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0ad/source/lib/sysdep/cpu.h
2017-07-10 14:26:24 +00:00

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C++

/* Copyright (C) 2010 Wildfire Games.
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be included
* in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
/*
* CPU and memory detection.
*/
#ifndef INCLUDED_CPU
#define INCLUDED_CPU
#include "lib/sysdep/compiler.h"
namespace ERR
{
const Status CPU_FEATURE_MISSING = -130000;
const Status CPU_UNKNOWN_OPCODE = -130001;
const Status CPU_UNKNOWN_VENDOR = -130002;
}
//-----------------------------------------------------------------------------
// CPU detection
/**
* @return string identifying the CPU (usually a cleaned-up version of the
* brand string)
**/
LIB_API const char* cpu_IdentifierString();
//-----------------------------------------------------------------------------
// lock-free support routines
/**
* add a signed value to a variable without the possibility of interference
* from other threads/CPUs.
*
* @return the previous value.
**/
LIB_API intptr_t cpu_AtomicAdd(volatile intptr_t* location, intptr_t increment);
/**
* atomic "compare and swap".
*
* @param location address of the word to compare and possibly overwrite
* @param expected its expected value
* @param newValue the value with which to replace it
* @return false if the target word doesn't match the expected value,
* otherwise true (also overwriting the contents of location)
**/
LIB_API bool cpu_CAS(volatile intptr_t* location, intptr_t expected, intptr_t newValue);
LIB_API bool cpu_CAS64(volatile i64* location, i64 expected, i64 newValue);
/**
* specialization of cpu_CAS for pointer types. this avoids error-prone
* casting in user code.
**/
template<typename T>
inline bool cpu_CAS(volatile T* location, T expected, T new_value)
{
return cpu_CAS((volatile intptr_t*)location, (intptr_t)expected, (intptr_t)new_value);
}
LIB_API void cpu_Test();
/**
* pause in spin-wait loops, as a performance optimisation.
**/
inline void cpu_Pause()
{
#if MSC_VERSION && ARCH_X86_X64
_mm_pause();
#elif GCC_VERSION && ARCH_X86_X64
__asm__ __volatile__( "rep; nop" : : : "memory" );
#endif
}
#endif // #ifndef INCLUDED_CPU