + * NOTE: I've unrolled the loop eight times: large enough to make a + * significant difference, and small enough not to totally trash the + * cache. + */ + +ENTRY(strcmp) + movl 0x04(%esp),%eax + movl 0x08(%esp),%edx + jmp L2 /* Jump into the loop! */ + + .align 2,0x90 +L1: incl %eax + incl %edx +L2: movb (%eax),%cl + testb %cl,%cl /* null terminator??? */ + jz L3 + cmpb %cl,(%edx) /* chars match??? */ + jne L3 + incl %eax + incl %edx + movb (%eax),%cl + testb %cl,%cl + jz L3 + cmpb %cl,(%edx) + jne L3 + incl %eax + incl %edx + movb (%eax),%cl + testb %cl,%cl + jz L3 + cmpb %cl,(%edx) + jne L3 + incl %eax + incl %edx + movb (%eax),%cl + testb %cl,%cl + jz L3 + cmpb %cl,(%edx) + jne L3 + incl %eax + incl %edx + movb (%eax),%cl + testb %cl,%cl + jz L3 + cmpb %cl,(%edx) + jne L3 + incl %eax + incl %edx + movb (%eax),%cl + testb %cl,%cl + jz L3 + cmpb %cl,(%edx) + jne L3 + incl %eax + incl %edx + movb (%eax),%cl + testb %cl,%cl + jz L3 + cmpb %cl,(%edx) + jne L3 + incl %eax + incl %edx + movb (%eax),%cl + testb %cl,%cl + jz L3 + cmpb %cl,(%edx) + je L1 + .align 2, 0x90 +L3: movzbl (%eax),%eax /* unsigned comparison */ + movzbl (%edx),%edx + subl %edx,%eax + ret |