byteswap.hh revision 2778:1bd913a180a1 
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 "sim/host.hh"
40
41// This lets us figure out what the byte order of the host system is
42#if defined(linux)
43#include <endian.h>
44// If this is a linux system, lets used the optimized definitions if they exist.
45// If one doesn't exist, we pretty much get what is listed below, so it all
46// works out
47#include <byteswap.h>
48#else
49#include <machine/endian.h>
50#endif
51
52#if defined(__APPLE__)
53#include <libkern/OSByteOrder.h>
54#endif
55
56//These functions actually perform the swapping for parameters
57//of various bit lengths
58static inline uint64_t
59swap_byte64(uint64_t x)
60{
61#if defined(linux)
62    return bswap_64(x);
63#elif defined(__APPLE__)
64    return OSSwapInt64(x);
65#else
66    return  (uint64_t)((((uint64_t)(x) & 0xff) << 56) |
67            ((uint64_t)(x) & 0xff00ULL) << 40 |
68            ((uint64_t)(x) & 0xff0000ULL) << 24 |
69            ((uint64_t)(x) & 0xff000000ULL) << 8 |
70            ((uint64_t)(x) & 0xff00000000ULL) >> 8 |
71            ((uint64_t)(x) & 0xff0000000000ULL) >> 24 |
72            ((uint64_t)(x) & 0xff000000000000ULL) >> 40 |
73            ((uint64_t)(x) & 0xff00000000000000ULL) >> 56) ;
74#endif
75}
76
77static inline uint32_t
78swap_byte32(uint32_t x)
79{
80#if defined(linux)
81    return bswap_32(x);
82#elif defined(__APPLE__)
83    return OSSwapInt32(x);
84#else
85    return  (uint32_t)(((uint32_t)(x) & 0xff) << 24 |
86            ((uint32_t)(x) & 0xff00) << 8 | ((uint32_t)(x) & 0xff0000) >> 8 |
87            ((uint32_t)(x) & 0xff000000) >> 24);
88#endif
89}
90
91static inline uint16_t
92swap_byte16(uint16_t x)
93{
94#if defined(linux)
95    return bswap_16(x);
96#elif defined(__APPLE__)
97    return OSSwapInt16(x);
98#else
99    return (uint16_t)(((uint16_t)(x) & 0xff) << 8 |
100                      ((uint16_t)(x) & 0xff00) >> 8);
101#endif
102}
103
104// This function lets the compiler figure out how to call the
105// swap_byte functions above for different data types.  Since the
106// sizeof() values are known at compiel time, it should inline to a
107// direct call to the right swap_byteNN() function.
108template <typename T>
109static inline T swap_byte(T x) {
110    if (sizeof(T) == 8)
111        return swap_byte64((uint64_t)x);
112    else if (sizeof(T) == 4)
113        return swap_byte32((uint32_t)x);
114    else if (sizeof(T) == 2)
115        return swap_byte16((uint16_t)x);
116    else if (sizeof(T) == 1)
117        return x;
118    else
119        panic("Can't byte-swap values larger than 64 bits");
120}
121
122//The conversion functions with fixed endianness on both ends don't need to
123//be in a namespace
124template <typename T> static inline T betole(T value) {return swap_byte(value);}
125template <typename T> static inline T letobe(T value) {return swap_byte(value);}
126
127//For conversions not involving the guest system, we can define the functions
128//conditionally based on the BYTE_ORDER macro and outside of the namespaces
129#if BYTE_ORDER == BIG_ENDIAN
130template <typename T> static inline T htole(T value) {return swap_byte(value);}
131template <typename T> static inline T letoh(T value) {return swap_byte(value);}
132template <typename T> static inline T htobe(T value) {return value;}
133template <typename T> static inline T betoh(T value) {return value;}
134#elif BYTE_ORDER == LITTLE_ENDIAN
135template <typename T> static inline T htole(T value) {return value;}
136template <typename T> static inline T letoh(T value) {return value;}
137template <typename T> static inline T htobe(T value) {return swap_byte(value);}
138template <typename T> static inline T betoh(T value) {return swap_byte(value);}
139#else
140        #error Invalid Endianess
141#endif
142
143namespace BigEndianGuest
144{
145        template <typename T>
146        static inline T gtole(T value) {return betole(value);}
147        template <typename T>
148        static inline T letog(T value) {return letobe(value);}
149        template <typename T>
150        static inline T gtobe(T value) {return value;}
151        template <typename T>
152        static inline T betog(T value) {return value;}
153        template <typename T>
154        static inline T htog(T value) {return htobe(value);}
155        template <typename T>
156        static inline T gtoh(T value) {return betoh(value);}
157}
158
159namespace LittleEndianGuest
160{
161        template <typename T>
162        static inline T gtole(T value) {return value;}
163        template <typename T>
164        static inline T letog(T value) {return value;}
165        template <typename T>
166        static inline T gtobe(T value) {return letobe(value);}
167        template <typename T>
168        static inline T betog(T value) {return betole(value);}
169        template <typename T>
170        static inline T htog(T value) {return htole(value);}
171        template <typename T>
172        static inline T gtoh(T value) {return letoh(value);}
173}
174#endif // __SIM_BYTE_SWAP_HH__
175