byteswap.hh revision 2779:b20a0595a0a3 
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
59static inline uint64_t
60swap_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
78static inline uint32_t
79swap_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
92static inline uint16_t
93swap_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.
109template <typename T>
110static 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
125template <typename T> static inline T betole(T value) {return swap_byte(value);}
126template <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
131template <typename T> static inline T htole(T value) {return swap_byte(value);}
132template <typename T> static inline T letoh(T value) {return swap_byte(value);}
133template <typename T> static inline T htobe(T value) {return value;}
134template <typename T> static inline T betoh(T value) {return value;}
135#elif BYTE_ORDER == LITTLE_ENDIAN
136template <typename T> static inline T htole(T value) {return value;}
137template <typename T> static inline T letoh(T value) {return value;}
138template <typename T> static inline T htobe(T value) {return swap_byte(value);}
139template <typename T> static inline T betoh(T value) {return swap_byte(value);}
140#else
141        #error Invalid Endianess
142#endif
143
144namespace 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
160namespace 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__
176