/**
** Supermodel
** A Sega Model 3 Arcade Emulator.
** Copyright 2011 Bart Trzynadlowski, Nik Henson
**
** This file is part of Supermodel.
**
** Supermodel 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, either version 3 of the License, or (at your option)
** any later version.
**
** Supermodel 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 for
** more details.
**
** You should have received a copy of the GNU General Public License along
** with Supermodel. If not, see .
**/
/*
* DSB.cpp
*
* Sega Digital Sound Board (MPEG audio). Implementation of the CDSB1 and CDSB2
* classes. Based on code donated by R. Belmont. Many Bothans died to bring us
* this emulation.
*
* TODO List
* ---------
* - Should MPEG_SetLoop() check for loopEnd==0? This causes crashes. Usually
* only occurs when loopStart is also 0, and that can only be checked here.
* - Volume fade out in Daytona 2 is much too slow. Probably caused by 68K
* timing or interrupts.
* - Check actual MPEG sample rate. So far, all games seem to use 32 KHz, which
* may be a hardware requirement, but if other sampling rates are allowable,
* the code here will fail (it is hard coded for 32 KHz).
* - Should we do some bounds checking on the MPEG start/end points?
*/
#include "Supermodel.h"
/******************************************************************************
Resampler
MPEG Layer 2 audio can be 32, 44.1, or 48 KHz. Here, an up-sampling algorithm
is provided, which should work for any frequency less than 44.1 KHz and an
output frequency of 44.1 KHz. Down-sampling is not yet implemented, but would
work in a similar fashion. The chief difference is that the input index would
sometimes advance by more than one for a single output sample and the
fractions, nFrac and pFrac, would sometimes exceed 1.0.
Up-Sampling Description
-----------------------
Linear interpolation is used to up-sample. Not as accurate as the Shannon
reconstruction equation but it seems to work quite well.
1. Linear Interpolation
Input samples for a given frame (here, this means 1/60Hz, not to be confused
with an MPEG frame, which is shorter) are numbered 0 ... L-1 (L samples in
total). Output samples are 0 ... M-1.
For two adjacent input samples at times p ("previous") and n ("next"), in[p]
and in[n], and output out[t] at time t, linear interpolation yields:
out[t] = (n-t)/(n-p) * in[p] + (t-p)/(n-p) * in[n]
Note that (n-p) = 1/fin (fin being the input sampling frequency).
Let pFrac = (n-t)/(n-p) and nFrac = (t-p)/(n-p). As t moves from p to n, pFrac
moves from 1 to 0 and nFrac from 0 to 1, as we expect.
If we proceed one output sample at a time, we must add the time difference
between output samples, 1/fout, to t. Call this delta_t. If we divide delta_t
by (n-p), we can add it directly to nFrac and subtract from pFrac. Therefore:
delta = (1/fout)/(n-p) = fin/fout
What happens when nFrac exceeds 1.0 or pFrac goes below 0.0? That can't
be allowed to happen -- it means that we've actually moved along the line into
the region between the next set of samples. We use pFrac < 0 as the condition
to update the input samples.
It so happens that when fin < fout, pFrac and nFrac will never exceed 1.0. So
there is no need to check or mask the fixed point values when using them to
interpolate samples.
2. Input Buffer Overflows
For some low sampling rates, particularly those that are a factor of 2 or 4
smaller, it is possible that the very last sample or two needed from the input
stream will be beyond the end. Fetching two extra samples (which can introduce
an update lag of two samples -- imperceptible and inconsequential) fixes this,
and so we do it.
3. Continuity Between Frames
The very last output sample will typically sit somewhere between two input
samples. It is wrong to start the next frame by assuming everything is lined
up again. The first sample of the next frame will often have to be interpol-
ated with the last sample of the previous frame. To facilitate this, we check
to see how many input samples remain unprocessed when up-sampling is finished,
and then copy those to the beginning of the buffer. We then return the number
of samples so that the buffer update function will know to skip them.
We also must maintain the state of pFrac and nFrac to resume interpolation
correctly. Therefore, these variables are persistent.
4. Fixed Point Arithmetic
Fixed point arithmetic is used to track fractions. For such numbers, the low
8 bits represent a fraction (0x100 would be 1.0, 0x080 would be 0.5, etc.)
and the upper bits are the integral portion.
******************************************************************************/
void CDSBResampler::Reset(void)
{
// Initial state of fractions (24.8 fixed point)
nFrac = 0<<8; // fraction of next sample to use (0->1.0 as x moves p->n)
pFrac = 1<<8; // previous sample (1.0->0 as x moves p->n)
}
// Mixes 16-bit samples (sign extended in a and b)
static inline INT16 MixAndClip(INT32 a, INT32 b)
{
a += b;
if (a > 32767)
a = 32767;
else if (a < -32768)
a = -32768;
return (INT16) a;
}
// Mixes audio and returns number of samples copied back to start of buffer (ie. offset at which new samples should be written)
int CDSBResampler::UpSampleAndMix(INT16 *outL, INT16 *outR, INT16 *inL, INT16 *inR, UINT8 volumeL, UINT8 volumeR, int sizeOut, int sizeIn, int outRate, int inRate)
{
int delta = (inRate<<8)/outRate; // (1/fout)/(1/fin)=fin/fout, 24.8 fixed point
int outIdx = 0;
int inIdx = 0;
INT32 leftSample, rightSample, leftSoundSample, rightSoundSample;
INT32 v[2], musicVol, soundVol;
// Obtain program volume settings and convert to 24.8 fixed point (0-200 -> 0x00-0x200)
musicVol = m_config["MusicVolume"].ValueAs();
soundVol = m_config["SoundVolume"].ValueAs();
musicVol = (INT32) ((float) 0x100 * (float) musicVol / 100.0f);
soundVol = (INT32) ((float) 0x100 * (float) soundVol / 100.0f);
// Scale volume from 0x00-0xFF -> 0x00-0x100 (24.8 fixed point)
v[0] = (INT16) ((float) 0x100 * (float) volumeL / 255.0f);
v[1] = (INT16) ((float) 0x100 * (float) volumeR / 255.0f);
// Up-sample and mix!
while (outIdx < sizeOut)
{
// nFrac, pFrac will never exceed 1.0 (0x100) (only true if delta does not exceed 1)
leftSample = ((int)inL[inIdx]*pFrac+(int)inL[inIdx+1]*nFrac) >> 8; // left channel
rightSample = ((int)inR[inIdx]*pFrac+(int)inR[inIdx+1]*nFrac) >> 8; // right channel
// Apply DSB volume and then overall music volume setting
leftSample = (leftSample*v[0]*musicVol) >> 16; // multiplied by two 24.8 numbers, shift back by 16
rightSample = (rightSample*v[0]*musicVol) >> 16;
// Apply sound volume setting
leftSoundSample = (outL[outIdx]*soundVol) >> 8;
rightSoundSample = (outR[outIdx]*soundVol) >> 8;
// Mix and output
outL[outIdx] = MixAndClip(leftSoundSample, leftSample);
outR[outIdx] = MixAndClip(rightSoundSample, rightSample);
outIdx++;
// Time step
pFrac -= delta;
nFrac += delta;
// Time to move to next samples?
if (pFrac <= 0) // when pFrac becomes 0, advance samples, reset pFrac to 1
{
pFrac += (1<<8);
nFrac -= (1<<8);
inIdx++; // advance samples (for upsampling only; downsampling may advance by more than one -- add delta every loop iteration)
}
}
// Copy remaining "active" input samples to start of buffer
int i = 0;
int j = inIdx;
while (j < sizeIn)
{
inL[i] = inL[j];
inR[i] = inR[j];
i++;
j++;
}
return i; // first free position in input buffer to copy next MPEG update to
}
/******************************************************************************
Digital Sound Board Type 1: Z80 CPU
******************************************************************************/
UINT8 CDSB1::Read8(UINT32 addr)
{
// ROM: 0x0000-0x7FFF
if (addr < 0x8000)
return progROM[addr];
// RAM: 0x8000-0xFFFF
return ram[addr&0x7FFF];
}
void CDSB1::Write8(UINT32 addr, UINT8 data)
{
if (addr >= 0x8000)
ram[addr&0x7FFF] = data;
}
void CDSB1::IOWrite8(UINT32 addr, UINT8 data)
{
switch ((addr&0xFF))
{
case 0xE0: // MPEG trigger
mpegState = data;
if (data == 0) // stop
{
MPEG_StopPlaying();
return;
}
if (data == 1) // play without loop
{
//printf("====> Playing %06X (mpegEnd=%06X)\n", mpegStart, mpegEnd);
MPEG_SetLoop(NULL, 0);
usingLoopStart = 0; // save the settings of the MPEG currently playing
usingLoopEnd = 0;
usingMPEGStart = mpegStart;
usingMPEGEnd = mpegEnd;
MPEG_PlayMemory((const char *) &mpegROM[mpegStart], mpegEnd-mpegStart);
return;
}
if (data == 2) // play with loop (NOTE: I don't think this actually loops b/c MPEG_PlayMemory() clears lstart)
{
//printf("====> Playing w/ loop %06X (mpegEnd=%06X, loopStart=%06X, loopEnd=%06X)\n", mpegStart, mpegEnd, loopStart, loopEnd);
usingLoopStart = 0; // MPEG_PlayMemory() clears these settings and Z80 will set them up later
usingLoopEnd = 0;
usingMPEGStart = mpegStart;
usingMPEGEnd = mpegEnd;
MPEG_PlayMemory((const char *) &mpegROM[mpegStart], mpegEnd-mpegStart);
return;
}
break;
case 0xE2: // MPEG start, high byte
startLatch &= 0x00FFFF;
startLatch |= ((UINT32)data) << 16;
break;
case 0xE3: // MPEG start, middle byte
startLatch &= 0xFF00FF;
startLatch |= ((UINT32)data) << 8;
break;
case 0xE4: // MPEG start, low byte
startLatch &= 0xFFFF00;
startLatch |= data;
if (mpegState == 0)
{
mpegStart = startLatch;
//printf("mpegStart = %08X\n", mpegStart);
}
else
{
loopStart = startLatch;
//printf("loopStart = %08X\n", loopStart);
// SWA: if loop end is zero, it means "keep previous end marker"
if (loopEnd == 0)
{
usingLoopStart = loopStart;
usingLoopEnd = mpegEnd-loopStart;
MPEG_SetLoop((const char *) &mpegROM[usingLoopStart], usingLoopEnd);
}
else
{
usingLoopStart = loopStart;
usingLoopEnd = loopEnd-loopStart;
MPEG_SetLoop((const char *) &mpegROM[usingLoopStart], usingLoopEnd);
}
}
break;
case 0xE5: // MPEG end, high byte
endLatch &= 0x00FFFF;
endLatch |= ((UINT32)data) << 16;
break;
case 0xE6: // MPEG end, middle byte
endLatch &= 0xFF00FF;
endLatch |= ((UINT32)data) << 8;
break;
case 0xE7: // MPEG end, low byte
endLatch &= 0xFFFF00;
endLatch |= data;
if (mpegState == 0)
{
mpegEnd = endLatch;
//printf("mpegEnd = %08X\n", mpegEnd);
}
else
{
loopEnd = endLatch;
//printf("loopEnd = %08X\n", loopEnd);
usingLoopStart = loopStart;
usingLoopEnd = loopEnd-loopStart;
MPEG_SetLoop((const char *) &mpegROM[usingLoopStart], usingLoopEnd);
}
break;
case 0xE8: // MPEG volume
volume = 0x7F-data;
//printf("Set Volume: %02X\n", volume);
break;
case 0xE9: // MPEG stereo
stereo = data;
break;
case 0xF0: // command echo back
break;
default:
//printf("Z80 Port %02X=%08X\n", addr, data);
break;
}
}
UINT8 CDSB1::IORead8(UINT32 addr)
{
int progress, end;
switch ((addr&0xFF))
{
case 0xE2: // MPEG position, high byte
MPEG_GetPlayPosition(&progress, &end);
progress += mpegStart; // byte address currently playing
return (progress>>16)&0xFF;
case 0xE3: // MPEG position, middle byte
MPEG_GetPlayPosition(&progress, &end);
progress += mpegStart;
return (progress>>8)&0xFF;
case 0xE4: // MPEG position, low byte
MPEG_GetPlayPosition(&progress, &end);
progress += mpegStart;
return progress&0xFF;
case 0xF0: // Latch
UINT8 d;
d = fifo[fifoIdxR]; // retrieve next command byte
if (fifoIdxR != fifoIdxW) // if these are equal, nothing has been written yet (don't advance)
{
fifoIdxR++;
fifoIdxR &= 127;
}
if (fifoIdxR == fifoIdxW) // FIFO empty?
status &= ~2; // yes, indicate no commands left
else
status |= 2;
Z80.SetINT(false); // clear IRQ
//printf("Z80: INT cleared, read from FIFO\n");
return d;
case 0xF1: // Status
/*
* Bit 0: Must be 1 for most games.
* Bit 1: Command pending (used by SWA instead of IRQ)
* SWA requires (status&0x38)==0 or else it loops endlessly
*/
return status;
}
//printf("Z80 Port Read %02X\n", addr);
return 0;
}
static int Z80IRQCallback(CZ80 *Z80)
{
return 0x38;
}
void CDSB1::SendCommand(UINT8 data)
{
/*
* Commands are buffered in a FIFO. This probably does not actually exist
* on the real DSB but is necessary because the Z80 is not really synced
* up with the other CPUs and must process all commands it has received
* over the course of a frame at once.
*/
fifo[fifoIdxW++] = data;
fifoIdxW &= 127;
//printf("Write FIFO: %02X\n", data);
// Have we caught up to the read pointer?
#ifdef DEBUG
if (fifoIdxW == fifoIdxR)
printf("DSB1 FIFO overflow!\n");
#endif
}
void CDSB1::RunFrame(INT16 *audioL, INT16 *audioR)
{
int cycles;
UINT8 v;
if (!m_config["EmulateDSB"].ValueAs())
{
// DSB code applies SCSP volume, too, so we must still mix
memset(mpegL, 0, (32000/60+2)*sizeof(INT16));
memset(mpegR, 0, (32000/60+2)*sizeof(INT16));
retainedSamples = Resampler.UpSampleAndMix(audioL, audioR, mpegL, mpegR, 0, 0, 44100/60, 32000/60+2, 44100, 32000);
return;
}
// While FIFO not empty, fire interrupts, run for up to one frame
for (cycles = (4000000/60)/4; (cycles > 0) && (fifoIdxR != fifoIdxW); )
{
Z80.SetINT(true); // fire an IRQ to indicate pending command
//printf("Z80 INT fired\n");
cycles -= Z80.Run(500);
}
// Run remaining cycles
Z80.Run(cycles);
//printf("VOLUME=%02X STEREO=%02X\n", volume, stereo);
// Convert volume from 0x00-0x7F -> 0x00-0xFF
v = (UINT8) ((float) 255.0f * (float) volume /127.0f);
// Decode MPEG for this frame
INT16 *mpegFill[2] = { &mpegL[retainedSamples], &mpegR[retainedSamples] };
MPEG_Decode(mpegFill, 32000/60-retainedSamples+2);
retainedSamples = Resampler.UpSampleAndMix(audioL, audioR, mpegL, mpegR, v, v, 44100/60, 32000/60+2, 44100, 32000);
}
void CDSB1::Reset(void)
{
MPEG_StopPlaying();
Resampler.Reset();
retainedSamples = 0;
memset(fifo, 0, sizeof(fifo));
fifoIdxW = fifoIdxR = 0;
status = 1;
mpegState = 0; // why doesn't RB ever init this?
volume = 0x7F; // full volume
usingLoopStart = 0;
// Even if DSB emulation is disabled, must reset to establish valid Z80 state
Z80.Reset();
DebugLog("DSB1 Reset\n");
}
void CDSB1::SaveState(CBlockFile *StateFile)
{
int i, j;
UINT32 playOffset, endOffset;
UINT8 isPlaying;
StateFile->NewBlock("DSB1", __FILE__);
// MPEG playback state
isPlaying = (UINT8) MPEG_IsPlaying();
MPEG_GetPlayPosition(&i, &j);
playOffset = (UINT32) i; // in case sizeof(int) != sizeof(INT32)
endOffset = (UINT32) j;
StateFile->Write(&isPlaying, sizeof(isPlaying));
StateFile->Write(&playOffset, sizeof(playOffset));
StateFile->Write(&endOffset, sizeof(endOffset));
StateFile->Write(&usingMPEGStart, sizeof(usingMPEGStart));
StateFile->Write(&usingMPEGEnd, sizeof(usingMPEGEnd));
StateFile->Write(&usingLoopStart, sizeof(usingLoopStart));
StateFile->Write(&usingLoopEnd, sizeof(usingLoopEnd));
// MPEG board state
StateFile->Write(ram, 0x8000);
StateFile->Write(fifo, sizeof(fifo));
StateFile->Write(&fifoIdxR, sizeof(fifoIdxR));
StateFile->Write(&fifoIdxW, sizeof(fifoIdxW));
StateFile->Write(&mpegStart, sizeof(mpegStart));
StateFile->Write(&mpegEnd, sizeof(mpegEnd));
StateFile->Write(&mpegState, sizeof(mpegState));
StateFile->Write(&loopStart, sizeof(loopStart));
StateFile->Write(&loopEnd, sizeof(loopEnd));
StateFile->Write(&status, sizeof(status));
StateFile->Write(&cmdLatch, sizeof(cmdLatch));
StateFile->Write(&volume, sizeof(volume));
StateFile->Write(&stereo, sizeof(stereo));
// Z80 CPU state
Z80.SaveState(StateFile, "DSB1 Z80");
}
void CDSB1::LoadState(CBlockFile *StateFile)
{
UINT32 playOffset, endOffset;
UINT8 isPlaying;
if (OKAY != StateFile->FindBlock("DSB1"))
{
ErrorLog("Unable to load Digital Sound Board state. Save state file is corrupt.");
return;
}
StateFile->Read(&isPlaying, sizeof(isPlaying));
StateFile->Read(&playOffset, sizeof(playOffset));
StateFile->Read(&endOffset, sizeof(endOffset));
StateFile->Read(&usingMPEGStart, sizeof(usingMPEGStart));
StateFile->Read(&usingMPEGEnd, sizeof(usingMPEGEnd));
StateFile->Read(&usingLoopStart, sizeof(usingLoopStart));
StateFile->Read(&usingLoopEnd, sizeof(usingLoopEnd));
StateFile->Read(ram, 0x8000);
StateFile->Read(fifo, sizeof(fifo));
StateFile->Read(&fifoIdxR, sizeof(fifoIdxR));
StateFile->Read(&fifoIdxW, sizeof(fifoIdxW));
StateFile->Read(&mpegStart, sizeof(mpegStart));
StateFile->Read(&mpegEnd, sizeof(mpegEnd));
StateFile->Read(&mpegState, sizeof(mpegState));
StateFile->Read(&loopStart, sizeof(loopStart));
StateFile->Read(&loopEnd, sizeof(loopEnd));
StateFile->Read(&status, sizeof(status));
StateFile->Read(&cmdLatch, sizeof(cmdLatch));
StateFile->Read(&volume, sizeof(volume));
StateFile->Read(&stereo, sizeof(stereo));
Z80.LoadState(StateFile, "DSB1 Z80");
// Restart MPEG audio at the appropriate position
if (isPlaying)
{
MPEG_PlayMemory((const char *) &mpegROM[usingMPEGStart], usingMPEGEnd-usingMPEGStart);
if (usingLoopEnd != 0) // only if looping was actually enabled
MPEG_SetLoop((const char *) &mpegROM[usingLoopStart], usingLoopEnd);
MPEG_SetPlayPosition(playOffset, endOffset);
}
else
MPEG_StopPlaying();
}
// Offsets of memory regions within DSB1's pool
#define DSB1_OFFSET_RAM 0 // 32KB Z80 RAM
#define DSB1_OFFSET_MPEG_LEFT 0x8000 // 1604 bytes (48 KHz max., 1/60th second, 2 extra = 2*(48000/60+2)) left MPEG buffer
#define DSB1_OFFSET_MPEG_RIGHT 0x8644 // 1604 bytes right MPEG buffer
#define DSB1_MEMORY_POOL_SIZE (0x8000 + 0x644 + 0x644)
bool CDSB1::Init(const UINT8 *progROMPtr, const UINT8 *mpegROMPtr)
{
float memSizeMB = (float)DSB1_MEMORY_POOL_SIZE/(float)0x100000;
// Receive ROM
progROM = progROMPtr;
mpegROM = mpegROMPtr;
// Allocate memory pool
memoryPool = new(std::nothrow) UINT8[DSB1_MEMORY_POOL_SIZE];
if (NULL == memoryPool)
return ErrorLog("Insufficient memory for DSB1 board (needs %1.1f MB).", memSizeMB);
memset(memoryPool, 0, DSB1_MEMORY_POOL_SIZE);
// Set up memory pointers
ram = &memoryPool[DSB1_OFFSET_RAM];
mpegL = (INT16 *) &memoryPool[DSB1_OFFSET_MPEG_LEFT];
mpegR = (INT16 *) &memoryPool[DSB1_OFFSET_MPEG_RIGHT];
// Initialize Z80 CPU
Z80.Init(this, Z80IRQCallback);
// MPEG decoder
if (OKAY != MPEG_Init())
return ErrorLog("Insufficient memory to initialize MPEG decoder.");
retainedSamples = 0;
return OKAY;
}
CZ80 *CDSB1::GetZ80(void)
{
return &Z80;
}
CDSB1::CDSB1(const Util::Config::Node &config)
: m_config(config),
Resampler(config)
{
progROM = NULL;
mpegROM = NULL;
memoryPool = NULL;
ram = NULL;
mpegL = NULL;
mpegR = NULL;
DebugLog("Built DSB1 Board\n");
}
CDSB1::~CDSB1(void)
{
MPEG_Shutdown();
if (memoryPool != NULL)
{
delete [] memoryPool;
memoryPool = NULL;
}
progROM = NULL;
mpegROM = NULL;
ram = NULL;
mpegL = NULL;
mpegR = NULL;
DebugLog("Destroyed DSB1 Board\n");
}
/******************************************************************************
Digital Sound Board Type 2: 68K CPU
******************************************************************************/
// MPEG state machine
enum
{
ST_IDLE = 0,
ST_GOT14, // start/loop addr
ST_14_0,
ST_14_1,
ST_GOT24, // end addr
ST_24_0,
ST_24_1,
ST_GOT74,
ST_GOTA0,
ST_GOTA1,
ST_GOTA3,
ST_GOTA4,
ST_GOTA5,
ST_GOTA7,
ST_GOTB0,
ST_GOTB1,
ST_GOTB2,
ST_GOTB4,
ST_GOTB5,
ST_GOTB6
};
static const char *stateName[] =
{
"idle",
"st_got_14",
"st_14_0",
"st_14_1",
"st_got24",
"st_24_0",
"st_24_1",
"st_got74",
"st_gota0",
"st_gota1",
"st_gota3",
"st_gota4",
"st_gota5",
"st_gota7",
"st_gotb0",
"st_gotb1",
"st_gotb2",
"st_gotb4",
"st_gotb5",
"st_gotb6"
};
void CDSB2::WriteMPEGFIFO(UINT8 byte)
{
//printf("fifo: %x (state %s)\n", byte, stateName[mpegState]);
switch (mpegState)
{
case ST_IDLE:
if (byte == 0x14) mpegState = ST_GOT14;
else if (byte == 0x15) mpegState = ST_GOT14;
else if (byte == 0x24) mpegState = ST_GOT24;
else if (byte == 0x25) mpegState = ST_GOT24;
else if (byte == 0x74 || byte == 0x75) // "start play"
{
usingLoopStart = 0;
usingLoopEnd = 0;
usingMPEGStart = mpegStart;
usingMPEGEnd = mpegEnd;
MPEG_PlayMemory((const char *) &mpegROM[mpegStart], mpegEnd-mpegStart);
//printf("playing %X\n", mpegStart);
mpegState = ST_IDLE;
playing = 1;
}
else if (byte == 0x84 || byte == 0x85)
{
MPEG_StopPlaying();
playing = 0;
}
else if (byte == 0xa0) mpegState = ST_GOTA0;
else if (byte == 0xa1) mpegState = ST_GOTA1;
else if (byte == 0xA3) mpegState = ST_GOTA3; // volume (front right?)
else if (byte == 0xa4) mpegState = ST_GOTA4;
else if (byte == 0xa5) mpegState = ST_GOTA5;
else if (byte == 0xA7) mpegState = ST_GOTA7; // volume (rear right?)
else if (byte == 0xb0) mpegState = ST_GOTB0;
else if (byte == 0xb1) mpegState = ST_GOTB1;
else if (byte == 0xB2) mpegState = ST_GOTB2; // volume (front left?)
else if (byte == 0xb4) mpegState = ST_GOTB4;
else if (byte == 0xb5) mpegState = ST_GOTB5;
else if (byte == 0xB6) mpegState = ST_GOTB6; // volume (rear left?)
break;
case ST_GOT14:
mpegStart &= 0x00FFFF;
mpegStart |= (byte<<16);
mpegState++;
break;
case ST_14_0:
mpegStart &= 0xFF00FF;
mpegStart |= (byte<<8);
mpegState++;
break;
case ST_14_1:
mpegStart &= 0xFFFF00;
mpegStart |= (byte);
mpegState = ST_IDLE;
if (playing)
{
//printf("Setting loop point to %x\n", mpegStart);
usingLoopStart = mpegStart;
usingLoopEnd = mpegEnd-mpegStart;
MPEG_SetLoop((const char *) &mpegROM[usingLoopStart], usingLoopEnd);
}
//printf("mpegStart=%x\n", mpegStart);
break;
case ST_GOT24:
mpegEnd &= 0x00FFFF;
mpegEnd |= (byte<<16);
mpegState++;
break;
case ST_24_0:
mpegEnd &= 0xFF00FF;
mpegEnd |= (byte<<8);
mpegState++;
break;
case ST_24_1:
mpegEnd &= 0xFFFF00;
mpegEnd |= (byte);
//printf("mpegEnd=%x\n", mpegEnd);
// default to full stereo
//mixer_set_stereo_volume(0, 255, 255);
//mixer_set_stereo_pan(0, MIXER_PAN_RIGHT, MIXER_PAN_LEFT);
stereo = StereoMode::Stereo;
mpegState = ST_IDLE;
break;
case ST_GOTA0:
// ch 0 mono
//mixer_set_stereo_volume(0, 0, 255);
//printf("ch 0 mono\n");
//mixer_set_stereo_pan(0, MIXER_PAN_CENTER, MIXER_PAN_CENTER);
stereo = (byte != 0x00) ? StereoMode::MonoRight : StereoMode::Stereo;
mpegState = ST_IDLE;
break;
case ST_GOTA4: // dayto2pe plays advertise tune from this state by writing 0x75
mpegState = ST_IDLE;
if (byte == 0x75)
{
usingLoopStart = 0;
usingLoopEnd = 0;
usingMPEGStart = mpegStart;
usingMPEGEnd = mpegEnd;
MPEG_PlayMemory((const char *) &mpegROM[mpegStart], mpegEnd-mpegStart);
//printf("playing %X (from st_gota4)\n", mpegStart);
playing = 1;
}
break;
case ST_GOTA5:
mpegState = ST_IDLE;
break;
case ST_GOTB1:
// ch 1 mono
//printf("ch 1 mono\n");
//mixer_set_stereo_volume(0, 255, 0);
//mixer_set_stereo_pan(0, MIXER_PAN_CENTER, MIXER_PAN_CENTER);
stereo = (byte != 0x00) ? StereoMode::MonoLeft : StereoMode::Stereo;
mpegState = ST_IDLE;
break;
case ST_GOTB4:
mpegState = ST_IDLE;
if (byte == 0x96)
{
MPEG_StopPlaying();
playing = 0;
}
break;
case ST_GOTB5:
mpegState = ST_IDLE;
break;
/*
* Speaker Volume:
*
* Daytona 2 uses B6, A7 for rear speakers; B2, A3 for front speakers.
*
* Star Wars Trilogy uses B0, A1 but B4, A4, B1, A1, B5, and A5 may be
* volume/speaker related.
*
* Sega Rally 2 uses B0, A0 and B4, A4 when setting all four but B0, A1
* when only setting two (in-game)
*/
case ST_GOTB6: // rear left(?) volume
volume[0] = byte;
mpegState = ST_IDLE;
break;
case ST_GOTB0: // left volume
volume[0] = byte;
//printf("Set L Volume: %02X\n", byte);
mpegState = ST_IDLE;
break;
case ST_GOTA7: // rear right(?) volume
volume[1] = byte;
mpegState = ST_IDLE;
break;
case ST_GOTA1: // right volume
volume[1] = byte;
mpegState = ST_IDLE;
break;
/*case ST_GOTA0:
volume[1] = byte;
//printf("Set R Volume: %02X\n", byte);
mpegState = ST_IDLE;
break;*/
case ST_GOTB2:
mpegState = ST_IDLE;
break;
case ST_GOTA3:
mpegState = ST_IDLE;
break;
default:
break;
}
}
UINT8 CDSB2::Read8(UINT32 addr)
{
if (addr < (128*1024))
return progROM[addr^1];
if (addr == 0xc00001)
{
return cmdLatch;
}
if (addr == 0xc00003) // bit 0 = command valid
{
return 1;
}
if (addr == 0xe80001)
{
return 0x01; // MPEG busy status: bit 1 = busy
} // polled by irq2, stored | 0x10 at f01010
if ((addr >= 0xf00000) && (addr < 0xf10000))
{
addr &= 0x1ffff;
return ram[addr^1];
}
//printf("R8 @ %x\n", addr);
return 0;
}
UINT16 CDSB2::Read16(UINT32 addr)
{
if (addr < (128*1024))
{
return *(UINT16 *) &progROM[addr];
}
if ((addr >= 0xf00000) && (addr < 0xf20000))
{
addr &= 0x1ffff;
return *(UINT16 *) &ram[addr];
}
//printf("R16 @ %x\n", addr);
return 0;
}
UINT32 CDSB2::Read32(UINT32 addr)
{
UINT32 hi, lo;
if (addr < (128*1024))
{
hi = *(UINT16 *) &progROM[addr];
lo = *(UINT16 *) &progROM[addr+2];
return (hi<<16)|lo;
}
if ((addr >= 0xf00000) && (addr < 0xf20000))
{
addr &= 0x1ffff;
hi = *(UINT16 *) &ram[addr];
lo = *(UINT16 *) &ram[addr+2];
return (hi<<16)|lo;
}
//printf("R32 @ %x\n", addr);
return 0;
}
void CDSB2::Write8(UINT32 addr, UINT8 data)
{
if ((addr >= 0xf00000) && (addr < 0xf20000))
{
addr &= 0x1ffff;
ram[addr^1] = data;
return;
}
if (addr == 0xd00001) return;
if (addr == 0xe00003)
{
WriteMPEGFIFO(data);
return;
}
//printf("W8: %x @ %x (PC=%x)\n", data, addr, m68k_get_reg(NULL, M68K_REG_PC));
}
void CDSB2::Write16(UINT32 addr, UINT16 data)
{
if ((addr >= 0xf00000) && (addr < 0xf20000))
{
addr &= 0x1ffff;
*(UINT16 *) &ram[addr] = data;
return;
}
//printf("W16: %x @ %x\n", data, addr);
}
void CDSB2::Write32(UINT32 addr, UINT32 data)
{
if ((addr >= 0xf00000) && (addr < 0xf20000))
{
addr &= 0x1ffff;
*(UINT16 *) &ram[addr+0] = (data>>16);
*(UINT16 *) &ram[addr+2] = data&0xFFFF;
return;
}
//printf("W32: %x @ %x\n", data, addr);
}
void CDSB2::SendCommand(UINT8 data)
{
/*
* Commands are buffered in a FIFO. This probably does not actually exist
* on the real DSB but is necessary because the 68K is not really synced
* up with the other CPUs and must process all commands it has received
* over the course of a frame at once.
*/
fifo[fifoIdxW++] = data;
fifoIdxW &= 127;
//printf("Write FIFO: %02X\n", data);
// Have we caught up to the read pointer?
#ifdef DEBUG
if (fifoIdxW == fifoIdxR)
printf("DSB2 FIFO overflow!\n");
#endif
}
void CDSB2::RunFrame(INT16 *audioL, INT16 *audioR)
{
if (!m_config["EmulateDSB"].ValueAs())
{
// DSB code applies SCSP volume, too, so we must still mix
memset(mpegL, 0, (32000/60+2)*sizeof(INT16));
memset(mpegR, 0, (32000/60+2)*sizeof(INT16));
retainedSamples = Resampler.UpSampleAndMix(audioL, audioR, mpegL, mpegR, volume[0], volume[1], 44100/60, 32000/60+2, 44100, 32000);
return;
}
M68KSetContext(&M68K);
//printf("DSB2 run frame PC=%06X\n", M68KGetPC());
// While FIFO not empty...
while (fifoIdxR != fifoIdxW)
{
cmdLatch = fifo[fifoIdxR]; // retrieve next command byte
fifoIdxR++;
fifoIdxR &= 127;
M68KSetIRQ(1); // indicate pending command
//printf("68K INT fired\n");
M68KRun(500);
}
// Per-frame interrupt
M68KSetIRQ(2);
M68KRun(4000000/60);
M68KGetContext(&M68K);
// Decode MPEG for this frame
INT16 *mpegFill[2] = { &mpegL[retainedSamples], &mpegR[retainedSamples] };
MPEG_Decode(mpegFill, 32000/60-retainedSamples+2);
INT16 *leftChannelSource = nullptr;
INT16 *rightChannelSource = nullptr;
UINT8 volL=0, volR=0;
switch (stereo)
{
default:
case StereoMode::Stereo:
leftChannelSource = mpegL;
rightChannelSource = mpegR;
volL = volume[0];
volR = volume[1];
break;
case StereoMode::MonoLeft:
leftChannelSource = mpegL;
rightChannelSource = mpegL;
volL = volume[1];
volR = volume[1];
break;
case StereoMode::MonoRight:
leftChannelSource = mpegR;
rightChannelSource = mpegR;
volL = volume[0];
volR = volume[0];
break;
}
retainedSamples = Resampler.UpSampleAndMix(audioL, audioR, leftChannelSource, rightChannelSource, volL, volR, 44100/60, 32000/60+2, 44100, 32000);
}
void CDSB2::Reset(void)
{
MPEG_StopPlaying();
Resampler.Reset();
retainedSamples = 0;
memset(fifo, 0, sizeof(fifo));
fifoIdxW = fifoIdxR = 0;
mpegState = ST_IDLE;
mpegStart = 0;
mpegEnd = 0;
playing = 0;
volume[0] = 0xFF; // set to max volume in case we miss the volume commands
volume[1] = 0xFF;
stereo = StereoMode::Stereo;
// Even if DSB emulation is disabled, must reset to establish valid Z80 state
M68KSetContext(&M68K);
M68KReset();
//printf("DSB2 PC=%06X\n", M68KGetPC());
M68KGetContext(&M68K);
DebugLog("DSB2 Reset\n");
}
void CDSB2::SaveState(CBlockFile *StateFile)
{
int i, j;
UINT32 playOffset, endOffset;
UINT8 isPlaying;
StateFile->NewBlock("DSB2", __FILE__);
// MPEG playback state
isPlaying = (UINT8) MPEG_IsPlaying();
MPEG_GetPlayPosition(&i, &j);
playOffset = (UINT32) i; // in case sizeof(int) != sizeof(INT32)
endOffset = (UINT32) j;
StateFile->Write(&isPlaying, sizeof(isPlaying));
StateFile->Write(&playOffset, sizeof(playOffset));
StateFile->Write(&endOffset, sizeof(endOffset));
StateFile->Write(&usingMPEGStart, sizeof(usingMPEGStart));
StateFile->Write(&usingMPEGEnd, sizeof(usingMPEGEnd));
StateFile->Write(&usingLoopStart, sizeof(usingLoopStart));
StateFile->Write(&usingLoopEnd, sizeof(usingLoopEnd));
// MPEG board state
StateFile->Write(ram, 0x20000);
StateFile->Write(fifo, sizeof(fifo));
StateFile->Write(&fifoIdxR, sizeof(fifoIdxR));
StateFile->Write(&fifoIdxW, sizeof(fifoIdxW));
StateFile->Write(&cmdLatch, sizeof(cmdLatch));
StateFile->Write(&mpegState, sizeof(mpegState));
StateFile->Write(&mpegStart, sizeof(mpegStart));
StateFile->Write(&mpegEnd, sizeof(mpegEnd));
StateFile->Write(&playing, sizeof(playing));
StateFile->Write(volume, sizeof(volume));
StateFile->Write(&stereo, sizeof(stereo));
// 68K CPU state
M68KSetContext(&M68K);
M68KSaveState(StateFile, "DSB2 68K");
//DEBUG
//printf("DSB2 PC=%06X\n", M68KGetPC());
//printf("mpegStart=%X, mpegEnd=%X\n", mpegStart, mpegEnd);
//printf("usingMPEGStart=%X, usingMPEGEnd=%X\n", usingMPEGStart, usingMPEGEnd);
//printf("usingLoopStart=%X, usingLoopEnd=%X\n", usingLoopStart, usingLoopEnd);
}
void CDSB2::LoadState(CBlockFile *StateFile)
{
UINT32 playOffset, endOffset;
UINT8 isPlaying;
if (OKAY != StateFile->FindBlock("DSB2"))
{
ErrorLog("Unable to load Digital Sound Board state. Save state file is corrupt.");
return;
}
StateFile->Read(&isPlaying, sizeof(isPlaying));
StateFile->Read(&playOffset, sizeof(playOffset));
StateFile->Read(&endOffset, sizeof(endOffset));
StateFile->Read(&usingMPEGStart, sizeof(usingMPEGStart));
StateFile->Read(&usingMPEGEnd, sizeof(usingMPEGEnd));
StateFile->Read(&usingLoopStart, sizeof(usingLoopStart));
StateFile->Read(&usingLoopEnd, sizeof(usingLoopEnd));
StateFile->Read(ram, 0x20000);
StateFile->Read(fifo, sizeof(fifo));
StateFile->Read(&fifoIdxR, sizeof(fifoIdxR));
StateFile->Read(&fifoIdxW, sizeof(fifoIdxW));
StateFile->Read(&cmdLatch, sizeof(cmdLatch));
StateFile->Read(&mpegState, sizeof(mpegState));
StateFile->Read(&mpegStart, sizeof(mpegStart));
StateFile->Read(&mpegEnd, sizeof(mpegEnd));
StateFile->Read(&playing, sizeof(playing));
StateFile->Read(volume, sizeof(volume));
StateFile->Read(&stereo, sizeof(stereo));
M68KSetContext(&M68K);
M68KLoadState(StateFile, "DSB2 68K");
M68KGetContext(&M68K);
// Restart MPEG audio at the appropriate position
if (isPlaying)
{
MPEG_PlayMemory((const char *) &mpegROM[usingMPEGStart], usingMPEGEnd-usingMPEGStart);
if (usingLoopEnd != 0) // only if looping was actually enabled
MPEG_SetLoop((const char *) &mpegROM[usingLoopStart], usingLoopEnd);
MPEG_SetPlayPosition(playOffset, endOffset);
}
else
MPEG_StopPlaying();
//DEBUG
//printf("DSB2 PC=%06X\n", M68KGetPC());
//printf("mpegStart=%X, mpegEnd=%X\n", mpegStart, mpegEnd);
//printf("usingMPEGStart=%X, usingMPEGEnd=%X\n", usingMPEGStart, usingMPEGEnd);
//printf("usingLoopStart=%X, usingLoopEnd=%X\n", usingLoopStart, usingLoopEnd);
}
// Offsets of memory regions within DSB2's pool
#define DSB2_OFFSET_RAM 0 // 128KB 68K RAM
#define DSB2_OFFSET_MPEG_LEFT 0x20000 // 1604 bytes (48 KHz max., 1/60th second, 2 extra = 2*(48000/60+2)) left MPEG buffer
#define DSB2_OFFSET_MPEG_RIGHT 0x20644 // 1604 bytes right MPEG buffer
#define DSB2_MEMORY_POOL_SIZE (0x20000 + 0x644 + 0x644)
bool CDSB2::Init(const UINT8 *progROMPtr, const UINT8 *mpegROMPtr)
{
float memSizeMB = (float)DSB2_MEMORY_POOL_SIZE/(float)0x100000;
// Receive ROM
progROM = progROMPtr;
mpegROM = mpegROMPtr;
// Allocate memory pool
memoryPool = new(std::nothrow) UINT8[DSB2_MEMORY_POOL_SIZE];
if (NULL == memoryPool)
return ErrorLog("Insufficient memory for DSB2 board (needs %1.1f MB).", memSizeMB);
memset(memoryPool, 0, DSB2_MEMORY_POOL_SIZE);
// Set up memory pointers
ram = &memoryPool[DSB2_OFFSET_RAM];
mpegL = (INT16 *) &memoryPool[DSB2_OFFSET_MPEG_LEFT];
mpegR = (INT16 *) &memoryPool[DSB2_OFFSET_MPEG_RIGHT];
// Initialize 68K CPU
M68KSetContext(&M68K);
M68KInit();
M68KAttachBus(this);
M68KSetIRQCallback(NULL); // use default behavior (autovector, clear interrupt)
M68KGetContext(&M68K);
// MPEG decoder
if (OKAY != MPEG_Init())
return ErrorLog("Insufficient memory to initialize MPEG decoder.");
retainedSamples = 0;
return OKAY;
}
M68KCtx *CDSB2::GetM68K(void)
{
return &M68K;
}
CDSB2::CDSB2(const Util::Config::Node &config)
: m_config(config),
Resampler(config)
{
progROM = NULL;
mpegROM = NULL;
memoryPool = NULL;
ram = NULL;
mpegL = NULL;
mpegR = NULL;
DebugLog("Built DSB2 Board\n");
}
CDSB2::~CDSB2(void)
{
MPEG_Shutdown();
if (memoryPool != NULL)
{
delete [] memoryPool;
memoryPool = NULL;
}
progROM = NULL;
mpegROM = NULL;
ram = NULL;
mpegL = NULL;
mpegR = NULL;
DebugLog("Destroyed DSB2 Board\n");
}