1/* 2 * Copyright (c) 2000 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, 1997-1998 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 65