projects / apple / xnu.git / blame
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|---|---|---|
| 1c79356b A |
1 | /* |
| 2 | * Copyright (c) 2000 Apple Computer, Inc. All rights reserved. | |
| 3 | * | |
| 4 | * @APPLE_LICENSE_HEADER_START@ | |
| 5 | * | |
| e5568f75 A |
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. | |
| 1c79356b | 11 | * |
| e5568f75 A |
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 | |
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14 | * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, |
| 15 | * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, | |
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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. | |
| 1c79356b A |
19 | * |
| 20 | * @APPLE_LICENSE_HEADER_END@ | |
| 21 | */ | |
| 22 | /* Copyright (c) 1992, 1997-1998 Apple Computer, Inc. All rights reserved. | |
| 23 | * | |
| 24 | * File: machdep/ppc/libc/ffs.s | |
| 25 | * | |
| 26 | * int ffs(int value) | |
| 27 | * | |
| 28 | * DESCRIPTION | |
| 29 | * The ffs() function finds the first bit set in value and returns the | |
| 30 | * index of that bit. Bits are numbered starting from 1, starting at | |
| 31 | * the right-most bit. A return value of 0 means that the argument was | |
| 32 | * | |
| 33 | * HISTORY | |
| 34 | * 14-Aug-1998 Umesh Vaishampayan (umeshv@apple.com) | |
| 35 | * Optimized! | |
| 36 | * | |
| 37 | * 10-Mar-1998 Matt Watson (mwatson@apple.com) | |
| 38 | * Correctified | |
| 39 | * | |
| 40 | * 19-Jan-1998 Matt Watson (mwatson@apple.com) | |
| 41 | * Simplified | |
| 42 | * | |
| 43 | * 24-Jan-1997 Umesh Vaishampayan (umeshv@NeXT.com) | |
| 44 | * Ported to PPC. | |
| 45 | */ | |
| 46 | ||
| 47 | .text | |
| 48 | .align 4 | |
| 49 | .globl _ffs | |
| 50 | _ffs: /* Cycles */ | |
| 51 | neg r0,r3 /* 0 */ | |
| 52 | and r3,r0,r3 /* 1 */ | |
| 53 | li r4, 32 /* 1 */ | |
| 54 | cntlzw r3,r3 /* 2 */ | |
| 55 | subf r3,r3,r4 /* 3 */ | |
| 56 | blr | |
| 57 | ||
| 58 | .globl _abs | |
| 59 | _abs: | |
| 60 | srawi r0,r3,31 | |
| 61 | xor r3,r0,r3 | |
| 62 | subf r3,r0,r3 | |
| 63 | blr | |
| 64 |