strncmp.S revision 1849
1/* 2 * Copyright (c) 1993,94 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: strncmp.S,v 1.3 1994/03/31 14:11:02 davidg Exp $ 31 */ 32 33#if defined(LIBC_RCS) && !defined(lint) 34 .asciz "$Id: strncmp.S,v 1.3 1994/03/31 14:11:02 davidg Exp $" 35#endif /* LIBC_RCS and not lint */ 36 37#include "DEFS.h" 38 39/* 40 * strncmp(s1, s2, n) 41 * return an integer greater than, equal to, or less than 0, 42 * according as the first n characters of string s1 is greater 43 * than, equal to, or less than the string s2. 44 * 45 * %eax - pointer to s1 46 * %ecx - pointer to s2 47 * %edx - length 48 * 49 * Written by: 50 * J.T. Conklin (jtc@wimsey.com), Winning Strategies, Inc. 51 */ 52 53/* 54 * I've unrolled the loop eight times: large enough to make a 55 * significant difference, and small enough not to totally trash the 56 * cache. 57 */ 58 59ENTRY(strncmp) 60 pushl %ebx 61 movl 8(%esp),%eax 62 movl 12(%esp),%ecx 63 movl 16(%esp),%edx 64 testl %edx,%edx 65 jmp L2 /* Jump into the loop! */ 66 67 .align 2,0x90 68L1: incl %eax 69 incl %ecx 70 decl %edx 71L2: jz L4 /* strings are equal */ 72 movb (%eax),%bl 73 testb %bl,%bl 74 jz L3 75 cmpb %bl,(%ecx) 76 jne L3 77 78 incl %eax 79 incl %ecx 80 decl %edx 81 jz L4 82 movb (%eax),%bl 83 testb %bl,%bl 84 jz L3 85 cmpb %bl,(%ecx) 86 jne L3 87 88 incl %eax 89 incl %ecx 90 decl %edx 91 jz L4 92 movb (%eax),%bl 93 testb %bl,%bl 94 jz L3 95 cmpb %bl,(%ecx) 96 jne L3 97 98 incl %eax 99 incl %ecx 100 decl %edx 101 jz L4 102 movb (%eax),%bl 103 testb %bl,%bl 104 jz L3 105 cmpb %bl,(%ecx) 106 jne L3 107 108 incl %eax 109 incl %ecx 110 decl %edx 111 jz L4 112 movb (%eax),%bl 113 testb %bl,%bl 114 jz L3 115 cmpb %bl,(%ecx) 116 jne L3 117 118 incl %eax 119 incl %ecx 120 decl %edx 121 jz L4 122 movb (%eax),%bl 123 testb %bl,%bl 124 jz L3 125 cmpb %bl,(%ecx) 126 jne L3 127 128 incl %eax 129 incl %ecx 130 decl %edx 131 jz L4 132 movb (%eax),%bl 133 testb %bl,%bl 134 jz L3 135 cmpb %bl,(%ecx) 136 jne L3 137 138 incl %eax 139 incl %ecx 140 decl %edx 141 jz L4 142 movb (%eax),%bl 143 testb %bl,%bl 144 jz L3 145 cmpb %bl,(%ecx) 146 je L1 147 148 .align 2,0x90 149L3: movzbl (%eax),%eax /* unsigned comparision */ 150 movzbl (%ecx),%ecx 151 subl %ecx,%eax 152 popl %ebx 153 ret 154 .align 2,0x90 155L4: xorl %eax,%eax 156 popl %ebx 157 ret 158