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/bigint.hh"
  41 #include "base/misc.hh"
  42 #include "base/types.hh"
  43
  44 // This lets us figure out what the byte order of the host system is
  45 #if defined(__linux__)
  46 #include <endian.h>
  47 // If this is a linux system, lets used the optimized definitions if they exist.
  48 // If one doesn't exist, we pretty much get what is listed below, so it all
  49 // works out
  50 #include <byteswap.h>
  51 #elif defined (__sun)
  52 #include <sys/isa_defs.h>
  53 #else
  54 #include <machine/endian.h>
  55 #endif
  56
  57 #if defined(__APPLE__)
  58 #include <libkern/OSByteOrder.h>
  59 #endif
  60
  61 enum ByteOrder {BigEndianByteOrder, LittleEndianByteOrder};
  62
  63 //These functions actually perform the swapping for parameters
  64 //of various bit lengths
  65 inline uint64_t
  66 swap_byte64(uint64_t x)
  67 {
  68 #if defined(__linux__)
  69     return bswap_64(x);
  70 #elif defined(__APPLE__)
  71     return OSSwapInt64(x);
  72 #else
  73     return  (uint64_t)((((uint64_t)(x) & 0xff) << 56) |
  74             ((uint64_t)(x) & 0xff00ULL) << 40 |
  75             ((uint64_t)(x) & 0xff0000ULL) << 24 |
  76             ((uint64_t)(x) & 0xff000000ULL) << 8 |
  77             ((uint64_t)(x) & 0xff00000000ULL) >> 8 |
  78             ((uint64_t)(x) & 0xff0000000000ULL) >> 24 |
  79             ((uint64_t)(x) & 0xff000000000000ULL) >> 40 |
  80             ((uint64_t)(x) & 0xff00000000000000ULL) >> 56) ;
  81 #endif
  82 }
  83
  84 inline uint32_t
  85 swap_byte32(uint32_t x)
  86 {
  87 #if defined(__linux__)
  88     return bswap_32(x);
  89 #elif defined(__APPLE__)
  90     return OSSwapInt32(x);
  91 #else
  92     return  (uint32_t)(((uint32_t)(x) & 0xff) << 24 |
  93             ((uint32_t)(x) & 0xff00) << 8 | ((uint32_t)(x) & 0xff0000) >> 8 |
  94             ((uint32_t)(x) & 0xff000000) >> 24);
  95 #endif
  96 }
  97
  98 inline uint16_t
  99 swap_byte16(uint16_t x)
 100 {
 101 #if defined(__linux__)
 102     return bswap_16(x);
 103 #elif defined(__APPLE__)
 104     return OSSwapInt16(x);
 105 #else
 106     return (uint16_t)(((uint16_t)(x) & 0xff) << 8 |
 107                       ((uint16_t)(x) & 0xff00) >> 8);
 108 #endif
 109 }
 110
 111 // This function lets the compiler figure out how to call the
 112 // swap_byte functions above for different data types.  Since the
 113 // sizeof() values are known at compile time, it should inline to a
 114 // direct call to the right swap_byteNN() function.
 115 template <typename T>
 116 inline T swap_byte(T x) {
 117     if (sizeof(T) == 8)
 118         return swap_byte64((uint64_t)x);
 119     else if (sizeof(T) == 4)
 120         return swap_byte32((uint32_t)x);
 121     else if (sizeof(T) == 2)
 122         return swap_byte16((uint16_t)x);
 123     else if (sizeof(T) == 1)
 124         return x;
 125     else
 126         panic("Can't byte-swap values larger than 64 bits");
 127 }
 128
 129 template<>
 130 inline Twin64_t swap_byte<Twin64_t>(Twin64_t x)
 131 {
 132     x.a = swap_byte(x.a);
 133     x.b = swap_byte(x.b);
 134     return x;
 135 }
 136
 137 template<>
 138 inline Twin32_t swap_byte<Twin32_t>(Twin32_t x)
 139 {
 140     x.a = swap_byte(x.a);
 141     x.b = swap_byte(x.b);
 142     return x;
 143 }
 144
 145 //The conversion functions with fixed endianness on both ends don't need to
 146 //be in a namespace
 147 template <typename T> inline T betole(T value) {return swap_byte(value);}
 148 template <typename T> inline T letobe(T value) {return swap_byte(value);}
 149
 150 //For conversions not involving the guest system, we can define the functions
 151 //conditionally based on the BYTE_ORDER macro and outside of the namespaces
 152 #if defined(_BIG_ENDIAN) || !defined(_LITTLE_ENDIAN) && BYTE_ORDER == BIG_ENDIAN
 153 const ByteOrder HostByteOrder = BigEndianByteOrder;
 154 template <typename T> inline T htole(T value) {return swap_byte(value);}
 155 template <typename T> inline T letoh(T value) {return swap_byte(value);}
 156 template <typename T> inline T htobe(T value) {return value;}
 157 template <typename T> inline T betoh(T value) {return value;}
 158 #elif defined(_LITTLE_ENDIAN) || BYTE_ORDER == LITTLE_ENDIAN
 159 const ByteOrder HostByteOrder = LittleEndianByteOrder;
 160 template <typename T> inline T htole(T value) {return value;}
 161 template <typename T> inline T letoh(T value) {return value;}
 162 template <typename T> inline T htobe(T value) {return swap_byte(value);}
 163 template <typename T> inline T betoh(T value) {return swap_byte(value);}
 164 #else
 165         #error Invalid Endianess
 166 #endif
 167
 168 namespace BigEndianGuest
 169 {
 170     const ByteOrder GuestByteOrder = BigEndianByteOrder;
 171     template <typename T>
 172     inline T gtole(T value) {return betole(value);}
 173     template <typename T>
 174     inline T letog(T value) {return letobe(value);}
 175     template <typename T>
 176     inline T gtobe(T value) {return value;}
 177     template <typename T>
 178     inline T betog(T value) {return value;}
 179     template <typename T>
 180     inline T htog(T value) {return htobe(value);}
 181     template <typename T>
 182     inline T gtoh(T value) {return betoh(value);}
 183 }
 184
 185 namespace LittleEndianGuest
 186 {
 187     const ByteOrder GuestByteOrder = LittleEndianByteOrder;
 188     template <typename T>
 189     inline T gtole(T value) {return value;}
 190     template <typename T>
 191     inline T letog(T value) {return value;}
 192     template <typename T>
 193     inline T gtobe(T value) {return letobe(value);}
 194     template <typename T>
 195     inline T betog(T value) {return betole(value);}
 196     template <typename T>
 197     inline T htog(T value) {return htole(value);}
 198     template <typename T>
 199     inline T gtoh(T value) {return letoh(value);}
 200 }
 201 #endif // __SIM_BYTE_SWAP_HH__