strncmp.S revision 1.7
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 1.7 1994/02/14 17:44:39 jtc Exp $ 31 */ 32 33 #if defined(LIBC_SCCS) 34 .text 35 .asciz "$Id: strncmp.S,v 1.7 1994/02/14 17:44:39 jtc Exp $" 36 #endif 37 38 #include <machine/asm.h> 39 40 /* 41 * strncmp(s1, s2, n) 42 * return an integer greater than, equal to, or less than 0, 43 * according as the first n characters of string s1 is greater 44 * than, equal to, or less than the string s2. 45 * 46 * %eax - pointer to s1 47 * %ecx - pointer to s2 48 * %edx - length 49 * 50 * Written by: 51 * J.T. Conklin (jtc (at) wimsey.com), Winning Strategies, Inc. 52 */ 53 54 /* 55 * I've unrolled the loop eight times: large enough to make a 56 * significant difference, and small enough not to totally trash the 57 * cache. 58 */ 59 60 ENTRY(strncmp) 61 pushl %ebx 62 movl 8(%esp),%eax 63 movl 12(%esp),%ecx 64 movl 16(%esp),%edx 65 testl %edx,%edx 66 jmp L2 /* Jump into the loop! */ 67 68 .align 2,0x90 69 L1: incl %eax 70 incl %ecx 71 decl %edx 72 L2: je L4 /* strings are equal */ 73 movb (%eax),%bl 74 testb %bl,%bl 75 je L3 76 cmpb %bl,(%ecx) 77 jne L3 78 79 incl %eax 80 incl %ecx 81 decl %edx 82 je L4 83 movb (%eax),%bl 84 testb %bl,%bl 85 je L3 86 cmpb %bl,(%ecx) 87 jne L3 88 89 incl %eax 90 incl %ecx 91 decl %edx 92 je L4 93 movb (%eax),%bl 94 testb %bl,%bl 95 je L3 96 cmpb %bl,(%ecx) 97 jne L3 98 99 incl %eax 100 incl %ecx 101 decl %edx 102 je L4 103 movb (%eax),%bl 104 testb %bl,%bl 105 je L3 106 cmpb %bl,(%ecx) 107 jne L3 108 109 incl %eax 110 incl %ecx 111 decl %edx 112 je L4 113 movb (%eax),%bl 114 testb %bl,%bl 115 je L3 116 cmpb %bl,(%ecx) 117 jne L3 118 119 incl %eax 120 incl %ecx 121 decl %edx 122 je L4 123 movb (%eax),%bl 124 testb %bl,%bl 125 je L3 126 cmpb %bl,(%ecx) 127 jne L3 128 129 incl %eax 130 incl %ecx 131 decl %edx 132 je L4 133 movb (%eax),%bl 134 testb %bl,%bl 135 je L3 136 cmpb %bl,(%ecx) 137 jne L3 138 139 incl %eax 140 incl %ecx 141 decl %edx 142 je L4 143 movb (%eax),%bl 144 testb %bl,%bl 145 je L3 146 cmpb %bl,(%ecx) 147 je L1 148 149 .align 2,0x90 150 L3: movzbl (%eax),%eax /* unsigned comparision */ 151 movzbl (%ecx),%ecx 152 subl %ecx,%eax 153 popl %ebx 154 ret 155 .align 2,0x90 156 L4: xorl %eax,%eax 157 popl %ebx 158 ret 159
Indexes created Fri Sep 26 20:09:58 GMT 2025