beep.c File Reference

#include <hal.h>
#include <debug.h>

Include dependency graph for beep.c:

Go to the source code of this file.

Macros
#define	NDEBUG

Functions
BOOLEAN NTAPI	HalMakeBeep (_In_ ULONG Frequency)

Macro Definition Documentation

NDEBUG

#define NDEBUG

Definition at line 12 of file beep.c.

Function Documentation

HalMakeBeep()

BOOLEAN NTAPI HalMakeBeep

(

_In_ ULONG

Frequency

)

Definition at line 19 of file beep.c.

{
    TIMER_CONTROL_PORT_REGISTER TimerControl;
    ULONG Divider;
    BOOLEAN Success = FALSE;
 
    HalpAcquireCmosSpinLock();
 
    __outbyte(PPI_IO_o_CONTROL, PPI_TIMER_1_UNGATE_TO_SPEAKER);
 
    if (Frequency)
    {
        Divider = PIT_FREQUENCY / Frequency;
 
        if (Divider <= 0x10000)
        {
            TimerControl.BcdMode = FALSE;
            TimerControl.OperatingMode = PitOperatingMode3;
            TimerControl.Channel = PitChannel1;
            TimerControl.AccessMode = PitAccessModeLowHigh;
            __outbyte(TIMER_CONTROL_PORT, TimerControl.Bits);
            __outbyte(TIMER_CHANNEL1_DATA_PORT, FIRSTBYTE(Divider));
            __outbyte(TIMER_CHANNEL1_DATA_PORT, SECONDBYTE(Divider));
 
            __outbyte(PPI_IO_o_CONTROL, PPI_TIMER_1_GATE_TO_SPEAKER);
 
            Success = TRUE;
        }
    }
 
    HalpReleaseCmosSpinLock();
 
    return Success;
}