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) /* (char *s, int c) */ 57 movl $0, %eax / %rax = NULL (current occurrence) 58 movl %esi, %ecx / %cl == char to search for 59 testq $3, %rdi / if %rdi not word aligned 60 jnz .L1 / goto .L1 61 .align 4 62.L3: 63 movl (%rdi), %edx / move 1 word from (%rdi) to %edx 64 cmpb %cl, %dl / if the fist byte is not %cl 65 jne .L4 / goto .L4 66 movq %rdi, %rax / save this address to %rax 67.L4: 68 cmpb $0, %dl / if a null termination 69 je .L8 / goto .L8 70 71 cmpb %cl, %dh / if the second byte is not %cl 72 jne .L5 / goto .L5 73 leaq 1(%rdi), %rax / save this address to %rax 74.L5: 75 cmpb $0, %dh / if a null termination 76 je .L8 / goto .L8 77 78 shrl $16, %edx / right shift 16-bit 79 cmpb %cl, %dl / if the third byte is not %cl 80 jne .L6 / goto .L6 81 leaq 2(%rdi), %rax / save this address to %rax 82.L6: 83 cmpb $0, %dl / if a null termination 84 je .L8 / goto .L8 85 86 cmpb %cl, %dh / if the fourth byte is not %cl 87 jne .L7 / goto .L7 88 leaq 3(%rdi), %rax / save this address to %rax 89.L7: 90 cmpb $0, %dh / if a null termination 91 je .L8 / goto .L8 92 93 addq $4, %rdi / next word 94 jmp .L3 / goto .L3 95 .align 4 96.L1: 97 movb (%rdi), %dl / move 1 byte from (%rdi) to %dl 98 cmpb %cl, %dl / if %dl is not %cl 99 jne .L2 / goto .L2 100 movq %rdi, %rax / save this address to %rax 101.L2: 102 cmpb $0, %dl / if a null termination 103 je .L8 / goto .L8 104 105 incq %rdi / next byte 106 testq $3, %rdi / if %rdi not word aligned 107 jnz .L1 / goto .L1 108 jmp .L3 / goto .L3 (word aligned) 109 .align 4 110.L8: 111 ret / %rax points to the last occurrence or NULL 112 SET_SIZE(strrchr) 113