clock.h File Reference

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Classes
struct	_HARDWARE_TIMER

Macros
#define	HARDWARE_TIMER_ENABLED   (1 << 0)
#define	HARDWARE_TIMER_ONESHOT   (1 << 1)
#define	HARDWARE_TIMER_PRECISE   (1 << 2)
#define	HZ_TO_NS(Freq)   (ULONGLONG)(1000000000ULL / (ULONGLONG)(Freq))

Typedefs
typedef VOID(FASTCALL *	PHARDWARE_TIMER_PROC) (ULONGLONG ElapsedTime)
typedef struct _HARDWARE_TIMER	HARDWARE_TIMER
typedef struct _HARDWARE_TIMER *	PHARDWARE_TIMER

Functions
PHARDWARE_TIMER	CreateHardwareTimer (ULONG Flags, ULONGLONG Delay, PHARDWARE_TIMER_PROC Callback)
VOID	EnableHardwareTimer (PHARDWARE_TIMER Timer)
VOID	DisableHardwareTimer (PHARDWARE_TIMER Timer)
VOID	SetHardwareTimerDelay (PHARDWARE_TIMER Timer, ULONGLONG NewDelay)
VOID	DestroyHardwareTimer (PHARDWARE_TIMER Timer)
VOID	ClockUpdate (VOID)
BOOLEAN	ClockInitialize (VOID)

Variables
ULONGLONG	CurrentCycleCount
ULONGLONG	CurrentIps

Macro Definition Documentation

HARDWARE_TIMER_ENABLED

#define HARDWARE_TIMER_ENABLED   (1 << 0)

Definition at line 15 of file clock.h.

HARDWARE_TIMER_ONESHOT

#define HARDWARE_TIMER_ONESHOT   (1 << 1)

Definition at line 16 of file clock.h.

HARDWARE_TIMER_PRECISE

#define HARDWARE_TIMER_PRECISE   (1 << 2)

Definition at line 17 of file clock.h.

HZ_TO_NS

#define HZ_TO_NS

(

Freq

)

(ULONGLONG)(1000000000ULL / (ULONGLONG)(Freq))

Definition at line 20 of file clock.h.

Typedef Documentation

HARDWARE_TIMER

typedef struct _HARDWARE_TIMER HARDWARE_TIMER

PHARDWARE_TIMER

typedef struct _HARDWARE_TIMER * PHARDWARE_TIMER

PHARDWARE_TIMER_PROC

typedef VOID(FASTCALL * PHARDWARE_TIMER_PROC) (ULONGLONG ElapsedTime)

Definition at line 22 of file clock.h.

Function Documentation

ClockInitialize()

BOOLEAN ClockInitialize

(

VOID

)

Definition at line 219 of file clock.c.

{
    InitializeListHead(&Timers);
 
    /* Initialize the performance counter (needed for hardware timers) */
    /* Find the starting performance */
    NtQueryPerformanceCounter(&StartPerfCount, &Frequency);
    if (Frequency.QuadPart == 0)
    {
        wprintf(L"FATAL: Performance counter not available\n");
        return FALSE;
    }
 
    /* Find the starting tick count */
    // StartTickCount = GetTickCount();
 
    IpsTimer = CreateHardwareTimer(HARDWARE_TIMER_ENABLED, HZ_TO_NS(10), IpsCallback);
    if (IpsTimer == NULL)
    {
        wprintf(L"FATAL: Cannot create IPS timer.\n");
        return FALSE;
    }
 
    return TRUE;
}

Referenced by EmulatorInitialize().

ClockUpdate()

VOID ClockUpdate

(

VOID

)

DWORD_PTR oldmask = SetThreadAffinityMask(GetCurrentThread(), 0);

SetThreadAffinityMask(GetCurrentThread(), oldmask);

Definition at line 76 of file clock.c.

{
    extern BOOLEAN CpuRunning;
    UINT i;
    PLIST_ENTRY Entry;
    PHARDWARE_TIMER Timer;
 
    while (VdmRunning && CpuRunning)
    {
        /* Get the current counters */
        CurrentTickCount = GetTickCount();
        NtQueryPerformanceCounter(&Counter, NULL);
 
        /* Continue CPU emulation */
        for (i = 0; VdmRunning && CpuRunning && (i < STEPS_PER_CYCLE); i++)
        {
            CpuStep();
            ++CurrentCycleCount;
        }
 
        Entry = Timers.Flink;
        while (Entry != &Timers)
        {
            ULONGLONG Ticks = (ULONGLONG)-1;
 
            Timer = CONTAINING_RECORD(Entry, HARDWARE_TIMER, Link);
            Entry = Entry->Flink;
 
            ASSERT((Timer->EnableCount > 0) && (Timer->Flags & HARDWARE_TIMER_ENABLED));
 
            if (Timer->Delay)
            {
                if (Timer->Flags & HARDWARE_TIMER_PRECISE)
                {
                    /* Use the performance counter for precise timers */
                    if (Counter.QuadPart <= Timer->LastTick.QuadPart) continue;
                    Ticks = (Counter.QuadPart - Timer->LastTick.QuadPart) / Timer->Delay;
                }
                else
                {
                    /* Use the regular tick count for normal timers */
                    if (CurrentTickCount <= Timer->LastTick.LowPart) continue;
                    Ticks = (CurrentTickCount - Timer->LastTick.LowPart) / (ULONG)Timer->Delay;
                }
 
                if (Ticks == 0) continue;
            }
 
            Timer->Callback(Ticks);
 
            if (Timer->Flags & HARDWARE_TIMER_ONESHOT)
            {
                /* Disable this timer */
                DisableHardwareTimer(Timer);
            }
 
            /* Update the time of the last timer tick */
            Timer->LastTick.QuadPart += Ticks * Timer->Delay;
        }
 
        /* Yield execution to other threads */
        // FIXME: Disabled because it causes timing issues (slowdowns).
        // NtYieldExecution();
    }
}

Referenced by CpuSimulate().

CreateHardwareTimer()

PHARDWARE_TIMER CreateHardwareTimer	(	ULONG	Flags,
		ULONGLONG	Delay,
		PHARDWARE_TIMER_PROC	Callback
	)

Definition at line 144 of file clock.c.

{
    PHARDWARE_TIMER Timer;
 
    Timer = RtlAllocateHeap(RtlGetProcessHeap(), HEAP_ZERO_MEMORY, sizeof(*Timer));
    if (Timer == NULL) return NULL;
 
    Timer->Flags = Flags & ~HARDWARE_TIMER_ENABLED;
    Timer->EnableCount = 0;
    Timer->Callback = Callback;
    Timer->LastTick.QuadPart = 0;
    SetHardwareTimerDelay(Timer, Delay);
 
    if (Flags & HARDWARE_TIMER_ENABLED) EnableHardwareTimer(Timer);
    return Timer;
}

Referenced by ClockInitialize(), CmosInitialize(), MouseInit(), PitInitialize(), PS2Initialize(), and VgaInitialize().

DestroyHardwareTimer()

VOID DestroyHardwareTimer

(

PHARDWARE_TIMER

Timer

)

Definition at line 210 of file clock.c.

{
    if (Timer)
    {
        if (Timer->Flags & HARDWARE_TIMER_ENABLED) RemoveEntryList(&Timer->Link);
        RtlFreeHeap(RtlGetProcessHeap(), 0, Timer);
    }
}

Referenced by CmosCleanup(), PS2Cleanup(), and VgaCleanup().

DisableHardwareTimer()

VOID DisableHardwareTimer

(

PHARDWARE_TIMER

Timer

)

Definition at line 183 of file clock.c.

{
    /* Decrement the count */
    Timer->EnableCount--;
 
    /* Check if the count is 0 or less but the timer is enabled */
    if ((Timer->EnableCount <= 0) && (Timer->Flags & HARDWARE_TIMER_ENABLED))
    {
        /* Disable the timer */
        Timer->Flags &= ~HARDWARE_TIMER_ENABLED;
        RemoveEntryList(&Timer->Link);
    }
}

Referenced by ClockUpdate(), and RtcUpdatePeriodicTimer().

EnableHardwareTimer()

VOID EnableHardwareTimer

(

PHARDWARE_TIMER

Timer

)

Definition at line 161 of file clock.c.

{
    /* Increment the count */
    Timer->EnableCount++;
 
    /* Check if the count is above 0 but the timer isn't enabled */
    if ((Timer->EnableCount > 0) && !(Timer->Flags & HARDWARE_TIMER_ENABLED))
    {
        if (Timer->Flags & HARDWARE_TIMER_PRECISE)
        {
            NtQueryPerformanceCounter(&Timer->LastTick, NULL);
        }
        else
        {
            Timer->LastTick.LowPart = GetTickCount();
        }
 
        Timer->Flags |= HARDWARE_TIMER_ENABLED;
        InsertTailList(&Timers, &Timer->Link);
    }
}

Referenced by CreateHardwareTimer(), PS2QueuePush(), and RtcUpdatePeriodicTimer().

SetHardwareTimerDelay()

VOID SetHardwareTimerDelay	(	PHARDWARE_TIMER	Timer,
		ULONGLONG	NewDelay
	)

Definition at line 197 of file clock.c.

{
    if (Timer->Flags & HARDWARE_TIMER_PRECISE)
    {
        /* Convert the delay from nanoseconds to performance counter ticks */
        Timer->Delay = (NewDelay * Frequency.QuadPart + 500000000ULL) / 1000000000ULL;
    }
    else
    {
        Timer->Delay = NewDelay / 1000000ULL;
    }
}

Referenced by CreateHardwareTimer(), and RtcUpdatePeriodicTimer().

Variable Documentation

CurrentCycleCount

ULONGLONG CurrentCycleCount

extern

Definition at line 48 of file clock.c.

Referenced by ClockUpdate(), IpsCallback(), VgaHorizontalRetrace(), and VgaReadPort().

CurrentIps

ULONGLONG CurrentIps

extern

Definition at line 49 of file clock.c.

Referenced by IpsCallback(), VgaHorizontalRetrace(), and VgaReadPort().