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 );
}