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