1/* 2 * Copyright (c) 2003-2005 The Regents of The University of Michigan 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions are 7 * met: redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer; 9 * redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution; 12 * neither the name of the copyright holders nor the names of its 13 * contributors may be used to endorse or promote products derived from 14 * this software without specific prior written permission. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 17 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 18 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 19 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 20 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 21 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 22 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 26 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 * 28 * Authors: Steve Reinhardt 29 * Nathan Binkert 30 */ 31 32#ifndef __BASE_BITFIELD_HH__ 33#define __BASE_BITFIELD_HH__ 34 35#include <inttypes.h> 36 37/** 38 * Generate a 64-bit mask of 'nbits' 1s, right justified. 39 */ 40inline uint64_t 41mask(int nbits) 42{ 43 return (nbits == 64) ? (uint64_t)-1LL : (1ULL << nbits) - 1; 44} 45 46 47/** 48 * Extract the bitfield from position 'first' to 'last' (inclusive) 49 * from 'val' and right justify it. MSB is numbered 63, LSB is 0. 50 */ 51template <class T> 52inline 53T 54bits(T val, int first, int last) 55{ 56 int nbits = first - last + 1; 57 return (val >> last) & mask(nbits); 58} 59 60/** 61 * Sign-extend an N-bit value to 64 bits. 62 */ 63template <int N> 64inline 65int64_t 66sext(uint64_t val) 67{ 68 int sign_bit = bits(val, N-1, N-1); 69 return sign_bit ? (val | ~mask(N)) : val; 70} 71
| 1/* 2 * Copyright (c) 2003-2005 The Regents of The University of Michigan 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions are 7 * met: redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer; 9 * redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution; 12 * neither the name of the copyright holders nor the names of its 13 * contributors may be used to endorse or promote products derived from 14 * this software without specific prior written permission. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 17 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 18 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 19 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 20 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 21 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 22 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 26 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 * 28 * Authors: Steve Reinhardt 29 * Nathan Binkert 30 */ 31 32#ifndef __BASE_BITFIELD_HH__ 33#define __BASE_BITFIELD_HH__ 34 35#include <inttypes.h> 36 37/** 38 * Generate a 64-bit mask of 'nbits' 1s, right justified. 39 */ 40inline uint64_t 41mask(int nbits) 42{ 43 return (nbits == 64) ? (uint64_t)-1LL : (1ULL << nbits) - 1; 44} 45 46 47/** 48 * Extract the bitfield from position 'first' to 'last' (inclusive) 49 * from 'val' and right justify it. MSB is numbered 63, LSB is 0. 50 */ 51template <class T> 52inline 53T 54bits(T val, int first, int last) 55{ 56 int nbits = first - last + 1; 57 return (val >> last) & mask(nbits); 58} 59 60/** 61 * Sign-extend an N-bit value to 64 bits. 62 */ 63template <int N> 64inline 65int64_t 66sext(uint64_t val) 67{ 68 int sign_bit = bits(val, N-1, N-1); 69 return sign_bit ? (val | ~mask(N)) : val; 70} 71
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| 72/** 73 * Return val with bits first to last set to bit_val 74 */ 75template <class T, class B> 76inline 77T 78insertBits(T val, int first, int last, B bit_val) 79{ 80 T bmask = mask(first - last + 1) << last; 81 return ((bit_val << last) & bmask) | (val & ~bmask); 82} 83 84/** 85 * A convenience function to replace bits first to last of val with bit_val 86 * in place. 87 */ 88template <class T, class B> 89inline 90void 91replaceBits(T& val, int first, int last, B bit_val) 92{ 93 val = insertBits(val, first, last, bit_val); 94} 95
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