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 (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 22 /* 23 * Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved. 24 */ 25 26 #include "lint.h" 27 #include <string.h> 28 #include <strings.h> 29 #include <sys/types.h> 30 31 static int fls_impl(uint64_t bits)32fls_impl(uint64_t bits) 33 { 34 int i = 1; 35 uint32_t bits32; 36 37 if (bits == 0) 38 return (0); 39 40 if ((bits32 = (uint32_t)(bits >> 32)) != 0) 41 i += 32; 42 else 43 bits32 = (uint32_t)bits; 44 45 if ((bits32 & 0xffff0000) != 0) { 46 bits32 >>= 16; 47 i += 16; 48 } 49 if ((bits32 & 0xff00) != 0) { 50 bits32 >>= 8; 51 i += 8; 52 } 53 if ((bits32 & 0xf0) != 0) { 54 bits32 >>= 4; 55 i += 4; 56 } 57 if ((bits32 & 0xc) != 0) { 58 bits32 >>= 2; 59 i += 2; 60 } 61 if ((bits32 & 0x2) != 0) 62 i += 1; 63 64 return (i); 65 } 66 67 int fls(int bits)68fls(int bits) 69 { 70 return (fls_impl((uint64_t)(uint_t)bits)); 71 } 72 73 int flsl(long bits)74flsl(long bits) 75 { 76 return (fls_impl((uint64_t)(ulong_t)bits)); 77 } 78 79 int flsll(long long bits)80flsll(long long bits) 81 { 82 return (fls_impl((uint64_t)(u_longlong_t)bits)); 83 } 84