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/*
* Written by J.T. Conklin <jtc@netbsd.org>.
* Public domain.
* Adapted for NetBSD/x86_64 by Frank van der Linden <fvdl@wasabisystems.com>
*/
#include <machine/asm.h>
#if defined(LIBC_SCCS)
RCSID("$NetBSD: strcat.S,v 1.1 2001/06/19 00:22:47 fvdl 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(strcat)
movq %rdi,%r11
cld /* set search forward */
xorl %eax,%eax /* set search for null terminator */
movq $-1,%rcx /* set search for lots of characters */
repne /* search! */
scasb
decq %rdi
L1: movb (%rsi),%al /* unroll loop, but not too much */
movb %al,(%rdi)
testb %al,%al
jz L2
movb 1(%rsi),%al
movb %al,1(%rdi)
testb %al,%al
jz L2
movb 2(%rsi),%al
movb %al,2(%rdi)
testb %al,%al
jz L2
movb 3(%rsi),%al
movb %al,3(%rdi)
testb %al,%al
jz L2
movb 4(%rsi),%al
movb %al,4(%rdi)
testb %al,%al
jz L2
movb 5(%rsi),%al
movb %al,5(%rdi)
testb %al,%al
jz L2
movb 6(%rsi),%al
movb %al,6(%rdi)
testb %al,%al
jz L2
movb 7(%rsi),%al
movb %al,7(%rdi)
addq $8,%rsi
addq $8,%rdi
testb %al,%al
jnz L1
L2: movq %r11,%rax
ret
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