projects / apple / libc.git / blame
| Commit | Line | Data |
|---|---|---|
| e9ce8d39 A |
1 | /* |
| 2 | * Copyright (c) 1999 Apple Computer, Inc. All rights reserved. | |
| 3 | * | |
| 4 | * @APPLE_LICENSE_HEADER_START@ | |
| 5 | * | |
| 6 | * The contents of this file constitute Original Code as defined in and | |
| 7 | * are subject to the Apple Public Source License Version 1.1 (the | |
| 8 | * "License"). You may not use this file except in compliance with the | |
| 9 | * License. Please obtain a copy of the License at | |
| 10 | * http://www.apple.com/publicsource and read it before using this file. | |
| 11 | * | |
| 12 | * This Original Code and all software distributed under the License are | |
| 13 | * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER | |
| 14 | * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, | |
| 15 | * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, | |
| 16 | * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the | |
| 17 | * License for the specific language governing rights and limitations | |
| 18 | * under the License. | |
| 19 | * | |
| 20 | * @APPLE_LICENSE_HEADER_END@ | |
| 21 | */ | |
| 22 | /* Copyright (c) 1992, 1997 NeXT Software, Inc. All rights reserved. | |
| 23 | * | |
| 24 | * File: libc/gen/ppc/strlen.s | |
| 25 | * | |
| 26 | * HISTORY | |
| 27 | * 24-Jan-1997 Umesh Vaishampayan (umeshv@NeXT.com) | |
| 28 | * Ported to PPC. | |
| 29 | * 12-Nov-92 Derek B Clegg (dclegg@next.com) | |
| 30 | * Created. | |
| 31 | * | |
| 32 | * size_t strlen(const char *s); | |
| 33 | * | |
| 34 | * Description: | |
| 35 | * | |
| 36 | * Returns: | |
| 37 | */ | |
| 38 | #import <architecture/ppc/asm_help.h> | |
| 39 | #import <architecture/ppc/pseudo_inst.h> | |
| 40 | ||
| 41 | /* size_t strlen(const char *s); */ | |
| 42 | ||
| 43 | #define a8 ep | |
| 44 | #define a9 at | |
| 45 | ||
| 46 | .at_off | |
| 47 | ||
| 48 | #define check_for_zero(reg, tmp, found_zero, checked_all) \ | |
| 49 | extrwi. tmp,reg,8,0 @\ | |
| 50 | beq- found_zero @\ | |
| 51 | bdz- checked_all @\ | |
| 52 | extrwi. tmp,reg,8,8 @\ | |
| 53 | beq- found_zero @\ | |
| 54 | bdz- checked_all @\ | |
| 55 | extrwi. tmp,reg,8,16 @\ | |
| 56 | beq- found_zero @\ | |
| 57 | bdz- checked_all @\ | |
| 58 | extrwi. tmp,reg,8,24 @\ | |
| 59 | beq- found_zero @\ | |
| 60 | bdz- checked_all | |
| 61 | ||
| 62 | #define check_32(tmp, found_zero) \ | |
| 63 | check_for_zero(a2, tmp, found_zero, 1f) @\ | |
| 64 | check_for_zero(a3, tmp, found_zero, 1f) @\ | |
| 65 | check_for_zero(a4, tmp, found_zero, 1f) @\ | |
| 66 | check_for_zero(a5, tmp, found_zero, 1f) @\ | |
| 67 | check_for_zero(a6, tmp, found_zero, 1f) @\ | |
| 68 | check_for_zero(a7, tmp, found_zero, 1f) @\ | |
| 69 | check_for_zero(a8, tmp, found_zero, 1f) @\ | |
| 70 | check_for_zero(a9, tmp, found_zero, 1f) @\ | |
| 71 | 1: | |
| 72 | ||
| 73 | LEAF(_strlen) | |
| 74 | dcbt 0,a0 // Try to load the cache line. | |
| 75 | andi. a1,a0,31 // We want to be 32-byte aligned. | |
| 76 | subfic a1,a1,32 // Get the number of bytes to start with. | |
| 77 | mtxer a1 // Setup xer for load. | |
| 78 | lswx a2,0,a0 // Load the bytes. | |
| 79 | mtctr a1 // Setup ctr for zero check. | |
| 80 | check_32(zt, L_found_zero) | |
| 81 | ||
| 82 | /* Now check 32-byte blocks. At this point, ctr is zero, so we can | |
| 83 | * use it as our running count. */ | |
| 84 | dcbt a1,a0 // Try to load the cache line. | |
| 85 | li32 a2,32 | |
| 86 | mtxer a2 | |
| 87 | li32 a2,0 | |
| 88 | mtctr a2 | |
| 89 | ||
| 90 | 2: lswx a2,a1,a0 // Load 32 bytes. | |
| 91 | check_32(zt, L_found_zero) | |
| 92 | addi a0,a0,32 // Increment the pointer. | |
| 93 | dcbt a1,a0 // Try to load the cache. | |
| 94 | b 2b // Loop | |
| 95 | ||
| 96 | L_found_zero: | |
| 97 | mfctr a0 | |
| 98 | sub a0,a1,a0 // Get the number of bytes before 0. | |
| 99 | blr // Return. | |
| 100 | END(_strlen) |