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