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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: bzero.S,v 1.1 2001/06/19 00:22:45 fvdl Exp $")
#endif
ENTRY(bzero)
movq %rsi,%rdx
cld /* set fill direction forward */
xorq %rax,%rax /* set fill data to 0 */
/*
* if the string is too short, it's really not worth the overhead
* of aligning to word boundries, etc. So we jump to a plain
* unaligned set.
*/
cmpq $16,%rdx
jb L1
movq %rdi,%rcx /* compute misalignment */
negq %rcx
andq $7,%rcx
subq %rcx,%rdx
rep /* zero until word aligned */
stosb
movq %rdx,%rcx /* zero by words */
shrq $3,%rcx
andq $7,%rdx
rep
stosq
L1: movq %rdx,%rcx /* zero remainder by bytes */
rep
stosb
ret
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