1993-12-04 06:05:16 +03:00
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/*
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1995-10-07 12:26:14 +03:00
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* Written by J.T. Conklin <jtc@netbsd.org>.
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* Public domain.
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1993-12-04 06:05:16 +03:00
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*/
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1995-02-05 18:06:43 +03:00
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#include <machine/asm.h>
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1993-12-04 06:05:16 +03:00
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#if defined(LIBC_SCCS)
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1998-02-22 11:14:56 +03:00
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RCSID("$NetBSD: bzero.S,v 1.6 1998/02/22 08:14:57 mycroft Exp $")
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1993-12-04 06:05:16 +03:00
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#endif
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ENTRY(bzero)
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pushl %edi
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1995-02-05 18:06:43 +03:00
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movl 8(%esp),%edi
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movl 12(%esp),%edx
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1993-12-04 06:05:16 +03:00
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cld /* set fill direction forward */
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xorl %eax,%eax /* set fill data to 0 */
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/*
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* if the string is too short, it's really not worth the overhead
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* of aligning to word boundries, etc. So we jump to a plain
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* unaligned set.
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*/
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1995-02-05 18:06:43 +03:00
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cmpl $16,%edx
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jb L1
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1993-12-04 06:05:16 +03:00
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1995-02-05 18:06:43 +03:00
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movl %edi,%ecx /* compute misalignment */
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negl %ecx
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andl $3,%ecx
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subl %ecx,%edx
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rep /* zero until word aligned */
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1993-12-04 06:05:16 +03:00
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stosb
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1995-02-05 18:06:43 +03:00
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movl %edx,%ecx /* zero by words */
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1993-12-04 06:05:16 +03:00
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shrl $2,%ecx
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1995-02-05 18:06:43 +03:00
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andl $3,%edx
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1993-12-04 06:05:16 +03:00
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rep
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stosl
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1995-02-05 18:06:43 +03:00
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L1: movl %edx,%ecx /* zero remainder by bytes */
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rep
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1993-12-04 06:05:16 +03:00
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stosb
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popl %edi
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ret
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