byteswap.hh revision 2483 
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
29//The purpose of this file is to provide endainness conversion utility
30//functions. Depending on the endianness of the guest system, either
31//the LittleEndianGuest or BigEndianGuest namespace is used.
32
33#ifndef __SIM_BYTE_SWAP_HH__
34#define __SIM_BYTE_SWAP_HH__
35
36#include "sim/host.hh"
37
38// This lets us figure out what the byte order of the host system is
39#if defined(linux)
40#include <endian.h>
41#else
42#include <machine/endian.h>
43#endif
44
45//These functions actually perform the swapping for parameters
46//of various bit lengths
47static inline uint64_t
48swap_byte64(uint64_t x)
49{
50    return  (uint64_t)((((uint64_t)(x) & 0xff) << 56) |
51            ((uint64_t)(x) & 0xff00ULL) << 40 |
52            ((uint64_t)(x) & 0xff0000ULL) << 24 |
53            ((uint64_t)(x) & 0xff000000ULL) << 8 |
54            ((uint64_t)(x) & 0xff00000000ULL) >> 8 |
55            ((uint64_t)(x) & 0xff0000000000ULL) >> 24 |
56            ((uint64_t)(x) & 0xff000000000000ULL) >> 40 |
57            ((uint64_t)(x) & 0xff00000000000000ULL) >> 56) ;
58}
59
60static inline uint32_t
61swap_byte32(uint32_t x)
62{
63    return  (uint32_t)(((uint32_t)(x) & 0xff) << 24 |
64            ((uint32_t)(x) & 0xff00) << 8 | ((uint32_t)(x) & 0xff0000) >> 8 |
65            ((uint32_t)(x) & 0xff000000) >> 24);
66
67}
68
69static inline uint16_t
70swap_byte16(uint16_t x)
71{
72    return (uint16_t)(((uint16_t)(x) & 0xff) << 8 |
73                      ((uint16_t)(x) & 0xff00) >> 8);
74}
75
76//This lets the compiler figure out how to call the swap_byte functions above
77//for different data types.
78static inline uint64_t swap_byte(uint64_t x) {return swap_byte64(x);}
79static inline int64_t swap_byte(int64_t x) {return swap_byte64((uint64_t)x);}
80static inline uint32_t swap_byte(uint32_t x) {return swap_byte32(x);}
81static inline int32_t swap_byte(int32_t x) {return swap_byte32((uint32_t)x);}
82//This is to prevent the following two functions from compiling on
83//64bit machines. It won't detect everything, so it should be changed.
84#ifndef __x86_64__
85static inline long swap_byte(long x) {return swap_byte32((long)x);}
86static inline unsigned long swap_byte(unsigned long x)
87                                { return swap_byte32((unsigned long)x);}
88#endif
89static inline uint16_t swap_byte(uint16_t x) {return swap_byte32(x);}
90static inline int16_t swap_byte(int16_t x) {return swap_byte16((uint16_t)x);}
91static inline uint8_t swap_byte(uint8_t x) {return x;}
92static inline int8_t swap_byte(int8_t x) {return x;}
93static inline double swap_byte(double x) {return swap_byte64((uint64_t)x);}
94static inline float swap_byte(float x) {return swap_byte32((uint32_t)x);}
95
96//The conversion functions with fixed endianness on both ends don't need to
97//be in a namespace
98template <typename T> static inline T betole(T value) {return swap_byte(value);}
99template <typename T> static inline T letobe(T value) {return swap_byte(value);}
100
101//For conversions not involving the guest system, we can define the functions
102//conditionally based on the BYTE_ORDER macro and outside of the namespaces
103#if BYTE_ORDER == BIG_ENDIAN
104template <typename T> static inline T htole(T value) {return swap_byte(value);}
105template <typename T> static inline T letoh(T value) {return swap_byte(value);}
106template <typename T> static inline T htobe(T value) {return value;}
107template <typename T> static inline T betoh(T value) {return value;}
108#elif BYTE_ORDER == LITTLE_ENDIAN
109template <typename T> static inline T htole(T value) {return value;}
110template <typename T> static inline T letoh(T value) {return value;}
111template <typename T> static inline T htobe(T value) {return swap_byte(value);}
112template <typename T> static inline T betoh(T value) {return swap_byte(value);}
113#else
114        #error Invalid Endianess
115#endif
116
117namespace BigEndianGuest
118{
119        template <typename T>
120        static inline T gtole(T value) {return betole(value);}
121        template <typename T>
122        static inline T letog(T value) {return letobe(value);}
123        template <typename T>
124        static inline T gtobe(T value) {return value;}
125        template <typename T>
126        static inline T betog(T value) {return value;}
127        template <typename T>
128        static inline T htog(T value) {return htobe(value);}
129        template <typename T>
130        static inline T gtoh(T value) {return betoh(value);}
131}
132
133namespace LittleEndianGuest
134{
135        template <typename T>
136        static inline T gtole(T value) {return value;}
137        template <typename T>
138        static inline T letog(T value) {return value;}
139        template <typename T>
140        static inline T gtobe(T value) {return letobe(value);}
141        template <typename T>
142        static inline T betog(T value) {return betole(value);}
143        template <typename T>
144        static inline T htog(T value) {return htole(value);}
145        template <typename T>
146        static inline T gtoh(T value) {return letoh(value);}
147}
148#endif // __SIM_BYTE_SWAP_HH__
149