1/* 2 * Copyright (c) 1993 Winning Strategies, Inc. 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by Winning Strategies, Inc. 16 * 4. The name of the author may not be used to endorse or promote products 17 * derived from this software without specific prior written permission 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 20 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 21 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 22 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 23 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 24 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 28 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29 * 30 * $Id: memset.S,v 1.2 1994/03/31 14:11:01 davidg Exp $ 31 */ 32 33#if defined(LIBC_RCS) && !defined(lint) 34 .asciz "$Id: memset.S,v 1.2 1994/03/31 14:11:01 davidg Exp $" 35#endif /* LIBC_RCS and not lint */ 36 37#include "DEFS.h" 38 39/* 40 * memset(void *b, int c, size_t len) 41 * write len bytes of value c (converted to an unsigned char) to 42 * the string b. 43 * 44 * Written by: 45 * J.T. Conklin (jtc@wimsey.com), Winning Strategies, Inc. 46 */ 47 48ENTRY(memset) 49 pushl %edi 50 pushl %ebx 51 movl 12(%esp),%edi 52 movzbl 16(%esp),%eax /* unsigned char, zero extend */ 53 movl 20(%esp),%ecx 54 pushl %edi /* push address of buffer */ 55 56 cld /* set fill direction forward */ 57 58 /* 59 * if the string is too short, it's really not worth the overhead 60 * of aligning to word boundries, etc. So we jump to a plain 61 * unaligned set. 62 */ 63 cmpl $0x0f,%ecx 64 jle L1 65 66 movb %al,%ah /* copy char to all bytes in word */ 67 movl %eax,%edx 68 sall $16,%eax 69 orl %edx,%eax 70 71 movl %edi,%edx /* compute misalignment */ 72 negl %edx 73 andl $3,%edx 74 movl %ecx,%ebx 75 subl %edx,%ebx 76 77 movl %edx,%ecx /* set until word aligned */ 78 rep 79 stosb 80 81 movl %ebx,%ecx 82 shrl $2,%ecx /* set by words */ 83 rep 84 stosl 85 86 movl %ebx,%ecx /* set remainder by bytes */ 87 andl $3,%ecx 88L1: rep 89 stosb 90 91 popl %eax /* pop address of buffer */ 92 popl %ebx 93 popl %edi 94 ret 95