byteswap.hh revision 3799 
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
60enum ByteOrder {BigEndianByteOrder, LittleEndianByteOrder};
61
62//These functions actually perform the swapping for parameters
63//of various bit lengths
64static inline uint64_t
65swap_byte64(uint64_t x)
66{
67#if defined(linux)
68    return bswap_64(x);
69#elif defined(__APPLE__)
70    return OSSwapInt64(x);
71#else
72    return  (uint64_t)((((uint64_t)(x) & 0xff) << 56) |
73            ((uint64_t)(x) & 0xff00ULL) << 40 |
74            ((uint64_t)(x) & 0xff0000ULL) << 24 |
75            ((uint64_t)(x) & 0xff000000ULL) << 8 |
76            ((uint64_t)(x) & 0xff00000000ULL) >> 8 |
77            ((uint64_t)(x) & 0xff0000000000ULL) >> 24 |
78            ((uint64_t)(x) & 0xff000000000000ULL) >> 40 |
79            ((uint64_t)(x) & 0xff00000000000000ULL) >> 56) ;
80#endif
81}
82
83static inline uint32_t
84swap_byte32(uint32_t x)
85{
86#if defined(linux)
87    return bswap_32(x);
88#elif defined(__APPLE__)
89    return OSSwapInt32(x);
90#else
91    return  (uint32_t)(((uint32_t)(x) & 0xff) << 24 |
92            ((uint32_t)(x) & 0xff00) << 8 | ((uint32_t)(x) & 0xff0000) >> 8 |
93            ((uint32_t)(x) & 0xff000000) >> 24);
94#endif
95}
96
97static inline uint16_t
98swap_byte16(uint16_t x)
99{
100#if defined(linux)
101    return bswap_16(x);
102#elif defined(__APPLE__)
103    return OSSwapInt16(x);
104#else
105    return (uint16_t)(((uint16_t)(x) & 0xff) << 8 |
106                      ((uint16_t)(x) & 0xff00) >> 8);
107#endif
108}
109
110// This function lets the compiler figure out how to call the
111// swap_byte functions above for different data types.  Since the
112// sizeof() values are known at compiel time, it should inline to a
113// direct call to the right swap_byteNN() function.
114template <typename T>
115static inline T swap_byte(T x) {
116    if (sizeof(T) == 8)
117        return swap_byte64((uint64_t)x);
118    else if (sizeof(T) == 4)
119        return swap_byte32((uint32_t)x);
120    else if (sizeof(T) == 2)
121        return swap_byte16((uint16_t)x);
122    else if (sizeof(T) == 1)
123        return x;
124    else
125        panic("Can't byte-swap values larger than 64 bits");
126}
127
128//The conversion functions with fixed endianness on both ends don't need to
129//be in a namespace
130template <typename T> static inline T betole(T value) {return swap_byte(value);}
131template <typename T> static inline T letobe(T value) {return swap_byte(value);}
132
133//For conversions not involving the guest system, we can define the functions
134//conditionally based on the BYTE_ORDER macro and outside of the namespaces
135#if defined(_BIG_ENDIAN) || BYTE_ORDER == BIG_ENDIAN
136const ByteOrder HostByteOrder = BigEndianByteOrder;
137template <typename T> static inline T htole(T value) {return swap_byte(value);}
138template <typename T> static inline T letoh(T value) {return swap_byte(value);}
139template <typename T> static inline T htobe(T value) {return value;}
140template <typename T> static inline T betoh(T value) {return value;}
141#elif defined(_LITTLE_ENDIAN) || BYTE_ORDER == LITTLE_ENDIAN
142const ByteOrder HostByteOrder = LittleEndianByteOrder;
143template <typename T> static inline T htole(T value) {return value;}
144template <typename T> static inline T letoh(T value) {return value;}
145template <typename T> static inline T htobe(T value) {return swap_byte(value);}
146template <typename T> static inline T betoh(T value) {return swap_byte(value);}
147#else
148        #error Invalid Endianess
149#endif
150
151namespace BigEndianGuest
152{
153    const bool ByteOrderDiffers = (HostByteOrder != BigEndianByteOrder);
154    template <typename T>
155    static inline T gtole(T value) {return betole(value);}
156    template <typename T>
157    static inline T letog(T value) {return letobe(value);}
158    template <typename T>
159    static inline T gtobe(T value) {return value;}
160    template <typename T>
161    static inline T betog(T value) {return value;}
162    template <typename T>
163    static inline T htog(T value) {return htobe(value);}
164    template <typename T>
165    static inline T gtoh(T value) {return betoh(value);}
166}
167
168namespace LittleEndianGuest
169{
170    const bool ByteOrderDiffers = (HostByteOrder != LittleEndianByteOrder);
171    template <typename T>
172    static inline T gtole(T value) {return value;}
173    template <typename T>
174    static inline T letog(T value) {return value;}
175    template <typename T>
176    static inline T gtobe(T value) {return letobe(value);}
177    template <typename T>
178    static inline T betog(T value) {return betole(value);}
179    template <typename T>
180    static inline T htog(T value) {return htole(value);}
181    template <typename T>
182    static inline T gtoh(T value) {return letoh(value);}
183}
184#endif // __SIM_BYTE_SWAP_HH__
185