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  *          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
  61 inline uint64_t
  62 swap_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
  80 inline uint32_t
  81 swap_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
  94 inline uint16_t
  95 swap_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.
 111 template <typename T>
 112 inline 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
 125 template <typename T, size_t N>
 126 inline std::array<T, N>
 127 swap_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
 136 template <typename T> inline T betole(T value) {return swap_byte(value);}
 137 template <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
 142 const ByteOrder HostByteOrder = BigEndianByteOrder;
 143 template <typename T> inline T htole(T value) {return swap_byte(value);}
 144 template <typename T> inline T letoh(T value) {return swap_byte(value);}
 145 template <typename T> inline T htobe(T value) {return value;}
 146 template <typename T> inline T betoh(T value) {return value;}
 147 #elif defined(_LITTLE_ENDIAN) || BYTE_ORDER == LITTLE_ENDIAN
 148 const ByteOrder HostByteOrder = LittleEndianByteOrder;
 149 template <typename T> inline T htole(T value) {return value;}
 150 template <typename T> inline T letoh(T value) {return value;}
 151 template <typename T> inline T htobe(T value) {return swap_byte(value);}
 152 template <typename T> inline T betoh(T value) {return swap_byte(value);}
 153 #else
 154         #error Invalid Endianess
 155 #endif
 156
 157 namespace 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
 174 namespace 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__