/*      $OpenBSD: bzero.S,v 1.6 2022/08/22 09:33:40 jsg Exp $   */

/*
 * Written by J.T. Conklin <jtc@netbsd.org>.
 * Public domain.
 */

#include <machine/asm.h>

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