byteswap.hh revision 2956 
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/misc.hh"
41#include "sim/host.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#else
51#include <machine/endian.h>
52#endif
53
54#if defined(__APPLE__)
55#include <libkern/OSByteOrder.h>
56#endif
57
58//These functions actually perform the swapping for parameters
59//of various bit lengths
60static inline uint64_t
61swap_byte64(uint64_t x)
62{
63#if defined(linux)
64    return bswap_64(x);
65#elif defined(__APPLE__)
66    return OSSwapInt64(x);
67#else
68    return  (uint64_t)((((uint64_t)(x) & 0xff) << 56) |
69            ((uint64_t)(x) & 0xff00ULL) << 40 |
70            ((uint64_t)(x) & 0xff0000ULL) << 24 |
71            ((uint64_t)(x) & 0xff000000ULL) << 8 |
72            ((uint64_t)(x) & 0xff00000000ULL) >> 8 |
73            ((uint64_t)(x) & 0xff0000000000ULL) >> 24 |
74            ((uint64_t)(x) & 0xff000000000000ULL) >> 40 |
75            ((uint64_t)(x) & 0xff00000000000000ULL) >> 56) ;
76#endif
77}
78
79static inline uint32_t
80swap_byte32(uint32_t x)
81{
82#if defined(linux)
83    return bswap_32(x);
84#elif defined(__APPLE__)
85    return OSSwapInt32(x);
86#else
87    return  (uint32_t)(((uint32_t)(x) & 0xff) << 24 |
88            ((uint32_t)(x) & 0xff00) << 8 | ((uint32_t)(x) & 0xff0000) >> 8 |
89            ((uint32_t)(x) & 0xff000000) >> 24);
90#endif
91}
92
93static inline uint16_t
94swap_byte16(uint16_t x)
95{
96#if defined(linux)
97    return bswap_16(x);
98#elif defined(__APPLE__)
99    return OSSwapInt16(x);
100#else
101    return (uint16_t)(((uint16_t)(x) & 0xff) << 8 |
102                      ((uint16_t)(x) & 0xff00) >> 8);
103#endif
104}
105
106// This function lets the compiler figure out how to call the
107// swap_byte functions above for different data types.  Since the
108// sizeof() values are known at compiel time, it should inline to a
109// direct call to the right swap_byteNN() function.
110template <typename T>
111static inline T swap_byte(T x) {
112    if (sizeof(T) == 8)
113        return swap_byte64((uint64_t)x);
114    else if (sizeof(T) == 4)
115        return swap_byte32((uint32_t)x);
116    else if (sizeof(T) == 2)
117        return swap_byte16((uint16_t)x);
118    else if (sizeof(T) == 1)
119        return x;
120    else
121        panic("Can't byte-swap values larger than 64 bits");
122}
123
124//The conversion functions with fixed endianness on both ends don't need to
125//be in a namespace
126template <typename T> static inline T betole(T value) {return swap_byte(value);}
127template <typename T> static inline T letobe(T value) {return swap_byte(value);}
128
129//For conversions not involving the guest system, we can define the functions
130//conditionally based on the BYTE_ORDER macro and outside of the namespaces
131#if BYTE_ORDER == BIG_ENDIAN
132template <typename T> static inline T htole(T value) {return swap_byte(value);}
133template <typename T> static inline T letoh(T value) {return swap_byte(value);}
134template <typename T> static inline T htobe(T value) {return value;}
135template <typename T> static inline T betoh(T value) {return value;}
136#elif BYTE_ORDER == LITTLE_ENDIAN
137template <typename T> static inline T htole(T value) {return value;}
138template <typename T> static inline T letoh(T value) {return value;}
139template <typename T> static inline T htobe(T value) {return swap_byte(value);}
140template <typename T> static inline T betoh(T value) {return swap_byte(value);}
141#else
142        #error Invalid Endianess
143#endif
144
145namespace BigEndianGuest
146{
147        template <typename T>
148        static inline T gtole(T value) {return betole(value);}
149        template <typename T>
150        static inline T letog(T value) {return letobe(value);}
151        template <typename T>
152        static inline T gtobe(T value) {return value;}
153        template <typename T>
154        static inline T betog(T value) {return value;}
155        template <typename T>
156        static inline T htog(T value) {return htobe(value);}
157        template <typename T>
158        static inline T gtoh(T value) {return betoh(value);}
159}
160
161namespace LittleEndianGuest
162{
163        template <typename T>
164        static inline T gtole(T value) {return value;}
165        template <typename T>
166        static inline T letog(T value) {return value;}
167        template <typename T>
168        static inline T gtobe(T value) {return letobe(value);}
169        template <typename T>
170        static inline T betog(T value) {return betole(value);}
171        template <typename T>
172        static inline T htog(T value) {return htole(value);}
173        template <typename T>
174        static inline T gtoh(T value) {return letoh(value);}
175}
176#endif // __SIM_BYTE_SWAP_HH__
177