windows-nt/Source/XPSP1/NT/multimedia/directx/dsound/dsvxd/kegrace.cpp

//--------------------------------------------------------------------------;
//
//  File: kegrace.cpp
//
//  Copyright (c) 1995 Microsoft Corporation.  All Rights Reserved.
//
//  Abstract:
//
//  Contents:
//
//  History:
//      06/29/96    FrankYe     Created
//
//--------------------------------------------------------------------------;

#define NODSOUNDSERVICETABLE
#include "dsoundi.h"

// never premix less than this
#define MIN_PREMIX        45

#pragma VxD_LOCKED_CODE_SEG
#pragma VxD_LOCKED_DATA_SEG

extern "C" void KeGrace_GlobalTimeOutProcAsm();

LONG lMixerMutex;

LONG glNum;
DWORDLONG gdwlTotalWasted;
DWORDLONG gdwlTotal;
DWORDLONG _inline GetPentiumCounter(void)
{
   _asm  _emit 0x0F
   _asm  _emit 0x31
}

ULONG VXDINLINE VMM_Get_System_Time(void)
{
    ULONG Time;

    Touch_Register(eax);
    VMMCall(Get_System_Time);
    _asm mov Time, eax;
    return Time;
}

VOID _VMCPD_Get_Thread_State(PTCB Thread, PVOID pCPState)
{
    _asm mov esi, pCPState;
    _asm mov edi, Thread;
    VxDCall(VMCPD_Get_Thread_State);
}

VOID _VMCPD_Set_Thread_State(PTCB Thread, PVOID pCPState)
{
    _asm mov esi, pCPState;
    _asm mov edi, Thread;
    VxDCall(VMCPD_Set_Thread_State);
}

LONG _InterlockedExchange(PLONG pTarget, LONG Value)
{
    LONG OldTarget;
    _asm push edi;
    _asm mov eax, Value;
    _asm mov edi, pTarget;
    _asm xchg [edi], eax;
    _asm mov OldTarget, eax;
    _asm pop edi;
    return OldTarget;
}

// Must be in locked code
LONG _InterlockedExchangeAdd(PLONG pAddend, LONG Increment)
{
    LONG OldAddend;
    _asm mov esi, pAddend;
    _asm mov ecx, Increment;
    _asm mov eax, [esi];        // Read it (possibly causing a fault in)
    _asm add ecx, eax;
    _asm mov [esi], ecx;
    _asm mov OldAddend, eax;
    return OldAddend;
}

VOID _ZeroMemory(PVOID pDestination, DWORD cbLength)
{
    _asm mov edi, pDestination ;
    _asm mov esi, cbLength ;
    _asm xor eax, eax ;
    _asm mov ecx, esi ;
    _asm shr ecx, 2 ;
    _asm rep stosd ;
    _asm mov ecx, esi ;
    _asm and ecx, 3 ;
    _asm rep stosb ;
}
    
// Override the global new and delete operators
void * ::operator new(size_t size)
{ 
    return MemAlloc(size); 
}

void ::operator delete(void * pv) 
{ 
    MemFree(pv); 
}

// Implement our own purecall
int __cdecl _purecall(void)
{
    ASSERT(FALSE);
    return 0;
}

typedef struct tEVENTPARAMS {
    HTIMEOUT                hEvent;
    class CKeGrace          *pThis;
} EVENTPARAMS, *PEVENTPARAMS;

class CKeGrace : public CGrace {
    public:
        HRESULT             Initialize(CGrDest *pGrDest);
        void                Terminate(void);
        void                SignalRemix(void);
        int                 GetMaxRemix(void);
        void                GlobalTimeOutProc(int dtimeTardiness);

    private:
        static const int    MIXER_MINPREMIX;
        static const int    MIXER_MAXPREMIX;
        LONG                m_dtimePremix;
        LONG                m_ddtimePremix;
        EVENTPARAMS         m_EventParams;
        LONG                m_timeBusyWaitForMutex;
};

const int CKeGrace::MIXER_MINPREMIX = 45;
const int CKeGrace::MIXER_MAXPREMIX = 200;

extern "C" void KeGrace_GlobalTimeOutProc(PVOID pKeGrace, int dtimeTardiness)
{
    ((CKeGrace*)pKeGrace)->GlobalTimeOutProc(dtimeTardiness);
}

void CKeGrace::SignalRemix()
{
    HTIMEOUT hEvent;

#if 0
    // If you wanna run without remixing, just enable this bit of code.  You
    // might want to lower the MIXER_MAXPREMIX constant as well.
    m_fdwMixerSignal &= DSMIXERSIGNAL_REMIX;
    return;
#endif
    
    if (!(m_fdwMixerSignal & DSMIXERSIGNAL_REMIX))
    {
        m_fdwMixerSignal |= DSMIXERSIGNAL_REMIX;

        // Set a new time out for 2ms, and then cancel any prior pending timeout.
        //
        //  Note that "2ms" is somewhat arbitrary.  It just needs to be
        //  enough time to hopefully let this thread release the mixer
        //  mutex before the event executes.

        hEvent = Set_Global_Time_Out(KeGrace_GlobalTimeOutProcAsm, 2, (ULONG)&m_EventParams);
        hEvent = _InterlockedExchange((PLONG)&m_EventParams.hEvent, hEvent);
        Cancel_Time_Out(hEvent);
    }
}

void CKeGrace::GlobalTimeOutProc(int dtimeTardiness)
{
    char        CPState[108];        // Size of fp state per Intel prog. ref.
    LONG        dtime;
    LONG        dtimeSleep;
    LONG        dtimeInvalid;
    LONG        dtimeNextNotify;
    int         cSamplesPremixMax;
    int         cSamplesPremixed;

    // DPF(("CKeGrace::GlobalTimeOutProc"));

    if (m_dtimePremix/2 < dtimeTardiness) {
        DPF(("CKeGrace_GlobalTimeOutProc : warning: %dms late", dtimeTardiness));
    }

    //
    // We busy wait on the mutex, each iteration of the wait is longer
    // than the previous.
    //
    if (_InterlockedExchange(&lMixerMutex, TRUE)) {
        HTIMEOUT hEvent;
        LONG timeOut;
        // DPF(("CKeGrace::GlobalTimeOutProc : note: mutex already owned"));
        timeOut = _InterlockedExchangeAdd(&m_timeBusyWaitForMutex, 1);
        hEvent = Set_Global_Time_Out(KeGrace_GlobalTimeOutProcAsm, timeOut,
                                     (ULONG)&m_EventParams);
        hEvent = _InterlockedExchange((PLONG)&m_EventParams.hEvent, hEvent);
        Cancel_Time_Out(hEvent);
        return;
    }
    m_timeBusyWaitForMutex = 1;
    
    // Three cases:
    //   1) mixer is stopped
    //   2) mixer running and a remix is pending
    //   3) mixer running and no remix is pending
    //
    // Around each call to Refresh we need to save and restore the thread's
    // floating point state using the VMCPD Get/Set_Thread_State services.
    //

    if (MIXERSTATE_STOPPED == m_kMixerState) {
            
        dtimeSleep = 1000;        // arbitrarily set for 1 second

    } else {

        // DWORDLONG dwlStartCycle;
        // DWORDLONG dwlT;
        // dwlStartCycle = dwlT = GetPentiumCounter();

        dtime = VMM_Get_System_Time();

        _ZeroMemory(&CPState, sizeof(CPState));
        _VMCPD_Get_Thread_State(Get_Cur_Thread_Handle(), &CPState);

        // gdwlTotalWasted += GetPentiumCounter() - dwlT;
        // glNum++;

        if (m_fdwMixerSignal & DSMIXERSIGNAL_REMIX) {

            m_dtimePremix = MIXER_MINPREMIX;        // Initial premix length
            m_ddtimePremix = 2;                     // increment

            cSamplesPremixMax = MulDivRD(m_dtimePremix, m_pDest->m_nFrequency, 1000);
            Refresh(TRUE, cSamplesPremixMax, &cSamplesPremixed, &dtimeNextNotify);
        } else {

            m_dtimePremix += m_ddtimePremix;
            if (m_dtimePremix > MIXER_MAXPREMIX) {
                m_dtimePremix = MIXER_MAXPREMIX;
            } else {
                m_ddtimePremix += 2;
            }

            cSamplesPremixMax = MulDivRD(m_dtimePremix, m_pDest->m_nFrequency, 1000);
            Refresh(FALSE, cSamplesPremixMax, &cSamplesPremixed, &dtimeNextNotify);
        }

        // dwlT = GetPentiumCounter();
        
        _VMCPD_Set_Thread_State(Get_Cur_Thread_Handle(), &CPState);

        dtimeInvalid = MulDivRD(cSamplesPremixed, 1000, m_pDest->m_nFrequency);
        dtime = VMM_Get_System_Time() - dtime;
        dtimeInvalid -= 2 * dtime;

        dtimeSleep = min(dtimeNextNotify, dtimeInvalid/2);
        dtimeSleep = max(dtimeSleep, MIXER_MINPREMIX/2);

        // gdwlTotalWasted += GetPentiumCounter() - dwlT;
        // gdwlTotal += GetPentiumCounter() - dwlStartCycle;

    }

    // DPF(("CKeGrace::GlobalTimeOutProc : note: dtimeSleep=%dms", dtimeSleep));
    ASSERT(!m_EventParams.hEvent);
    m_EventParams.hEvent = Set_Global_Time_Out(KeGrace_GlobalTimeOutProcAsm, dtimeSleep, (ULONG)&m_EventParams);
    
    _InterlockedExchange(&lMixerMutex, FALSE);
}

HRESULT CKeGrace::Initialize(CGrDest *pDest)
{
    HRESULT hr;

    hr = CGrace::Initialize(pDest);
    if (S_OK != hr) return hr;
    
    DPF(("CKeGrace::Initialize : note: Setting up first GlobalTimeOut"));

    // If we want to run the timer really fast, do this.  So far I haven't seen
    // any empirical evidence of this helping.
    VTD_Begin_Min_Int_Period(5);

    m_dtimePremix = MIXER_MINPREMIX;        // Initial premix length
    m_ddtimePremix = 2;                     // increment

    // REMIND do error check
    m_timeBusyWaitForMutex = 1;
    m_EventParams.pThis = this;
    m_EventParams.hEvent = Set_Global_Time_Out(KeGrace_GlobalTimeOutProcAsm, 1, (ULONG)&m_EventParams);

    gdwlTotal = 0;
    gdwlTotalWasted = 0;
    glNum = 0;
    
    return hr;
}

//--------------------------------------------------------------------------;
//
// Terminate
//
// This function is called to terminate the grace mixer thread for the
// specified ds object.  It returns the handle to the thread that is being
// terminated.  After releasing any critical sections that the grace mixer
// thread may be waiting on, the caller should wait for the thread handle
// to become signaled.  For Win32 beginners: the thread handle is signalled
// after the thread terminates.
//
//--------------------------------------------------------------------------;

void CKeGrace::Terminate()
{
    HTIMEOUT        hEvent;

    hEvent = _InterlockedExchange((PLONG)&m_EventParams.hEvent, 0);
    Cancel_Time_Out(hEvent);

    CGrace::Terminate();

    if (0 != glNum) {
        DPF(("Wasted time = %d cycles", (int)(gdwlTotalWasted / glNum)));
        DPF(("Total  time = %d cycles", (int)(gdwlTotal       / glNum)));
    }
}

int CKeGrace::GetMaxRemix(void)
{
    // return max number of samples we might remix
    return (MulDivRU(MIXER_MAXPREMIX, m_pDest->m_nFrequency, 1000));
}


#pragma VxD_PAGEABLE_CODE_SEG
#pragma VxD_PAGEABLE_DATA_SEG

class CKeGrDest : public CGrDest {
public:
        CKeGrDest(LPNAGRDESTDATA);
        HRESULT Initialize(void);
        void Terminate(void);
        HRESULT SetFormat(LPWAVEFORMATEX pwfx);
        HRESULT AllocMixer(CMixer **ppMixer);
        void FreeMixer(void);
        HRESULT GetSamplePosition(int *pposPlay, int *pposWrite);
        HRESULT GetSamplePositionNoWin16(int *pposPlay, int *pposWrite);
        HRESULT Lock(PVOID *ppBuffer1, int *pcbBuffer1, PVOID *ppBuffer2, int *pcbBuffer2, int ibWrite, int cbWrite);
        HRESULT Unlock(PVOID pBuffer1, int cbBuffer1, PVOID pBuffer2, int cbBuffer2);
        void Play();
        void Stop();

    private:
        CKeGrace*   m_pKeGrace;
        DWORD       m_fdwDriverDesc;
        CBuf*       m_pDrvBuf;
        // Let's only send a stop if we are currently playing
        BOOL        m_fStopped;
};

CKeGrDest::CKeGrDest(LPNAGRDESTDATA pData)
{
    m_cbBuffer = pData->cbBuffer;
    m_pBuffer = pData->pBuffer;
    m_pDrvBuf = ((CBuf*)((PIDSDRIVERBUFFER)pData->hBuffer));
    m_fdwDriverDesc = pData->fdwDriverDesc;
    m_fStopped = TRUE;
}

HRESULT CKeGrDest::Initialize(void)
{
    m_cSamples = m_cbBuffer >> m_nBlockAlignShift;
    return DS_OK;
}

void CKeGrDest::Terminate(void)
{
    return;
}

HRESULT CKeGrDest::AllocMixer(CMixer **ppMixer)
{
    HRESULT hr;
    
    ASSERT(m_pBuffer);
    
    *ppMixer = NULL;
    
    m_pKeGrace = new CKeGrace;
    if (m_pKeGrace) {
        hr = m_pKeGrace->Initialize(this);
        if (S_OK != hr) {
            delete m_pKeGrace;
            m_pKeGrace = NULL;
        }
    } else {
        hr = DSERR_OUTOFMEMORY;
    }

    if (S_OK == hr) *ppMixer = m_pKeGrace;
    return hr;
}

void CKeGrDest::FreeMixer()
{
    ASSERT(m_pKeGrace);

    m_pKeGrace->Terminate();
    delete m_pKeGrace;
    m_pKeGrace = NULL;
}

HRESULT CKeGrDest::SetFormat(LPWAVEFORMATEX pwfx)
{
    HRESULT hr;

    SetFormatInfo(pwfx);
    hr = m_pDrvBuf->SetFormat(pwfx);
    return hr;
}

void CKeGrDest::Play()
{
    HRESULT hr;
    // REMIND we're not propagating errors here!
    hr = m_pDrvBuf->Play(0, 0, DSBPLAY_LOOPING);
    if (SUCCEEDED(hr)) m_fStopped = FALSE;
}

void CKeGrDest::Stop()
{
    HRESULT hr;
    if (m_fStopped == FALSE)
    {
        hr = m_pDrvBuf->Stop();
        if (SUCCEEDED(hr)) m_fStopped = TRUE;
    }
}
    
HRESULT CKeGrDest::Lock(PVOID *ppBuffer1, int *pcbBuffer1, PVOID *ppBuffer2, int *pcbBuffer2, int ibWrite, int cbWrite)
{
    LOCKCIRCULARBUFFER lcb;
    HRESULT            hr;
    
    lcb.pHwBuffer = m_pDrvBuf;
    lcb.pvBuffer = m_pBuffer;
    lcb.cbBuffer = m_cbBuffer;
    lcb.fPrimary = TRUE;
    lcb.fdwDriverDesc = m_fdwDriverDesc;
    lcb.ibRegion = ibWrite;
    lcb.cbRegion = cbWrite;

    hr = LockCircularBuffer(&lcb);

    if(SUCCEEDED(hr))
    {
        *ppBuffer1 = lcb.pvLock[0];
        *pcbBuffer1 = lcb.cbLock[0];

        if(ppBuffer2)
        {
            *ppBuffer2 = lcb.pvLock[1];
        }
        else
        {
            ASSERT(!lcb.pvLock[1]);
        }

        if(pcbBuffer2)
        {
            *pcbBuffer2 = lcb.cbLock[1];
        }
        else
        {
            ASSERT(!lcb.cbLock[1]);
        }
    }

    return hr;
}

HRESULT CKeGrDest::Unlock(PVOID pBuffer1, int cbBuffer1, PVOID pBuffer2, int cbBuffer2)
{
    LOCKCIRCULARBUFFER lcb;

    lcb.pHwBuffer = m_pDrvBuf;
    lcb.pvBuffer = m_pBuffer;
    lcb.cbBuffer = m_cbBuffer;
    lcb.fPrimary = TRUE;
    lcb.fdwDriverDesc = m_fdwDriverDesc;
    lcb.pvLock[0] = pBuffer1;
    lcb.cbLock[0] = cbBuffer1;
    lcb.pvLock[1] = pBuffer2;
    lcb.cbLock[1] = cbBuffer2;

    return UnlockCircularBuffer(&lcb);
}

HRESULT CKeGrDest::GetSamplePosition(int *pposPlay, int *pposWrite)
{
    HRESULT hr;
    DWORD dwPlay, dwWrite;

    ASSERT(pposPlay && pposWrite);
    
    hr = m_pDrvBuf->GetPosition(&dwPlay, &dwWrite);
    if (S_OK == hr) {

        *pposPlay = dwPlay >> m_nBlockAlignShift;
        *pposWrite = dwWrite >> m_nBlockAlignShift;

        // Until we write code to actually profile the performance, we'll just
        // pad the write position with a hard coded amount
        *pposWrite += m_nFrequency * HW_WRITE_CURSOR_MSEC_PAD / 1024;
        if (*pposWrite >= m_cSamples) *pposWrite -= m_cSamples;
        ASSERT(*pposWrite < m_cSamples);

    } else {
        *pposPlay = *pposWrite = 0;
    }

    return hr;
}

inline HRESULT CKeGrDest::GetSamplePositionNoWin16(int *pposPlay, int *pposWrite)
{
    return GetSamplePosition(pposPlay, pposWrite);
}

int ioctlMixer_Run(PDIOCPARAMETERS pdiocp)
{
    CMixer *pMixer;
    HRESULT hr;

    IOSTART(1*4);

    IOINPUT(pMixer, CMixer*);

    hr = pMixer->Run();

    IOOUTPUT(hr, HRESULT);
    IORETURN;
    return 0;
}

int ioctlMixer_Stop(PDIOCPARAMETERS pdiocp)
{
    BOOL f;
    CMixer *pMixer;

    IOSTART(1*4);

    IOINPUT(pMixer, CMixer*);

    f = pMixer->Stop();

    IOOUTPUT(f, BOOL);
    IORETURN;
    return 0;
}

int ioctlMixer_PlayWhenIdle(PDIOCPARAMETERS pdiocp)
{
    CMixer *pMixer;

    IOSTART(1*4);

    IOINPUT(pMixer, CMixer*);

    pMixer->PlayWhenIdle();

    IORETURN;
    return 0;
}

int ioctlMixer_StopWhenIdle(PDIOCPARAMETERS pdiocp)
{
    CMixer *pMixer;

    IOSTART(1*4);

    IOINPUT(pMixer, CMixer*);

    pMixer->StopWhenIdle();

    IORETURN;
    return 0;
}

int ioctlMixer_MixListAdd(PDIOCPARAMETERS pdiocp)
{
    CMixer *pMixer;
    CMixSource *pSource;

    IOSTART(2*4);

    IOINPUT(pMixer, CMixer*);
    IOINPUT(pSource, CMixSource*);

    pMixer->MixListAdd(pSource);

    IORETURN;
    return 0;
}

int ioctlMixer_MixListRemove(PDIOCPARAMETERS pdiocp)
{
    CMixer *pMixer;
    CMixSource *pSource;

    IOSTART(2*4);

    IOINPUT(pMixer, CMixer*);
    IOINPUT(pSource, CMixSource*);

    pMixer->MixListRemove(pSource);

    IORETURN;
    return 0;
}

int ioctlMixer_FilterOn(PDIOCPARAMETERS pdiocp)
{
    CMixer *pMixer;
    CMixSource *pSource;

    IOSTART(2*4);

    IOINPUT(pMixer, CMixer*);
    IOINPUT(pSource, CMixSource*);

    pMixer->FilterOn(pSource);

    IORETURN;
    return 0;
}

int ioctlMixer_FilterOff(PDIOCPARAMETERS pdiocp)
{
    CMixer *pMixer;
    CMixSource *pSource;

    IOSTART(2*4);

    IOINPUT(pMixer, CMixer*);
    IOINPUT(pSource, CMixSource*);

    pMixer->FilterOff(pSource);

    IORETURN;
    return 0;
}

int ioctlMixer_GetBytePosition(PDIOCPARAMETERS pdiocp)
{
    CMixer *pMixer;
    CMixSource *pSource;
    int *pibPlay;
    int *pibWrite;

    IOSTART(4*4);

    IOINPUT(pMixer, CMixer*);
    IOINPUT(pSource, CMixSource*);
    IOINPUT(pibPlay, int*);
    IOINPUT(pibWrite, int*);

    pMixer->GetBytePosition(pSource, pibPlay, pibWrite);

    IORETURN;
    return 0;
}

int ioctlMixer_SignalRemix(PDIOCPARAMETERS pdiocp)
{
    CMixer *pMixer;

    IOSTART(1*4);

    IOINPUT(pMixer, CMixer*);

    pMixer->SignalRemix();

    IORETURN;
    return 0;
}


int ioctlKeDest_New(PDIOCPARAMETERS pdiocp)
{
    LPNAGRDESTDATA pData;
    CKeGrDest *pKeGrDest;

    IOSTART(1*4);

    IOINPUT(pData, LPNAGRDESTDATA);
    
    pKeGrDest = new CKeGrDest(pData);

    IOOUTPUT(pKeGrDest, CKeGrDest*);
    IORETURN;
    return 0;
}

int ioctlMixDest_Delete(PDIOCPARAMETERS pdiocp)
{
    CMixDest *pMixDest;

    IOSTART(1*4);

    IOINPUT(pMixDest, CMixDest*);

    delete pMixDest;

    IORETURN;
    return 0;
}

int ioctlMixDest_Initialize(PDIOCPARAMETERS pdiocp)
{
    CMixDest *pMixDest;
    HRESULT hr;

    IOSTART(1*4);

    IOINPUT(pMixDest, CMixDest*);

    hr = pMixDest->Initialize();

    IOOUTPUT(hr, HRESULT);

    IORETURN;
    return 0;
}
    
int ioctlMixDest_Terminate(PDIOCPARAMETERS pdiocp)
{
    CMixDest *pMixDest;

    IOSTART(1*4);

    IOINPUT(pMixDest, CMixDest*);

    pMixDest->Terminate();

    IORETURN;
    return 0;
}
    
int ioctlMixDest_SetFormat(PDIOCPARAMETERS pdiocp)
{
    CMixDest *pMixDest;
    LPWAVEFORMATEX pwfx;
    HRESULT hr;

    IOSTART(2*4);

    IOINPUT(pMixDest, CMixDest*);
    IOINPUT(pwfx, LPWAVEFORMATEX);

    hr = pMixDest->SetFormat(pwfx);

    IOOUTPUT(hr, HRESULT);
    
    IORETURN;
    return 0;
}

int ioctlMixDest_SetFormatInfo(PDIOCPARAMETERS pdiocp)
{
    CMixDest *pMixDest;
    LPWAVEFORMATEX pwfx;

    IOSTART(2*4);

    IOINPUT(pMixDest, CMixDest*);
    IOINPUT(pwfx, LPWAVEFORMATEX);

    pMixDest->SetFormatInfo(pwfx);

    IORETURN;
    return 0;
}

int ioctlMixDest_AllocMixer(PDIOCPARAMETERS pdiocp)
{
    CMixDest *pMixDest;
    CMixer **ppMixer;
    HRESULT hr;

    IOSTART(2*4);

    IOINPUT(pMixDest, CMixDest*);
    IOINPUT(ppMixer, CMixer**);

    hr = pMixDest->AllocMixer(ppMixer);

    IOOUTPUT(hr, HRESULT);
    IORETURN;
    return 0;
}

int ioctlMixDest_FreeMixer(PDIOCPARAMETERS pdiocp)
{
    CMixDest *pMixDest;

    IOSTART(1*4);

    IOINPUT(pMixDest, CMixDest*);

    pMixDest->FreeMixer();

    IORETURN;
    return 0;
}

int ioctlMixDest_Play(PDIOCPARAMETERS pdiocp)
{
    CMixDest *pMixDest;

    IOSTART(1*4);

    IOINPUT(pMixDest, CMixDest*);

    pMixDest->Play();

    IORETURN;
    return 0;
}

int ioctlMixDest_Stop(PDIOCPARAMETERS pdiocp)
{
    CMixDest *pMixDest;

    IOSTART(1*4);

    IOINPUT(pMixDest, CMixDest*);

    pMixDest->Stop();

    IORETURN;
    return 0;
}

int ioctlMixDest_GetFrequency(PDIOCPARAMETERS pdiocp)
{
    CMixDest *pMixDest;
    int nFrequency;

    IOSTART(1*4);

    IOINPUT(pMixDest, CMixDest*);

    nFrequency = pMixDest->GetFrequency();

    IOOUTPUT(nFrequency, int);
    IORETURN;
    return 0;
}

int ioctlDsvxd_GetMixerMutexPtr(PDIOCPARAMETERS pdiocp)
{
    IOSTART(0*4);
    IOOUTPUT(&lMixerMutex, PLONG);
    IORETURN;
    return 0;
}