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- /* $OpenBSD: bzero.S,v 1.5 2014/11/29 18:51:23 tedu Exp $ */
- /*
- * Written by J.T. Conklin <jtc@netbsd.org>.
- * Public domain.
- */
- #include <machine/asm.h>
- #ifndef _KERNEL
- ENTRY(bzero)
- pushl %edi
- movl 8(%esp),%edi
- movl 12(%esp),%edx
- xorl %eax,%eax /* set fill data to 0 */
- /*
- * if the string is too short, it's really not worth the overhead
- * of aligning to word boundaries, etc. So we jump to a plain
- * unaligned set.
- */
- cmpl $16,%edx
- jb L1
- movl %edi,%ecx /* compute misalignment */
- negl %ecx
- andl $3,%ecx
- subl %ecx,%edx
- rep /* zero until word aligned */
- stosb
- movl %edx,%ecx /* zero by words */
- shrl $2,%ecx
- andl $3,%edx
- rep
- stosl
- L1: movl %edx,%ecx /* zero remainder by bytes */
- rep
- stosb
- popl %edi
- ret
- #endif
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