byteswap.hh revision 3483 
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#elif defined (__sun__)
51#include <sys/isa_defs.h>
52#else
53#include <machine/endian.h>
54#endif
55
56#if defined(__APPLE__)
57#include <libkern/OSByteOrder.h>
58#endif
59
60//These functions actually perform the swapping for parameters
61//of various bit lengths
62static inline uint64_t
63swap_byte64(uint64_t x)
64{
65#if defined(linux)
66    return bswap_64(x);
67#elif defined(__APPLE__)
68    return OSSwapInt64(x);
69#else
70    return  (uint64_t)((((uint64_t)(x) & 0xff) << 56) |
71            ((uint64_t)(x) & 0xff00ULL) << 40 |
72            ((uint64_t)(x) & 0xff0000ULL) << 24 |
73            ((uint64_t)(x) & 0xff000000ULL) << 8 |
74            ((uint64_t)(x) & 0xff00000000ULL) >> 8 |
75            ((uint64_t)(x) & 0xff0000000000ULL) >> 24 |
76            ((uint64_t)(x) & 0xff000000000000ULL) >> 40 |
77            ((uint64_t)(x) & 0xff00000000000000ULL) >> 56) ;
78#endif
79}
80
81static inline uint32_t
82swap_byte32(uint32_t x)
83{
84#if defined(linux)
85    return bswap_32(x);
86#elif defined(__APPLE__)
87    return OSSwapInt32(x);
88#else
89    return  (uint32_t)(((uint32_t)(x) & 0xff) << 24 |
90            ((uint32_t)(x) & 0xff00) << 8 | ((uint32_t)(x) & 0xff0000) >> 8 |
91            ((uint32_t)(x) & 0xff000000) >> 24);
92#endif
93}
94
95static inline uint16_t
96swap_byte16(uint16_t x)
97{
98#if defined(linux)
99    return bswap_16(x);
100#elif defined(__APPLE__)
101    return OSSwapInt16(x);
102#else
103    return (uint16_t)(((uint16_t)(x) & 0xff) << 8 |
104                      ((uint16_t)(x) & 0xff00) >> 8);
105#endif
106}
107
108// This function lets the compiler figure out how to call the
109// swap_byte functions above for different data types.  Since the
110// sizeof() values are known at compiel time, it should inline to a
111// direct call to the right swap_byteNN() function.
112template <typename T>
113static inline T swap_byte(T x) {
114    if (sizeof(T) == 8)
115        return swap_byte64((uint64_t)x);
116    else if (sizeof(T) == 4)
117        return swap_byte32((uint32_t)x);
118    else if (sizeof(T) == 2)
119        return swap_byte16((uint16_t)x);
120    else if (sizeof(T) == 1)
121        return x;
122    else
123        panic("Can't byte-swap values larger than 64 bits");
124}
125
126//The conversion functions with fixed endianness on both ends don't need to
127//be in a namespace
128template <typename T> static inline T betole(T value) {return swap_byte(value);}
129template <typename T> static inline T letobe(T value) {return swap_byte(value);}
130
131//For conversions not involving the guest system, we can define the functions
132//conditionally based on the BYTE_ORDER macro and outside of the namespaces
133#if defined(_BIG_ENDIAN) || BYTE_ORDER == BIG_ENDIAN
134template <typename T> static inline T htole(T value) {return swap_byte(value);}
135template <typename T> static inline T letoh(T value) {return swap_byte(value);}
136template <typename T> static inline T htobe(T value) {return value;}
137template <typename T> static inline T betoh(T value) {return value;}
138#elif defined(_LITTLE_ENDIAN) || BYTE_ORDER == LITTLE_ENDIAN
139template <typename T> static inline T htole(T value) {return value;}
140template <typename T> static inline T letoh(T value) {return value;}
141template <typename T> static inline T htobe(T value) {return swap_byte(value);}
142template <typename T> static inline T betoh(T value) {return swap_byte(value);}
143#else
144        #error Invalid Endianess
145#endif
146
147namespace BigEndianGuest
148{
149        template <typename T>
150        static inline T gtole(T value) {return betole(value);}
151        template <typename T>
152        static inline T letog(T value) {return letobe(value);}
153        template <typename T>
154        static inline T gtobe(T value) {return value;}
155        template <typename T>
156        static inline T betog(T value) {return value;}
157        template <typename T>
158        static inline T htog(T value) {return htobe(value);}
159        template <typename T>
160        static inline T gtoh(T value) {return betoh(value);}
161}
162
163namespace LittleEndianGuest
164{
165        template <typename T>
166        static inline T gtole(T value) {return value;}
167        template <typename T>
168        static inline T letog(T value) {return value;}
169        template <typename T>
170        static inline T gtobe(T value) {return letobe(value);}
171        template <typename T>
172        static inline T betog(T value) {return betole(value);}
173        template <typename T>
174        static inline T htog(T value) {return htole(value);}
175        template <typename T>
176        static inline T gtoh(T value) {return letoh(value);}
177}
178#endif // __SIM_BYTE_SWAP_HH__
179