byteswap.hh revision 12386:2bf5fb25a5f1
1/* 2 * Copyright (c) 2004 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: Gabe Black 29 * Ali Saidi 30 * Nathan Binkert 31 */ 32 33//The purpose of this file is to provide endainness conversion utility 34//functions. Depending on the endianness of the guest system, either 35//the LittleEndianGuest or BigEndianGuest namespace is used. 36 37#ifndef __SIM_BYTE_SWAP_HH__ 38#define __SIM_BYTE_SWAP_HH__ 39 40#include "base/types.hh" 41 42// This lets us figure out what the byte order of the host system is 43#if defined(__linux__) 44#include <endian.h> 45// If this is a linux system, lets used the optimized definitions if they exist. 46// If one doesn't exist, we pretty much get what is listed below, so it all 47// works out 48#include <byteswap.h> 49#elif defined (__sun) 50#include <sys/isa_defs.h> 51#else 52#include <machine/endian.h> 53#endif 54 55#if defined(__APPLE__) 56#include <libkern/OSByteOrder.h> 57#endif 58 59//These functions actually perform the swapping for parameters 60//of various bit lengths 61inline uint64_t 62swap_byte64(uint64_t x) 63{ 64#if defined(__linux__) 65 return bswap_64(x); 66#elif defined(__APPLE__) 67 return OSSwapInt64(x); 68#else 69 return (uint64_t)((((uint64_t)(x) & 0xff) << 56) | 70 ((uint64_t)(x) & 0xff00ULL) << 40 | 71 ((uint64_t)(x) & 0xff0000ULL) << 24 | 72 ((uint64_t)(x) & 0xff000000ULL) << 8 | 73 ((uint64_t)(x) & 0xff00000000ULL) >> 8 | 74 ((uint64_t)(x) & 0xff0000000000ULL) >> 24 | 75 ((uint64_t)(x) & 0xff000000000000ULL) >> 40 | 76 ((uint64_t)(x) & 0xff00000000000000ULL) >> 56) ; 77#endif 78} 79 80inline uint32_t 81swap_byte32(uint32_t x) 82{ 83#if defined(__linux__) 84 return bswap_32(x); 85#elif defined(__APPLE__) 86 return OSSwapInt32(x); 87#else 88 return (uint32_t)(((uint32_t)(x) & 0xff) << 24 | 89 ((uint32_t)(x) & 0xff00) << 8 | ((uint32_t)(x) & 0xff0000) >> 8 | 90 ((uint32_t)(x) & 0xff000000) >> 24); 91#endif 92} 93 94inline uint16_t 95swap_byte16(uint16_t x) 96{ 97#if defined(__linux__) 98 return bswap_16(x); 99#elif defined(__APPLE__) 100 return OSSwapInt16(x); 101#else 102 return (uint16_t)(((uint16_t)(x) & 0xff) << 8 | 103 ((uint16_t)(x) & 0xff00) >> 8); 104#endif 105} 106 107// This function lets the compiler figure out how to call the 108// swap_byte functions above for different data types. Since the 109// sizeof() values are known at compile time, it should inline to a 110// direct call to the right swap_byteNN() function. 111template <typename T> 112inline T swap_byte(T x) { 113 if (sizeof(T) == 8) 114 return swap_byte64((uint64_t)x); 115 else if (sizeof(T) == 4) 116 return swap_byte32((uint32_t)x); 117 else if (sizeof(T) == 2) 118 return swap_byte16((uint16_t)x); 119 else if (sizeof(T) == 1) 120 return x; 121 else 122 panic("Can't byte-swap values larger than 64 bits"); 123} 124 125template <typename T, size_t N> 126inline std::array<T, N> 127swap_byte(std::array<T, N> a) 128{ 129 for (T &v: a) 130 v = swap_byte(v); 131 return a; 132} 133 134//The conversion functions with fixed endianness on both ends don't need to 135//be in a namespace 136template <typename T> inline T betole(T value) {return swap_byte(value);} 137template <typename T> inline T letobe(T value) {return swap_byte(value);} 138 139//For conversions not involving the guest system, we can define the functions 140//conditionally based on the BYTE_ORDER macro and outside of the namespaces 141#if (defined(_BIG_ENDIAN) || !defined(_LITTLE_ENDIAN)) && BYTE_ORDER == BIG_ENDIAN 142const ByteOrder HostByteOrder = BigEndianByteOrder; 143template <typename T> inline T htole(T value) {return swap_byte(value);} 144template <typename T> inline T letoh(T value) {return swap_byte(value);} 145template <typename T> inline T htobe(T value) {return value;} 146template <typename T> inline T betoh(T value) {return value;} 147#elif defined(_LITTLE_ENDIAN) || BYTE_ORDER == LITTLE_ENDIAN 148const ByteOrder HostByteOrder = LittleEndianByteOrder; 149template <typename T> inline T htole(T value) {return value;} 150template <typename T> inline T letoh(T value) {return value;} 151template <typename T> inline T htobe(T value) {return swap_byte(value);} 152template <typename T> inline T betoh(T value) {return swap_byte(value);} 153#else 154 #error Invalid Endianess 155#endif 156 157namespace BigEndianGuest 158{ 159 const ByteOrder GuestByteOrder = BigEndianByteOrder; 160 template <typename T> 161 inline T gtole(T value) {return betole(value);} 162 template <typename T> 163 inline T letog(T value) {return letobe(value);} 164 template <typename T> 165 inline T gtobe(T value) {return value;} 166 template <typename T> 167 inline T betog(T value) {return value;} 168 template <typename T> 169 inline T htog(T value) {return htobe(value);} 170 template <typename T> 171 inline T gtoh(T value) {return betoh(value);} 172} 173 174namespace LittleEndianGuest 175{ 176 const ByteOrder GuestByteOrder = LittleEndianByteOrder; 177 template <typename T> 178 inline T gtole(T value) {return value;} 179 template <typename T> 180 inline T letog(T value) {return value;} 181 template <typename T> 182 inline T gtobe(T value) {return letobe(value);} 183 template <typename T> 184 inline T betog(T value) {return betole(value);} 185 template <typename T> 186 inline T htog(T value) {return htole(value);} 187 template <typename T> 188 inline T gtoh(T value) {return letoh(value);} 189} 190#endif // __SIM_BYTE_SWAP_HH__ 191