byteswap.hh revision 11800:54436a1784dc 
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/bigint.hh"
41#include "base/types.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
62inline 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
81inline 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
95inline 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 compile time, it should inline to a
111// direct call to the right swap_byteNN() function.
112template <typename T>
113inline 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
126template<>
127inline Twin64_t swap_byte<Twin64_t>(Twin64_t x)
128{
129    x.a = swap_byte(x.a);
130    x.b = swap_byte(x.b);
131    return x;
132}
133
134template<>
135inline Twin32_t swap_byte<Twin32_t>(Twin32_t x)
136{
137    x.a = swap_byte(x.a);
138    x.b = swap_byte(x.b);
139    return x;
140}
141
142//The conversion functions with fixed endianness on both ends don't need to
143//be in a namespace
144template <typename T> inline T betole(T value) {return swap_byte(value);}
145template <typename T> inline T letobe(T value) {return swap_byte(value);}
146
147//For conversions not involving the guest system, we can define the functions
148//conditionally based on the BYTE_ORDER macro and outside of the namespaces
149#if (defined(_BIG_ENDIAN) || !defined(_LITTLE_ENDIAN)) && BYTE_ORDER == BIG_ENDIAN
150const ByteOrder HostByteOrder = BigEndianByteOrder;
151template <typename T> inline T htole(T value) {return swap_byte(value);}
152template <typename T> inline T letoh(T value) {return swap_byte(value);}
153template <typename T> inline T htobe(T value) {return value;}
154template <typename T> inline T betoh(T value) {return value;}
155#elif defined(_LITTLE_ENDIAN) || BYTE_ORDER == LITTLE_ENDIAN
156const ByteOrder HostByteOrder = LittleEndianByteOrder;
157template <typename T> inline T htole(T value) {return value;}
158template <typename T> inline T letoh(T value) {return value;}
159template <typename T> inline T htobe(T value) {return swap_byte(value);}
160template <typename T> inline T betoh(T value) {return swap_byte(value);}
161#else
162        #error Invalid Endianess
163#endif
164
165namespace BigEndianGuest
166{
167    const ByteOrder GuestByteOrder = BigEndianByteOrder;
168    template <typename T>
169    inline T gtole(T value) {return betole(value);}
170    template <typename T>
171    inline T letog(T value) {return letobe(value);}
172    template <typename T>
173    inline T gtobe(T value) {return value;}
174    template <typename T>
175    inline T betog(T value) {return value;}
176    template <typename T>
177    inline T htog(T value) {return htobe(value);}
178    template <typename T>
179    inline T gtoh(T value) {return betoh(value);}
180}
181
182namespace LittleEndianGuest
183{
184    const ByteOrder GuestByteOrder = LittleEndianByteOrder;
185    template <typename T>
186    inline T gtole(T value) {return value;}
187    template <typename T>
188    inline T letog(T value) {return value;}
189    template <typename T>
190    inline T gtobe(T value) {return letobe(value);}
191    template <typename T>
192    inline T betog(T value) {return betole(value);}
193    template <typename T>
194    inline T htog(T value) {return htole(value);}
195    template <typename T>
196    inline T gtoh(T value) {return letoh(value);}
197}
198#endif // __SIM_BYTE_SWAP_HH__
199