minix/lib/nbsd_libc/arch/x86_64/string/strncmp.S
Gianluca Guida b6cbf7203b Import unmodified NetBSD libc in trunk
This patch imports the unmodified current version of NetBSD libc.
The NetBSD includes are in /nbsd_include, while the libc code itself is 
split between lib/nbsd_libc and common/lib/libc.
2011-02-14 19:36:03 +00:00

107 lines
1.4 KiB
ArmAsm

/*
* Written by J.T. Conklin <jtc@NetBSD.org>.
* Public domain.
*/
#include <machine/asm.h>
#if defined(LIBC_SCCS)
RCSID("$NetBSD: strncmp.S,v 1.3 2005/08/03 22:59:50 rpaulo 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)
testq %rdx,%rdx
jmp L2 /* Jump into the loop! */
L1: incq %rdi
incq %rsi
decq %rdx
L2: jz L4 /* strings are equal */
movb (%rdi),%al
testb %al,%al
jz L3
cmpb %al,(%rsi)
jne L3
incq %rdi
incq %rsi
decq %rdx
jz L4
movb (%rdi),%al
testb %al,%al
jz L3
cmpb %al,(%rsi)
jne L3
incq %rdi
incq %rsi
decq %rdx
jz L4
movb (%rdi),%al
testb %al,%al
jz L3
cmpb %al,(%rsi)
jne L3
incq %rdi
incq %rsi
decq %rdx
jz L4
movb (%rdi),%al
testb %al,%al
jz L3
cmpb %al,(%rsi)
jne L3
incq %rdi
incq %rsi
decq %rdx
jz L4
movb (%rdi),%al
testb %al,%al
jz L3
cmpb %al,(%rsi)
jne L3
incq %rdi
incq %rsi
decq %rdx
jz L4
movb (%rdi),%al
testb %al,%al
jz L3
cmpb %al,(%rsi)
jne L3
incq %rdi
incq %rsi
decq %rdx
jz L4
movb (%rdi),%al
testb %al,%al
jz L3
cmpb %al,(%rsi)
jne L3
incq %rdi
incq %rsi
decq %rdx
jz L4
movb (%rdi),%al
testb %al,%al
jz L3
cmpb %al,(%rsi)
je L1
L3: movzbl (%rdi),%eax /* unsigned comparison */
movzbl (%rsi),%ecx
subl %ecx,%eax
ret
L4: xorl %eax,%eax
ret