Differential D2726 Diff 11861 source/lib/sysdep/os/win/whrt/counter.cpp

Changeset View

Standalone View

source/lib/sysdep/os/win/whrt/counter.cpp

	/* Copyright (C) 2010 Wildfire Games.			/* Copyright (C) 2020 Wildfire Games.
	*			*
	* Permission is hereby granted, free of charge, to any person obtaining			* Permission is hereby granted, free of charge, to any person obtaining
	* a copy of this software and associated documentation files (the			* a copy of this software and associated documentation files (the
	* "Software"), to deal in the Software without restriction, including			* "Software"), to deal in the Software without restriction, including
	* without limitation the rights to use, copy, modify, merge, publish,			* without limitation the rights to use, copy, modify, merge, publish,
	* distribute, sublicense, and/or sell copies of the Software, and to			* distribute, sublicense, and/or sell copies of the Software, and to
	* permit persons to whom the Software is furnished to do so, subject to			* permit persons to whom the Software is furnished to do so, subject to
	* the following conditions:			* the following conditions:
	Show All 15 Lines
	*/			*/

	#include "precompiled.h"			#include "precompiled.h"
	#include "lib/sysdep/os/win/whrt/counter.h"			#include "lib/sysdep/os/win/whrt/counter.h"

	#include "lib/alignment.h"			#include "lib/alignment.h"
	#include "lib/sysdep/cpu.h" // cpu_CAS			#include "lib/sysdep/cpu.h" // cpu_CAS

	#include "lib/sysdep/os/win/whrt/tsc.h"
	#include "lib/sysdep/os/win/whrt/hpet.h"
	#include "lib/sysdep/os/win/whrt/pmt.h"
	#include "lib/sysdep/os/win/whrt/qpc.h"			#include "lib/sysdep/os/win/whrt/qpc.h"
				#include "lib/sysdep/os/win/whrt/tsc.h"
	#include "lib/sysdep/os/win/whrt/tgt.h"			#include "lib/sysdep/os/win/whrt/tgt.h"
	// to add a new counter type, simply include its header here and			// to add a new counter type, simply include its header here and
	// insert a case in ConstructCounterAt's switch statement.			// insert a case in ConstructCounterAt's switch statement.


	//-----------------------------------------------------------------------------			//-----------------------------------------------------------------------------
	// create/destroy counters			// create/destroy counters

	/**			/**
	* @param id			* @param id
	* @param address			* @param address
	* @param size Maximum allowable size [bytes] of the subclass instance			* @param size Maximum allowable size [bytes] of the subclass instance
	* @return pointer to a newly constructed ICounter subclass of type \<id\> at			* @return pointer to a newly constructed ICounter subclass of type \<id\> at
	* the given address, or 0 iff the ID is invalid.			* the given address, or 0 iff the ID is invalid.
	**/			**/
	static ICounter* ConstructCounterAt(size_t id, void* address, size_t size)			static ICounter* ConstructCounterAt(size_t id, void* address, size_t size)
	{			{
	// rationale for placement new: see call site.			// rationale for placement new: see call site.

	// counters are chosen according to the following order. rationale:			// counters are chosen according to the following order. rationale:
	// - TSC must come before QPC and PMT to make sure a bug in the latter on			// - QPC is used by most games engines and is more stable than the others.
	// Pentium systems doesn't come up.			// - TSC is buggy on some machines like the AMD Zen 2 CPUs.
	// - PMT works, but is inexplicably slower than QPC on a PIII Mobile.
	// - TGT really isn't as safe as the others, so it should be last.			// - TGT really isn't as safe as the others, so it should be last.
	// - low-overhead and high-resolution counters are preferred.			// - low-overhead and high-resolution counters are preferred.
	switch(id)			switch(id)
	{			{
	case 0:			case 0:
	return CreateCounterHPET(address, size);			return CreateCounterQPC(address, size);
	case 1:			case 1:
	return CreateCounterTSC(address, size);			return CreateCounterTSC(address, size);
	case 2:			case 2:
	return CreateCounterQPC(address, size);
	case 3:
	return CreateCounterPMT(address, size);
	case 4:
	return CreateCounterTGT(address, size);			return CreateCounterTGT(address, size);
	default:			default:
	return 0;			return 0;
	}			}
	}			}


	static volatile intptr_t isCounterAllocated;			static volatile intptr_t isCounterAllocated;
	Show All 37 Lines