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Tedsound.cpp
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Tedsound.cpp
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#include "Audio.h"
#include "Tedmem.h"
#include "Filter.h"
#include <math.h>
#ifdef _DEBUG
#include <cstdio>
#endif
#define PRECISION 0
#define OSCRELOADVAL (0x400 << PRECISION)
#define AMP(X) ((unsigned int)(17.0f * pow(double(X), 1.5f)))
unsigned int TED::masterVolume;
static int Volume;
static int Snd1Status;
static int Snd2Status;
static int SndNoiseStatus;
static int DAStatus;
static unsigned short Freq1;
static unsigned short Freq2;
static int NoiseCounter;
static int FlipFlop[2];
static int dcOutput[2];
static int oscCount[2];
static int OscReload[2];
static int oscStep;
static unsigned char noise[256]; // 0-8
static int volumeTable[64];
inline void TED::setFreq(unsigned int channel, int freq)
{
dcOutput[channel] = (freq == 0x3FE) ? 1 : 0;
OscReload[channel] = ((freq + 1)&0x3FF) << PRECISION;
}
void TED::oscillatorReset()
{
FlipFlop[0] = dcOutput[0] = 0;
FlipFlop[1] = dcOutput[1] = 0;
oscCount[0] = 0;
oscCount[1] = 0;
NoiseCounter = 0;
Freq1 = Freq2 = 0;
DAStatus = Snd1Status = Snd2Status = SndNoiseStatus = 0;
}
// call only once!
void TED::oscillatorInit()
{
unsigned int i;
oscillatorReset();
int im = 0xff;
for (i = 0; i < 256; i++) {
im = (im << 1) | (((im >> 7) ^ (im >> 5) ^ (im >> 4) ^ (im >> 1)) & 1);
noise[i] = im & 1;
}
for (i = 0; i < 64; i++) {
int chdbl = (i & 0x30) == 0x30;
int vol = ((i & 0x0F) < 9 ? (i & 0x0F) : 8);
int nonl = ((chdbl && vol > 1) ? vol * vol * 54 - 173 * vol + 162 : 0);
volumeTable[i] = (vol && i & 0x30) ?
(nonl + (586 + (vol - 1) * 1024) << (chdbl ? 1 : 0)) : 0;
}
oscStep = (1 << PRECISION) << 0;
// set player specific parameters
waveForm[0] = waveForm[1] = 1;
masterVolume = AMP(8);
setplaybackSpeed(3);
enableChannel(0, true);
enableChannel(1, true);
enableChannel(2, true);
}
void TED::writeSoundReg(unsigned int reg, unsigned char value)
{
#if defined(_DEBUG) && 0
static FILE *f = std::fopen("freqlog.txt", "a");
if (f)
std::fprintf(f, "%04X <- %02X in cycle %llu", 0xff0e + reg, value, CycleCounter);
fprintf(f, "\n");
#endif
switch (reg) {
case 0:
Freq1 = (Freq1 & 0x300) | value;
setFreq(0, Freq1);
break;
case 1:
Freq2 = (Freq2 & 0x300) | value;
setFreq(1, Freq2);
break;
case 2:
Freq2 = (Freq2 & 0xFF) | (value << 8);
setFreq(1, Freq2);
break;
case 3:
if ((DAStatus = value & 0x80)) {
FlipFlop[0] = 1;
FlipFlop[1] = 1;
oscCount[0] = OscReload[0];
oscCount[1] = OscReload[1];
NoiseCounter = 0;
}
Volume = value & 0x0F;
if (Volume > 8) Volume = 8;
Volume = (Volume << 9);
Snd1Status = value & 0x10;
Snd2Status = value & 0x20;
SndNoiseStatus = value & 0x40;
break;
case 4:
Freq1 = (Freq1 & 0xFF) | (value << 8);
setFreq(0, Freq1);
break;
}
}
void TED::storeToBuffer(short *buffer, unsigned int count)
{
static double lp_accu = 0;
static double hp_accu = 0;
const double hptc = 20000.0/1000000; // 6000us (est) maybe 7000 ?
const double hpc = 1.0/(hptc * sampleRate * 2.0); // 2*pi*fc=1/tau..
// TODO: a proper windowed lowpass FIR filter
#if 0
const double lpc = 1.0 - exp( - double(sampleRate) / 2.0 / double(TED_SOUND_CLOCK));
do {
double accu = (double) *buffer;
// apply low pass filter -> lp_accu = lpc*accu + (1-lpc)*lp_accu
lp_accu += lpc * (accu - lp_accu);
accu = lp_accu - hp_accu;
// update hp filter pole
hp_accu += hpc * accu;
// fill the buffer
*buffer++ = ((short)accu);
} while(--count);
#else
do {
double accu = (double) filter->lowPass(*buffer);
accu = accu - hp_accu;
// update hp filter pole
hp_accu += hpc * accu;
// fill the buffer
*buffer++ = (short)accu;
} while(--count);
#endif
}
inline unsigned int TED::waveSquare(unsigned int channel)
{
return Volume;
}
inline unsigned int TED::waveSawTooth(unsigned int channel)
{
unsigned int mod;
#if 0
int msb = OSCRELOADVAL + 1 - OscReload[channel];
int diff = 2 * msb - int(FlipFlop[channel]) * msb - int(oscCount[channel]) + int(OscReload[channel]);
//if (diff < 0) diff = 0;
//if (oscCount[channel] >= 0x3fa) diff = 0;
mod = (Volume * diff) / (2 * msb);
#else
int diff = int(oscCount[channel]) - int(OscReload[channel]);
if (diff < 0) diff = 0;
mod = (Volume * diff) / (OSCRELOADVAL + 1 - OscReload[channel]);
#endif
return mod;
}
inline unsigned int TED::waveTriangle(unsigned int channel)
{
unsigned int mod;
int msb;
#if 0
msb = OSCRELOADVAL + 1 - OscReload[channel];
int diff = FlipFlop[channel] ? int(oscCount[channel]) - int(OscReload[channel])
: int(OSCRELOADVAL) - int(oscCount[channel]);
//if (diff < 0) diff = 0;
//if (oscCount[channel] >= 0x3fa) diff = 0;
mod = (3 * Volume * diff / msb / 2);
#else
/*
msb = (OscReload[channel] + OSCRELOADVAL) / 2;
int diff = oscCount[channel] < msb ? oscCount[channel] - OscReload[channel] : OSCRELOADVAL - oscCount[channel];
mod = (2 * diff * Volume / (OSCRELOADVAL - OscReload[channel] + 1));
if (mod > Volume) mod = Volume;
*/
msb = (OscReload[channel] + OSCRELOADVAL) / 2;
mod = oscCount[channel] < msb ? oscCount[channel] : (oscCount[channel] - msb);
mod = (mod * Volume / msb);
#endif
return mod;
}
inline unsigned int TED::getWaveSample(unsigned int channel, unsigned int wave)
{
unsigned int sm;
switch (wave) {
default:
case 1: // square
return waveSquare(channel);
case 2: // sawtooth
return waveSawTooth(channel);
case 4: // triangle
return waveTriangle(channel);
// combined waveforms á la SID
case 3: // square + sawtooth
sm = waveSawTooth(channel) + waveSquare(channel);
return sm /= 2;
case 5: // square + triangle
sm = waveTriangle(channel) + waveSquare(channel);
return sm /= 2;
case 6: // sawtooth + triangle
sm = waveTriangle(channel) + waveSawTooth(channel);
return sm /= 2;
case 7: // square + sawtooth + triangle
sm = waveTriangle(channel) + waveSawTooth(channel) + waveSquare(channel);
return sm /= 3;
}
}
void TED::renderSound(unsigned int nrsamples, short *buffer)
{
// Calculate the buffer...
if (DAStatus) {// digi?
int sample = (volumeTable[Snd1Status | Snd2Status | (Volume >> 9)] & channelMask[2]) * masterVolume / 1000;
for (;nrsamples--;) {
*buffer++ = short(sample);
}
} else {
unsigned int result;
for (;nrsamples--;) {
// Channel 1
if (dcOutput[0]) {
FlipFlop[0] = 1;
} else if ((oscCount[0] += oscStep) >= OSCRELOADVAL) {
FlipFlop[0] ^= 1;
oscCount[0] = OscReload[0] + (oscCount[0] - OSCRELOADVAL);
}
// Channel 2
static bool channelOverFlow = false;
if (dcOutput[1]) {
FlipFlop[1] = 1;
}
else {
if (channelOverFlow)
NoiseCounter = (NoiseCounter + 1) % 255;
if ((oscCount[1] += oscStep) >= OSCRELOADVAL) {
channelOverFlow = true;
FlipFlop[1] ^= 1;
oscCount[1] = OscReload[1] + (oscCount[1] - OSCRELOADVAL);
}
else
channelOverFlow = false;
}
int s1on = (Snd1Status && FlipFlop[0]);
int s2on = (Snd2Status && FlipFlop[1]);
int non = SndNoiseStatus && noise[NoiseCounter];
result = s1on ? (getWaveSample(0, waveForm[0]) & channelMask[0]) : 0;
if (s2on) {
result += getWaveSample(1, waveForm[1]) & channelMask[1];
} else if (non) {
result += volumeTable[0x20 | (Volume >> 9)] & channelMask[2];
}
if ((s2on || non) && s1on && Volume) {
unsigned int vol = Volume >> 9;
result = (result * volumeTable[0x30 | vol]) / (volumeTable[0x10 | vol] * 2);
}
*buffer++ = result * masterVolume / 1000;
} // for
}
}
void TED::setMasterVolume(unsigned int shift)
{
if (!shift)
masterVolume = 0;
else
masterVolume = AMP(shift);
}
void TED::selectWaveForm(unsigned int channel, unsigned int wave)
{
waveForm[channel] = wave;
}
void TED::setplaybackSpeed(unsigned int speed)
{
unsigned int speeds[] = { 16, 8, 4, 3, 2 };
playbackSpeed = speeds[(speed - 1) % sizeof(speeds)];
}
unsigned int TED::getTimeSinceLastReset()
{
ClockCycle elapsedCycles = CycleCounter - lastResetCycle;
unsigned int secondsPlayed = (unsigned int)(double(elapsedCycles) / double(TED_SOUND_CLOCK * 4) + 0.5);
return secondsPlayed;
}
void TED::setSampleRate(unsigned int value)
{
initFilter(value, filterOrder);
}
void TED::setFilterOrder(unsigned int value)
{
initFilter(sampleRate, value);
}
void TED::initFilter(unsigned int sampleRate_, unsigned int filterOrder_)
{
if (filter)
delete filter;
filter = new Filter(sampleRate_ / 2, TED_SOUND_CLOCK, filterOrder_);
filter->reCalcWindowTable();
filterOrder = filterOrder_;
sampleRate = sampleRate_;
}