source-engine/tier0/fasttimer.cpp
FluorescentCIAAfricanAmerican 3bf9df6b27 1
2020-04-22 12:56:21 -04:00

52 lines
1.5 KiB
C++

//========= Copyright Valve Corporation, All rights reserved. ============//
//
// Purpose:
//
// $NoKeywords: $
//=============================================================================//
#include "pch_tier0.h"
#include <stdio.h>
#include "tier0/fasttimer.h"
// g_dwClockSpeed is only exported for backwards compatibility.
PLATFORM_INTERFACE unsigned long g_dwClockSpeed;
uint64 g_ClockSpeed; // Clocks/sec
// Storing CPU clock speed in a 32-bit variable is dangerous and can already overflow
// on some CPUs. This variable is deprecated.
unsigned long g_dwClockSpeed;
#if defined( _X360 ) && defined( _CERT )
unsigned long g_dwFakeFastCounter;
#endif
double g_ClockSpeedMicrosecondsMultiplier;
double g_ClockSpeedMillisecondsMultiplier;
double g_ClockSpeedSecondsMultiplier;
// Constructor init the clock speed.
CClockSpeedInit g_ClockSpeedInit CONSTRUCT_EARLY;
void CClockSpeedInit::Init()
{
const CPUInformation& cpuinfo = *GetCPUInformation();
g_ClockSpeed = cpuinfo.m_Speed;
// cycle counter runs as doc'd at 1/64 Xbox 3.2GHz clock speed, thus 50 Mhz
if ( IsX360() )
{
g_ClockSpeed /= 64L;
}
// Avoid integer overflow when writing to g_dwClockSpeed
if ( g_ClockSpeed <= ULONG_MAX )
g_dwClockSpeed = (unsigned long)g_ClockSpeed;
else
g_dwClockSpeed = ULONG_MAX;
g_ClockSpeedMicrosecondsMultiplier = 1000000.0 / (double)g_ClockSpeed;
g_ClockSpeedMillisecondsMultiplier = 1000.0 / (double)g_ClockSpeed;
g_ClockSpeedSecondsMultiplier = 1.0 / (double)g_ClockSpeed;
}