1/* 2 * Copyright (c) 2000 Apple Computer, Inc. All rights reserved. 3 * 4 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@ 5 * 6 * This file contains Original Code and/or Modifications of Original Code 7 * as defined in and that are subject to the Apple Public Source License 8 * Version 2.0 (the 'License'). You may not use this file except in 9 * compliance with the License. The rights granted to you under the License 10 * may not be used to create, or enable the creation or redistribution of, 11 * unlawful or unlicensed copies of an Apple operating system, or to 12 * circumvent, violate, or enable the circumvention or violation of, any 13 * terms of an Apple operating system software license agreement. 14 * 15 * Please obtain a copy of the License at 16 * http://www.opensource.apple.com/apsl/ and read it before using this file. 17 * 18 * The Original Code and all software distributed under the License are 19 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER 20 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, 21 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, 22 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. 23 * Please see the License for the specific language governing rights and 24 * limitations under the License. 25 * 26 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ 27 */ 28/* Copyright (c) 1992, 1997-1998 Apple Computer, Inc. All rights reserved. 29 * 30 * File: machdep/ppc/libc/ffs.s 31 * 32 * int ffs(int value) 33 * 34 * DESCRIPTION 35 * The ffs() function finds the first bit set in value and returns the 36 * index of that bit. Bits are numbered starting from 1, starting at 37 * the right-most bit. A return value of 0 means that the argument was 38 * 39 * HISTORY 40 * 14-Aug-1998 Umesh Vaishampayan (umeshv@apple.com) 41 * Optimized! 42 * 43 * 10-Mar-1998 Matt Watson (mwatson@apple.com) 44 * Correctified 45 * 46 * 19-Jan-1998 Matt Watson (mwatson@apple.com) 47 * Simplified 48 * 49 * 24-Jan-1997 Umesh Vaishampayan (umeshv@NeXT.com) 50 * Ported to PPC. 51 */ 52 53.text 54.align 4 55.globl _ffs 56_ffs: /* Cycles */ 57 neg r0,r3 /* 0 */ 58 and r3,r0,r3 /* 1 */ 59 li r4, 32 /* 1 */ 60 cntlzw r3,r3 /* 2 */ 61 subf r3,r3,r4 /* 3 */ 62 blr 63 64 .globl _abs 65_abs: 66 srawi r0,r3,31 67 xor r3,r0,r3 68 subf r3,r0,r3 69 blr 70 71