dolphin/Source/Core/VideoCommon/Src/Fifo.cpp

// Copyright (C) 2003-2008 Dolphin Project.

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, version 2.0.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License 2.0 for more details.

// A copy of the GPL 2.0 should have been included with the program.
// If not, see http://www.gnu.org/licenses/

// Official SVN repository and contact information can be found at
// http://code.google.com/p/dolphin-emu/

#include <string.h>

#include "MemoryUtil.h"
#include "Thread.h"
#include "OpcodeDecoding.h"

#include "Fifo.h"

extern u8* g_pVideoData;

bool fifoStateRun = true;

// STATE_TO_SAVE
static u8 *videoBuffer;
static int size = 0;

void Fifo_DoState(PointerWrap &p) 
{
    p.DoArray(videoBuffer, FIFO_SIZE);
    p.Do(size);
	int pos = (int)(g_pVideoData-videoBuffer); // get offset
	p.Do(pos); // read or write offset (depends on the mode afaik)
	g_pVideoData = &videoBuffer[pos]; // overwrite g_pVideoData -> expected no change when load ss and change when save ss
}

void Fifo_Init()
{
    videoBuffer = (u8*)AllocateMemoryPages(FIFO_SIZE);
    fifoStateRun = true;
}

void Fifo_Shutdown()
{
    FreeMemoryPages(videoBuffer, FIFO_SIZE);
    fifoStateRun = false;
}

void Fifo_Stop() 
{
    fifoStateRun = false;
}

u8* FAKE_GetFifoStartPtr()
{
    return videoBuffer;
}

u8* FAKE_GetFifoEndPtr()
{
	return &videoBuffer[size];
}

void Video_SendFifoData(u8* _uData)
{
	// TODO (mb2): unrolled loop faster than memcpy here?
    memcpy(videoBuffer + size, _uData, 32);
    size += 32;
    if (size + 32 >= FIFO_SIZE)
    {
		int pos = (int)(g_pVideoData-videoBuffer);
        if (size-pos > pos)
        {
            PanicAlert("FIFO out of bounds (sz = %i, at %08x)", size, pos);
        }
        memmove(&videoBuffer[0], &videoBuffer[pos], size - pos );
        size -= pos;
		g_pVideoData = FAKE_GetFifoStartPtr();
    }
    OpcodeDecoder_Run();
}


//TODO - turn inside out, have the "reader" ask for bytes instead
// See Core.cpp for threading idea
void Fifo_EnterLoop(const SVideoInitialize &video_initialize)
{
    SCPFifoStruct &_fifo = *video_initialize.pCPFifo;
#if defined(THREAD_VIDEO_WAKEUP_ONIDLE) && defined(_WIN32)
	HANDLE hEventOnIdle= OpenEventA(EVENT_ALL_ACCESS,FALSE,(LPCSTR)"EventOnIdle");
	if (hEventOnIdle==NULL) PanicAlert("Fifo_EnterLoop() -> EventOnIdle NULL");
#endif

#ifdef _WIN32
    // TODO(ector): Don't peek so often!
    while (video_initialize.pPeekMessages())
#else 
    while (fifoStateRun)
#endif
    {
#if defined(THREAD_VIDEO_WAKEUP_ONIDLE) && defined(_WIN32)
	if (MsgWaitForMultipleObjects(1, &hEventOnIdle, FALSE, 1L, QS_ALLEVENTS) == WAIT_ABANDONED)
		break;
#endif
        if (_fifo.CPReadWriteDistance < 1) 
        //if (_fifo.CPReadWriteDistance < _fifo.CPLoWatermark)
#if defined(THREAD_VIDEO_WAKEUP_ONIDLE) && defined(_WIN32)
            continue;
#else
			Common::SleepCurrentThread(1);
#endif
        //etc...

        // check if we are able to run this buffer
        if ((_fifo.bFF_GPReadEnable) && !(_fifo.bFF_BPEnable && _fifo.bFF_Breakpoint))
        {
#if defined(THREAD_VIDEO_WAKEUP_ONIDLE) && defined(_WIN32)
            while(_fifo.CPReadWriteDistance > 0)
#else
            while(_fifo.bFF_GPReadEnable && (_fifo.CPReadWriteDistance > 0) )// && count)
#endif
			{
                // check if we are on a breakpoint
                if (_fifo.bFF_BPEnable)
                {
					if (_fifo.CPReadPointer == _fifo.CPBreakpoint)
                    {
						video_initialize.pLog("!!! BP irq raised",FALSE);
                        #ifdef _WIN32
						InterlockedExchange((LONG*)&_fifo.bFF_Breakpoint, 1);
						#else
						Common::InterlockedExchange((int*)&_fifo.bFF_Breakpoint, 1);
						#endif
                        video_initialize.pUpdateInterrupts();
                        break;
                    }
                }

                // read the data and send it to the VideoPlugin
                u8 *uData = video_initialize.pGetMemoryPointer(_fifo.CPReadPointer);
#ifdef _WIN32
                //EnterCriticalSection(&_fifo.sync);
#else
                //                _fifo.sync->Enter();
#endif
                Video_SendFifoData(uData);
				// increase the ReadPtr
				u32 readPtr = _fifo.CPReadPointer+32;
                if (readPtr >= _fifo.CPEnd)
                    readPtr = _fifo.CPBase;				
#ifdef _WIN32
                InterlockedExchange((LONG*)&_fifo.CPReadPointer, readPtr);
                InterlockedExchangeAdd((LONG*)&_fifo.CPReadWriteDistance, -32);
                //LeaveCriticalSection(&_fifo.sync);
#else 
                Common::InterlockedExchange((int*)&_fifo.CPReadPointer, readPtr);
                Common::InterlockedExchangeAdd((int*)&_fifo.CPReadWriteDistance, -32);
                //                _fifo.sync->Leave();
#endif
            }
        }

    }
#if defined(THREAD_VIDEO_WAKEUP_ONIDLE) && defined(_WIN32)
	CloseHandle(hEventOnIdle);
#endif
}