byteswap.hh revision 2764 
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
53static inline uint64_t
54swap_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
70static inline uint32_t
71swap_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
82static inline uint16_t
83swap_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 function lets the compiler figure out how to call the
94// swap_byte functions above for different data types.  Since the
95// sizeof() values are known at compiel time, it should inline to a
96// direct call to the right swap_byteNN() function.
97template <typename T>
98static inline T swap_byte(T x) {
99    if (sizeof(T) == 8)
100        return swap_byte64((uint64_t)x);
101    else if (sizeof(T) == 4)
102        return swap_byte32((uint32_t)x);
103    else if (sizeof(T) == 2)
104        return swap_byte16((uint16_t)x);
105    else if (sizeof(T) == 1)
106        return x;
107    else
108        panic("Can't byte-swap values larger than 64 bits");
109}
110
111//The conversion functions with fixed endianness on both ends don't need to
112//be in a namespace
113template <typename T> static inline T betole(T value) {return swap_byte(value);}
114template <typename T> static inline T letobe(T value) {return swap_byte(value);}
115
116//For conversions not involving the guest system, we can define the functions
117//conditionally based on the BYTE_ORDER macro and outside of the namespaces
118#if BYTE_ORDER == BIG_ENDIAN
119template <typename T> static inline T htole(T value) {return swap_byte(value);}
120template <typename T> static inline T letoh(T value) {return swap_byte(value);}
121template <typename T> static inline T htobe(T value) {return value;}
122template <typename T> static inline T betoh(T value) {return value;}
123#elif BYTE_ORDER == LITTLE_ENDIAN
124template <typename T> static inline T htole(T value) {return value;}
125template <typename T> static inline T letoh(T value) {return value;}
126template <typename T> static inline T htobe(T value) {return swap_byte(value);}
127template <typename T> static inline T betoh(T value) {return swap_byte(value);}
128#else
129        #error Invalid Endianess
130#endif
131
132namespace BigEndianGuest
133{
134        template <typename T>
135        static inline T gtole(T value) {return betole(value);}
136        template <typename T>
137        static inline T letog(T value) {return letobe(value);}
138        template <typename T>
139        static inline T gtobe(T value) {return value;}
140        template <typename T>
141        static inline T betog(T value) {return value;}
142        template <typename T>
143        static inline T htog(T value) {return htobe(value);}
144        template <typename T>
145        static inline T gtoh(T value) {return betoh(value);}
146}
147
148namespace LittleEndianGuest
149{
150        template <typename T>
151        static inline T gtole(T value) {return value;}
152        template <typename T>
153        static inline T letog(T value) {return value;}
154        template <typename T>
155        static inline T gtobe(T value) {return letobe(value);}
156        template <typename T>
157        static inline T betog(T value) {return betole(value);}
158        template <typename T>
159        static inline T htog(T value) {return htole(value);}
160        template <typename T>
161        static inline T gtoh(T value) {return letoh(value);}
162}
163#endif // __SIM_BYTE_SWAP_HH__
164