Limit the current thread to one processor

//--------------------------------------------------------------------------------------
// Limit the current thread to one processor (the current one). This ensures that timing code
// runs on only one processor, and will not suffer any ill effects from power management.
// See "Game Timing and Multicore Processors" for more details
//--------------------------------------------------------------------------------------
void LimitThreadAffinityToCurrentProc()
{
HANDLE hCurrentProcess = GetCurrentProcess();

// Get the processor affinity mask for this process
DWORD_PTR dwProcessAffinityMask = 0;
DWORD_PTR dwSystemAffinityMask = 0;

if( GetProcessAffinityMask( hCurrentProcess, &dwProcessAffinityMask, &dwSystemAffinityMask ) != 0 &&
dwProcessAffinityMask )
{
// Find the lowest processor that our process is allows to run against
DWORD_PTR dwAffinityMask = ( dwProcessAffinityMask & ( ( ~dwProcessAffinityMask ) + 1 ) );

// Set this as the processor that our thread must always run against
// This must be a subset of the process affinity mask
HANDLE hCurrentThread = GetCurrentThread();
if( INVALID_HANDLE_VALUE != hCurrentThread )
{
SetThreadAffinityMask( hCurrentThread, dwAffinityMask );
CloseHandle( hCurrentThread );
}
}

CloseHandle( hCurrentProcess );
}