gem5/src/sim/byteswap.hh

179 lines
6.5 KiB
C++
Raw Normal View History

/*
* Copyright (c) 2004 The Regents of The University of Michigan
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met: redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer;
* redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution;
* neither the name of the copyright holders nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* Authors: Gabe Black
* Ali Saidi
* Nathan Binkert
*/
//The purpose of this file is to provide endainness conversion utility
//functions. Depending on the endianness of the guest system, either
//the LittleEndianGuest or BigEndianGuest namespace is used.
#ifndef __SIM_BYTE_SWAP_HH__
#define __SIM_BYTE_SWAP_HH__
#include "base/misc.hh"
#include "sim/host.hh"
// This lets us figure out what the byte order of the host system is
#if defined(linux)
#include <endian.h>
// If this is a linux system, lets used the optimized definitions if they exist.
// If one doesn't exist, we pretty much get what is listed below, so it all
// works out
#include <byteswap.h>
#elif defined (__sun__)
#include <sys/isa_defs.h>
#else
#include <machine/endian.h>
#endif
#if defined(__APPLE__)
#include <libkern/OSByteOrder.h>
#endif
//These functions actually perform the swapping for parameters
//of various bit lengths
static inline uint64_t
swap_byte64(uint64_t x)
{
#if defined(linux)
return bswap_64(x);
#elif defined(__APPLE__)
return OSSwapInt64(x);
#else
return (uint64_t)((((uint64_t)(x) & 0xff) << 56) |
((uint64_t)(x) & 0xff00ULL) << 40 |
((uint64_t)(x) & 0xff0000ULL) << 24 |
((uint64_t)(x) & 0xff000000ULL) << 8 |
((uint64_t)(x) & 0xff00000000ULL) >> 8 |
((uint64_t)(x) & 0xff0000000000ULL) >> 24 |
((uint64_t)(x) & 0xff000000000000ULL) >> 40 |
((uint64_t)(x) & 0xff00000000000000ULL) >> 56) ;
#endif
}
static inline uint32_t
swap_byte32(uint32_t x)
{
#if defined(linux)
return bswap_32(x);
#elif defined(__APPLE__)
return OSSwapInt32(x);
#else
return (uint32_t)(((uint32_t)(x) & 0xff) << 24 |
((uint32_t)(x) & 0xff00) << 8 | ((uint32_t)(x) & 0xff0000) >> 8 |
((uint32_t)(x) & 0xff000000) >> 24);
#endif
}
static inline uint16_t
swap_byte16(uint16_t x)
{
#if defined(linux)
return bswap_16(x);
#elif defined(__APPLE__)
return OSSwapInt16(x);
#else
return (uint16_t)(((uint16_t)(x) & 0xff) << 8 |
((uint16_t)(x) & 0xff00) >> 8);
#endif
}
// This function lets the compiler figure out how to call the
// swap_byte functions above for different data types. Since the
// sizeof() values are known at compiel time, it should inline to a
// direct call to the right swap_byteNN() function.
template <typename T>
static inline T swap_byte(T x) {
if (sizeof(T) == 8)
return swap_byte64((uint64_t)x);
else if (sizeof(T) == 4)
return swap_byte32((uint32_t)x);
else if (sizeof(T) == 2)
return swap_byte16((uint16_t)x);
else if (sizeof(T) == 1)
return x;
else
panic("Can't byte-swap values larger than 64 bits");
}
//The conversion functions with fixed endianness on both ends don't need to
//be in a namespace
template <typename T> static inline T betole(T value) {return swap_byte(value);}
template <typename T> static inline T letobe(T value) {return swap_byte(value);}
//For conversions not involving the guest system, we can define the functions
//conditionally based on the BYTE_ORDER macro and outside of the namespaces
#if defined(_BIG_ENDIAN) || BYTE_ORDER == BIG_ENDIAN
template <typename T> static inline T htole(T value) {return swap_byte(value);}
template <typename T> static inline T letoh(T value) {return swap_byte(value);}
template <typename T> static inline T htobe(T value) {return value;}
template <typename T> static inline T betoh(T value) {return value;}
#elif defined(_LITTLE_ENDIAN) || BYTE_ORDER == LITTLE_ENDIAN
template <typename T> static inline T htole(T value) {return value;}
template <typename T> static inline T letoh(T value) {return value;}
template <typename T> static inline T htobe(T value) {return swap_byte(value);}
template <typename T> static inline T betoh(T value) {return swap_byte(value);}
#else
#error Invalid Endianess
#endif
namespace BigEndianGuest
{
template <typename T>
static inline T gtole(T value) {return betole(value);}
template <typename T>
static inline T letog(T value) {return letobe(value);}
template <typename T>
static inline T gtobe(T value) {return value;}
template <typename T>
static inline T betog(T value) {return value;}
template <typename T>
static inline T htog(T value) {return htobe(value);}
template <typename T>
static inline T gtoh(T value) {return betoh(value);}
}
namespace LittleEndianGuest
{
template <typename T>
static inline T gtole(T value) {return value;}
template <typename T>
static inline T letog(T value) {return value;}
template <typename T>
static inline T gtobe(T value) {return letobe(value);}
template <typename T>
static inline T betog(T value) {return betole(value);}
template <typename T>
static inline T htog(T value) {return htole(value);}
template <typename T>
static inline T gtoh(T value) {return letoh(value);}
}
#endif // __SIM_BYTE_SWAP_HH__