src/sim/byteswap.hh

   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  */
  30
  31 //The purpose of this file is to provide endainness conversion utility
  32 //functions. Depending on the endianness of the guest system, either
  33 //the LittleEndianGuest or BigEndianGuest namespace is used.
  34
  35 #ifndef __SIM_BYTE_SWAP_HH__
  36 #define __SIM_BYTE_SWAP_HH__
  37
  38 #include "sim/host.hh"
  39
  40 // This lets us figure out what the byte order of the host system is
  41 #if defined(linux)
  42 #include <endian.h>
  43 // If this is a linux system, lets used the optimized definitions if they exist.
  44 // If one doesn't exist, we pretty much get what is listed below, so it all
  45 // works out
  46 #include <byteswap.h>
  47 #else
  48 #include <machine/endian.h>
  49 #endif
  50
  51 //These functions actually perform the swapping for parameters
  52 //of various bit lengths
  53 static inline uint64_t
  54 swap_byte64(uint64_t x)
  55 {
  56 #if defined(linux)
  57     return bswap_64(x);
  58 #else
  59     return  (uint64_t)((((uint64_t)(x) & 0xff) << 56) |
  60             ((uint64_t)(x) & 0xff00ULL) << 40 |
  61             ((uint64_t)(x) & 0xff0000ULL) << 24 |
  62             ((uint64_t)(x) & 0xff000000ULL) << 8 |
  63             ((uint64_t)(x) & 0xff00000000ULL) >> 8 |
  64             ((uint64_t)(x) & 0xff0000000000ULL) >> 24 |
  65             ((uint64_t)(x) & 0xff000000000000ULL) >> 40 |
  66             ((uint64_t)(x) & 0xff00000000000000ULL) >> 56) ;
  67 #endif
  68 }
  69
  70 static inline uint32_t
  71 swap_byte32(uint32_t x)
  72 {
  73 #if defined(linux)
  74     return bswap_32(x);
  75 #else
  76     return  (uint32_t)(((uint32_t)(x) & 0xff) << 24 |
  77             ((uint32_t)(x) & 0xff00) << 8 | ((uint32_t)(x) & 0xff0000) >> 8 |
  78             ((uint32_t)(x) & 0xff000000) >> 24);
  79 #endif
  80 }
  81
  82 static inline uint16_t
  83 swap_byte16(uint16_t x)
  84 {
  85 #if defined(linux)
  86     return bswap_16(x);
  87 #else
  88     return (uint16_t)(((uint16_t)(x) & 0xff) << 8 |
  89                       ((uint16_t)(x) & 0xff00) >> 8);
  90 #endif
  91 }
  92
  93 //This lets the compiler figure out how to call the swap_byte functions above
  94 //for different data types.
  95 static inline uint64_t swap_byte(uint64_t x) {return swap_byte64(x);}
  96 static inline int64_t swap_byte(int64_t x) {return swap_byte64((uint64_t)x);}
  97 static inline uint32_t swap_byte(uint32_t x) {return swap_byte32(x);}
  98 static inline int32_t swap_byte(int32_t x) {return swap_byte32((uint32_t)x);}
  99 //This is to prevent the following two functions from compiling on
 100 //64bit machines. It won't detect everything, so it should be changed.
 101 #ifndef __x86_64__
 102 static inline long swap_byte(long x) {return swap_byte32((long)x);}
 103 static inline unsigned long swap_byte(unsigned long x)
 104                                 { return swap_byte32((unsigned long)x);}
 105 #endif
 106 static inline uint16_t swap_byte(uint16_t x) {return swap_byte32(x);}
 107 static inline int16_t swap_byte(int16_t x) {return swap_byte16((uint16_t)x);}
 108 static inline uint8_t swap_byte(uint8_t x) {return x;}
 109 static inline int8_t swap_byte(int8_t x) {return x;}
 110 static inline double swap_byte(double x) {return swap_byte64((uint64_t)x);}
 111 static inline float swap_byte(float x) {return swap_byte32((uint32_t)x);}
 112
 113 //The conversion functions with fixed endianness on both ends don't need to
 114 //be in a namespace
 115 template <typename T> static inline T betole(T value) {return swap_byte(value);}
 116 template <typename T> static inline T letobe(T value) {return swap_byte(value);}
 117
 118 //For conversions not involving the guest system, we can define the functions
 119 //conditionally based on the BYTE_ORDER macro and outside of the namespaces
 120 #if BYTE_ORDER == BIG_ENDIAN
 121 template <typename T> static inline T htole(T value) {return swap_byte(value);}
 122 template <typename T> static inline T letoh(T value) {return swap_byte(value);}
 123 template <typename T> static inline T htobe(T value) {return value;}
 124 template <typename T> static inline T betoh(T value) {return value;}
 125 #elif BYTE_ORDER == LITTLE_ENDIAN
 126 template <typename T> static inline T htole(T value) {return value;}
 127 template <typename T> static inline T letoh(T value) {return value;}
 128 template <typename T> static inline T htobe(T value) {return swap_byte(value);}
 129 template <typename T> static inline T betoh(T value) {return swap_byte(value);}
 130 #else
 131         #error Invalid Endianess
 132 #endif
 133
 134 namespace BigEndianGuest
 135 {
 136         template <typename T>
 137         static inline T gtole(T value) {return betole(value);}
 138         template <typename T>
 139         static inline T letog(T value) {return letobe(value);}
 140         template <typename T>
 141         static inline T gtobe(T value) {return value;}
 142         template <typename T>
 143         static inline T betog(T value) {return value;}
 144         template <typename T>
 145         static inline T htog(T value) {return htobe(value);}
 146         template <typename T>
 147         static inline T gtoh(T value) {return betoh(value);}
 148 }
 149
 150 namespace LittleEndianGuest
 151 {
 152         template <typename T>
 153         static inline T gtole(T value) {return value;}
 154         template <typename T>
 155         static inline T letog(T value) {return value;}
 156         template <typename T>
 157         static inline T gtobe(T value) {return letobe(value);}
 158         template <typename T>
 159         static inline T betog(T value) {return betole(value);}
 160         template <typename T>
 161         static inline T htog(T value) {return htole(value);}
 162         template <typename T>
 163         static inline T gtoh(T value) {return letoh(value);}
 164 }
 165 #endif // __SIM_BYTE_SWAP_HH__