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/*
* Written by J.T. Conklin <jtc@netbsd.org>.
* Public domain.
*/
#include <machine/asm.h>
#if defined(LIBC_SCCS)
.text
.asciz "$OpenBSD: strncmp.S,v 1.2 1996/08/19 08:13:21 tholo Exp $"
#endif
/*
* 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(strncmp)
pushl %ebx
movl 8(%esp),%eax
movl 12(%esp),%ecx
movl 16(%esp),%edx
testl %edx,%edx
jmp L2 /* Jump into the loop! */
.align 2,0x90
L1: incl %eax
incl %ecx
decl %edx
L2: jz L4 /* strings are equal */
movb (%eax),%bl
testb %bl,%bl
jz L3
cmpb %bl,(%ecx)
jne L3
incl %eax
incl %ecx
decl %edx
jz L4
movb (%eax),%bl
testb %bl,%bl
jz L3
cmpb %bl,(%ecx)
jne L3
incl %eax
incl %ecx
decl %edx
jz L4
movb (%eax),%bl
testb %bl,%bl
jz L3
cmpb %bl,(%ecx)
jne L3
incl %eax
incl %ecx
decl %edx
jz L4
movb (%eax),%bl
testb %bl,%bl
jz L3
cmpb %bl,(%ecx)
jne L3
incl %eax
incl %ecx
decl %edx
jz L4
movb (%eax),%bl
testb %bl,%bl
jz L3
cmpb %bl,(%ecx)
jne L3
incl %eax
incl %ecx
decl %edx
jz L4
movb (%eax),%bl
testb %bl,%bl
jz L3
cmpb %bl,(%ecx)
jne L3
incl %eax
incl %ecx
decl %edx
jz L4
movb (%eax),%bl
testb %bl,%bl
jz L3
cmpb %bl,(%ecx)
jne L3
incl %eax
incl %ecx
decl %edx
jz L4
movb (%eax),%bl
testb %bl,%bl
jz L3
cmpb %bl,(%ecx)
je L1
.align 2,0x90
L3: movzbl (%eax),%eax /* unsigned comparision */
movzbl (%ecx),%ecx
subl %ecx,%eax
popl %ebx
ret
.align 2,0x90
L4: xorl %eax,%eax
popl %ebx
ret
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