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tier1/reliabletimer.cpp

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+//========= Copyright Valve Corporation, All rights reserved. ============//
+//
+// Purpose: 
+//
+//=============================================================================
+
+#include "tier1/reliabletimer.h"
+
+int64 CReliableTimer::sm_nPerformanceFrequency = 0;
+bool CReliableTimer::sm_bUseQPC = false;
+
+#ifdef _WIN32
+#include "winlite.h"
+#endif
+
+//-----------------------------------------------------------------------------
+// Purpose: Constructor
+//-----------------------------------------------------------------------------
+CReliableTimer::CReliableTimer()
+{
+	m_nPerformanceCounterStart = 0;
+	m_nPerformanceCounterEnd = 0;
+	m_nPerformanceCounterLimit = 0;
+
+#ifdef _WIN32
+	// calculate performance frequency the first time we use a timer
+	if ( 0 == sm_nPerformanceFrequency )
+	{
+		// Are we on a bad CPU?
+		sm_bUseQPC = false; // todo
+		const CPUInformation &cpu = *GetCPUInformation();
+		sm_bUseQPC = ( ( 0 == Q_stricmp( cpu.m_szProcessorID, "AuthenticAMD" ) )
+			&& ( cpu.m_nPhysicalProcessors > 1 )
+			&& !cpu.m_bSSE41 );
+
+		if ( sm_bUseQPC )
+		{
+			LARGE_INTEGER li;
+			QueryPerformanceFrequency( &li );
+			sm_nPerformanceFrequency = li.QuadPart;
+		}
+		else
+		{
+			sm_nPerformanceFrequency = g_ClockSpeed;
+		}
+	}
+#elif defined(_PS3)
+	// On PowerPC, the time base register increment frequency is implementation dependent, and doesn't have to be constant.
+	// On PS3, measured it to be just shy of 80Mhz on the PPU and doesn't seem to change
+	if ( sm_nPerformanceFrequency == 0 )
+		sm_nPerformanceFrequency = sys_time_get_timebase_frequency(); 
+#else
+	// calculate performance frequency the first time we use a timer
+	if ( 0 == sm_nPerformanceFrequency )
+	{
+		sm_nPerformanceFrequency = g_ClockSpeed;
+	}
+#endif
+}
+
+
+//-----------------------------------------------------------------------------
+// Purpose: Returns current QueryPerformanceCounter value
+//-----------------------------------------------------------------------------
+int64 CReliableTimer::GetPerformanceCountNow()
+{
+	//VPROF_BUDGET( "CReliableTimer::GetPerformanceCountNow", VPROF_BUDGETGROUP_OTHER_UNACCOUNTED );
+#ifdef _WIN32
+	if ( sm_bUseQPC )
+	{
+		LARGE_INTEGER li = {0};
+		QueryPerformanceCounter( &li );
+		return li.QuadPart;
+	}
+	else
+	{
+		CCycleCount CycleCount;
+		CycleCount.Sample();
+		return CycleCount.GetLongCycles();
+	}
+#elif defined( _PS3 )
+	// use handy macro to grab tb
+	uint64 ulNow;
+	SYS_TIMEBASE_GET( ulNow );
+	return ulNow;
+#else
+	uint64 un64;
+	 __asm__ __volatile__ (
+                        "rdtsc\n\t"
+                        : "=A" (un64) );
+	return (int64)un64;
+#endif
+}