strcat.S revision 50476
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 withough 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 * $FreeBSD: head/lib/libc/i386/string/strcat.S 50476 1999-08-28 00:22:10Z peter $ 31 */ 32 33#if defined(LIBC_RCS) && !defined(lint) 34 .text 35 .asciz "$FreeBSD: head/lib/libc/i386/string/strcat.S 50476 1999-08-28 00:22:10Z peter $" 36#endif /* LIBC_RCS and not lint */ 37 38#include "DEFS.h" 39 40/* 41 * strcat(s, append) 42 * append a copy of the null-terminated string "append" to the end 43 * of the null-terminated string s, then add a terminating `\0'. 44 * 45 * Written by: 46 * J.T. Conklin (jtc@wimsey.com), Winning Strategies, Inc. 47 */ 48 49/* 50 * I've unrolled the loop eight times: large enough to make a 51 * significant difference, and small enough not to totally trash the 52 * cashe. 53 */ 54 55ENTRY(strcat) 56 pushl %edi /* save edi */ 57 movl 8(%esp),%edi /* dst address */ 58 movl 12(%esp),%edx /* src address */ 59 pushl %edi /* push destination address */ 60 61 cld /* set search forward */ 62 xorl %eax,%eax /* set search for null terminator */ 63 movl $-1,%ecx /* set search for lots of characters */ 64 repne /* search! */ 65 scasb 66 67 leal -1(%edi),%ecx /* correct dst address */ 68 69 .align 2,0x90 70L1: movb (%edx),%al /* unroll loop, but not too much */ 71 movb %al,(%ecx) 72 testb %al,%al 73 je L2 74 movb 1(%edx),%al 75 movb %al,1(%ecx) 76 testb %al,%al 77 je L2 78 movb 2(%edx),%al 79 movb %al,2(%ecx) 80 testb %al,%al 81 je L2 82 movb 3(%edx),%al 83 movb %al,3(%ecx) 84 testb %al,%al 85 je L2 86 movb 4(%edx),%al 87 movb %al,4(%ecx) 88 testb %al,%al 89 je L2 90 movb 5(%edx),%al 91 movb %al,5(%ecx) 92 testb %al,%al 93 je L2 94 movb 6(%edx),%al 95 movb %al,6(%ecx) 96 testb %al,%al 97 je L2 98 movb 7(%edx),%al 99 movb %al,7(%ecx) 100 addl $8,%edx 101 addl $8,%ecx 102 testb %al,%al 103 jne L1 104L2: popl %eax /* pop destination address */ 105 popl %edi /* restore edi */ 106 ret 107