byteswap.hh revision 5549 
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/misc.hh"
42#include "sim/host.hh"
43
44// This lets us figure out what the byte order of the host system is
45#if defined(linux)
46#include <endian.h>
47// If this is a linux system, lets used the optimized definitions if they exist.
48// If one doesn't exist, we pretty much get what is listed below, so it all
49// works out
50#include <byteswap.h>
51#elif defined (__sun)
52#include <sys/isa_defs.h>
53#else
54#include <machine/endian.h>
55#endif
56
57#if defined(__APPLE__)
58#include <libkern/OSByteOrder.h>
59#endif
60
61enum ByteOrder {BigEndianByteOrder, LittleEndianByteOrder};
62
63//These functions actually perform the swapping for parameters
64//of various bit lengths
65inline uint64_t
66swap_byte64(uint64_t x)
67{
68#if defined(linux)
69    return bswap_64(x);
70#elif defined(__APPLE__)
71    return OSSwapInt64(x);
72#else
73    return  (uint64_t)((((uint64_t)(x) & 0xff) << 56) |
74            ((uint64_t)(x) & 0xff00ULL) << 40 |
75            ((uint64_t)(x) & 0xff0000ULL) << 24 |
76            ((uint64_t)(x) & 0xff000000ULL) << 8 |
77            ((uint64_t)(x) & 0xff00000000ULL) >> 8 |
78            ((uint64_t)(x) & 0xff0000000000ULL) >> 24 |
79            ((uint64_t)(x) & 0xff000000000000ULL) >> 40 |
80            ((uint64_t)(x) & 0xff00000000000000ULL) >> 56) ;
81#endif
82}
83
84inline uint32_t
85swap_byte32(uint32_t x)
86{
87#if defined(linux)
88    return bswap_32(x);
89#elif defined(__APPLE__)
90    return OSSwapInt32(x);
91#else
92    return  (uint32_t)(((uint32_t)(x) & 0xff) << 24 |
93            ((uint32_t)(x) & 0xff00) << 8 | ((uint32_t)(x) & 0xff0000) >> 8 |
94            ((uint32_t)(x) & 0xff000000) >> 24);
95#endif
96}
97
98inline uint16_t
99swap_byte16(uint16_t x)
100{
101#if defined(linux)
102    return bswap_16(x);
103#elif defined(__APPLE__)
104    return OSSwapInt16(x);
105#else
106    return (uint16_t)(((uint16_t)(x) & 0xff) << 8 |
107                      ((uint16_t)(x) & 0xff00) >> 8);
108#endif
109}
110
111// This function lets the compiler figure out how to call the
112// swap_byte functions above for different data types.  Since the
113// sizeof() values are known at compile time, it should inline to a
114// direct call to the right swap_byteNN() function.
115template <typename T>
116inline T swap_byte(T x) {
117    if (sizeof(T) == 8)
118        return swap_byte64((uint64_t)x);
119    else if (sizeof(T) == 4)
120        return swap_byte32((uint32_t)x);
121    else if (sizeof(T) == 2)
122        return swap_byte16((uint16_t)x);
123    else if (sizeof(T) == 1)
124        return x;
125    else
126        panic("Can't byte-swap values larger than 64 bits");
127}
128
129template<>
130inline Twin64_t swap_byte<Twin64_t>(Twin64_t x)
131{
132    x.a = swap_byte(x.a);
133    x.b = swap_byte(x.b);
134    return x;
135}
136
137template<>
138inline Twin32_t swap_byte<Twin32_t>(Twin32_t x)
139{
140    x.a = swap_byte(x.a);
141    x.b = swap_byte(x.b);
142    return x;
143}
144
145//The conversion functions with fixed endianness on both ends don't need to
146//be in a namespace
147template <typename T> inline T betole(T value) {return swap_byte(value);}
148template <typename T> inline T letobe(T value) {return swap_byte(value);}
149
150//For conversions not involving the guest system, we can define the functions
151//conditionally based on the BYTE_ORDER macro and outside of the namespaces
152#if defined(_BIG_ENDIAN) || !defined(_LITTLE_ENDIAN) && BYTE_ORDER == BIG_ENDIAN
153const ByteOrder HostByteOrder = BigEndianByteOrder;
154template <typename T> inline T htole(T value) {return swap_byte(value);}
155template <typename T> inline T letoh(T value) {return swap_byte(value);}
156template <typename T> inline T htobe(T value) {return value;}
157template <typename T> inline T betoh(T value) {return value;}
158#elif defined(_LITTLE_ENDIAN) || BYTE_ORDER == LITTLE_ENDIAN
159const ByteOrder HostByteOrder = LittleEndianByteOrder;
160template <typename T> inline T htole(T value) {return value;}
161template <typename T> inline T letoh(T value) {return value;}
162template <typename T> inline T htobe(T value) {return swap_byte(value);}
163template <typename T> inline T betoh(T value) {return swap_byte(value);}
164#else
165        #error Invalid Endianess
166#endif
167
168namespace BigEndianGuest
169{
170    const bool ByteOrderDiffers = (HostByteOrder != BigEndianByteOrder);
171    template <typename T>
172    inline T gtole(T value) {return betole(value);}
173    template <typename T>
174    inline T letog(T value) {return letobe(value);}
175    template <typename T>
176    inline T gtobe(T value) {return value;}
177    template <typename T>
178    inline T betog(T value) {return value;}
179    template <typename T>
180    inline T htog(T value) {return htobe(value);}
181    template <typename T>
182    inline T gtoh(T value) {return betoh(value);}
183}
184
185namespace LittleEndianGuest
186{
187    const bool ByteOrderDiffers = (HostByteOrder != LittleEndianByteOrder);
188    template <typename T>
189    inline T gtole(T value) {return value;}
190    template <typename T>
191    inline T letog(T value) {return value;}
192    template <typename T>
193    inline T gtobe(T value) {return letobe(value);}
194    template <typename T>
195    inline T betog(T value) {return betole(value);}
196    template <typename T>
197    inline T htog(T value) {return htole(value);}
198    template <typename T>
199    inline T gtoh(T value) {return letoh(value);}
200}
201#endif // __SIM_BYTE_SWAP_HH__
202