1993-10-07 03:17:24 +03:00
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/*
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* Copyright (c) 1993 Winning Strategies, Inc.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by Winning Strategies, Inc.
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* 4. The name of the author may not be used to endorse or promote products
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1994-01-28 23:34:33 +03:00
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* derived from this software without specific prior written permission
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1993-10-07 03:17:24 +03:00
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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1994-01-28 23:34:33 +03:00
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* $Id: bzero.S,v 1.4 1994/01/28 20:34:35 jtc Exp $
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1993-10-07 03:17:24 +03:00
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*/
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1993-10-21 04:39:55 +03:00
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#if defined(LIBC_SCCS)
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1993-10-07 03:17:24 +03:00
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.text
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1994-01-28 23:34:33 +03:00
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.asciz "$Id: bzero.S,v 1.4 1994/01/28 20:34:35 jtc Exp $"
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1993-10-21 04:39:55 +03:00
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#endif
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1993-10-07 03:17:24 +03:00
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#include "DEFS.h"
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/*
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* bzero (void *b, size_t len)
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* write len zero bytes to the string b.
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*
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* Written by:
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* J.T. Conklin (jtc@wimsey.com), Winning Strategies, Inc.
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*/
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ENTRY(bzero)
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pushl %edi
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pushl %ebx
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movl 12(%esp),%edi
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movl 16(%esp),%ecx
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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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1993-10-21 04:48:14 +03:00
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* of aligning to word boundries, etc. So we jump to a plain
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1993-10-07 03:17:24 +03:00
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* unaligned set.
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*/
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cmpl $0x0f,%ecx
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jle L1
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movl %edi,%edx /* compute misalignment */
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negl %edx
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andl $3,%edx
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movl %ecx,%ebx
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subl %edx,%ebx
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movl %edx,%ecx /* zero until word aligned */
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rep
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stosb
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movl %ebx,%ecx /* zero by words */
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shrl $2,%ecx
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rep
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stosl
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movl %ebx,%ecx
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andl $3,%ecx /* zero remainder by bytes */
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L1: rep
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stosb
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popl %ebx
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popl %edi
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ret
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