1/* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License, Version 1.0 only 6 * (the "License"). You may not use this file except in compliance 7 * with the License. 8 * 9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 10 * or http://www.opensolaris.org/os/licensing. 11 * See the License for the specific language governing permissions 12 * and limitations under the License. 13 * 14 * When distributing Covered Code, include this CDDL HEADER in each 15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 16 * If applicable, add the following below this CDDL HEADER, with the 17 * fields enclosed by brackets "[]" replaced with your own identifying 18 * information: Portions Copyright [yyyy] [name of copyright owner] 19 * 20 * CDDL HEADER END 21 */ 22/* 23 * Copyright 2004 Sun Microsystems, Inc. All rights reserved. 24 * Use is subject to license terms. 25 */ 26 27 .ident "%Z%%M% %I% %E% SMI" 28 29 .file "%M%" 30 31/ 32/ strrchr(sp, c) 33/ 34/ Returns the pointer in sp at which the character c last 35/ appears; NULL if no found 36/ 37/ Fast assembly language version of the following C-program strrchr 38/ which represents the `standard' for the C-library. 39/ 40/ char * 41/ strrchr(const char *sp, int c) 42/ { 43/ char *r = NULL; 44/ 45/ do { 46/ if (*sp == (char)c) 47/ r = (char *)sp; 48/ } while (*sp++); 49/ 50/ return (r); 51/ } 52/ 53 54#include "SYS.h" 55 56 ENTRY(strrchr) 57 pushl %edi / save register variable 58 movl 8(%esp), %eax / %eax = string address 59 movb 12(%esp), %cl / %cl = char sought 60 movl $0, %edi / %edi = NULL (current occurrence) 61 62 testl $3, %eax / if %eax not word aligned 63 jnz .L1 / goto .L1 64 .align 4 65.L3: 66 movl (%eax), %edx / move 1 word from (%eax) to %edx 67 cmpb %cl, %dl / if the fist byte is not %cl 68 jne .L4 / goto .L4 69 movl %eax, %edi / save this address to %edi 70.L4: 71 cmpb $0, %dl / if a null termination 72 je .L8 / goto .L8 73 74 cmpb %cl, %dh / if the second byte is not %cl 75 jne .L5 / goto .L5 76 leal 1(%eax), %edi / save this address to %edi 77.L5: 78 cmpb $0, %dh / if a null termination 79 je .L8 / goto .L8 80 81 shrl $16, %edx / right shift 16-bit 82 cmpb %cl, %dl / if the third byte is not %cl 83 jne .L6 / goto .L6 84 leal 2(%eax), %edi / save this address to %edi 85.L6: 86 cmpb $0, %dl / if a null termination 87 je .L8 / goto .L8 88 89 cmpb %cl, %dh / if the fourth byte is not %cl 90 jne .L7 / goto .L7 91 leal 3(%eax), %edi / save this address to %edi 92.L7: 93 cmpb $0, %dh / if a null termination 94 je .L8 / goto .L8 95 96 addl $4, %eax / next word 97 jmp .L3 / goto .L3 98 .align 4 99.L1: 100 movb (%eax), %dl / move 1 byte from (%eax) to %dl 101 cmpb %cl, %dl / if %dl is not %cl 102 jne .L2 / goto .L2 103 movl %eax, %edi / save this address to %edi 104.L2: 105 cmpb $0, %dl / if a null termination 106 je .L8 / goto .L8 107 108 incl %eax / next byte 109 testl $3, %eax / if %eax not word aligned 110 jnz .L1 / goto .L1 111 jmp .L3 / goto .L3 (word aligned) 112 .align 4 113.L8: 114 movl %edi, %eax / %edi points to the last occurrence or NULL 115 popl %edi / restore register variable 116 ret 117 SET_SIZE(strrchr) 118