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forked from 0ad/0ad
0ad/source/lib/sysdep/cpu.h
janwas e14d5be529 timing-related fix (only occurs with certain timer resolutions due to incorrect arithmetic)
frequency_filter wasn't dealing correctly with resolution = 0
.. which was happening due to incorrect cpu_i64FromDouble macros

This was SVN commit r6200.
2008-07-05 08:27:33 +00:00

91 lines
2.5 KiB
C++

/**
* =========================================================================
* File : cpu.h
* Project : 0 A.D.
* Description : CPU and memory detection.
* =========================================================================
*/
// license: GPL; see lib/license.txt
#ifndef INCLUDED_CPU
#define INCLUDED_CPU
namespace ERR
{
const LibError CPU_FEATURE_MISSING = -130000;
const LibError CPU_UNKNOWN_OPCODE = -130001;
const LibError 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
/**
* 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 uintptr_t* location, uintptr_t expected, uintptr_t newValue);
/**
* specialization of cpu_CAS for pointer types. this avoids error-prone
* casting in user code.
**/
template<typename T>
bool cpu_CAS(volatile T* location, T expected, T new_value)
{
return cpu_CAS((volatile uintptr_t*)location, (uintptr_t)expected, (uintptr_t)new_value);
}
/**
* add a signed value to a variable without the possibility of interference
* from other threads/CPUs.
**/
LIB_API void cpu_AtomicAdd(volatile intptr_t* location, intptr_t increment);
/**
* enforce strict instruction ordering in the CPU pipeline.
**/
LIB_API void cpu_Serialize();
//-----------------------------------------------------------------------------
// misc
/**
* drop-in replacement for POSIX memcpy().
**/
LIB_API void* cpu_memcpy(void* RESTRICT dst, const void* RESTRICT src, size_t size);
/**
* set the FPU control word to "desirable" values (see implementation)
**/
LIB_API void cpu_ConfigureFloatingPoint();
// convert float to int much faster than _ftol2, which would normally be
// used by (int) casts.
// VC8 and GCC with -ffast-math now manage to generate SSE instructions,
// so our implementation is no longer needed.
#define cpu_i32FromFloat(f) ((i32)(f))
#define cpu_i32FromDouble(d) ((i32)(d))
#define cpu_i64FromDouble(d) ((i64)(d))
#endif // #ifndef INCLUDED_CPU