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rework noise readout, alter noise freq for specific feedback bits config

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LTVA1 2024-08-17 13:40:15 +03:00
parent 4079f7a8c3
commit 80933510a5
3 changed files with 61 additions and 17 deletions
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35
src/engine/platform/sid3.cpp
View file

@ -72,6 +72,19 @@ const char* regCheatSheetSID3[]={
NULL
};
typedef struct
{
uint32_t LFSRmask;
float freqScaling;
} noiseFreqData;
const noiseFreqData noiseInterestingWavesData[] =
{
{524288, 523.0f / 1675.0f}, //wave very close to SID2 noise mode 1 wave
{0, 0.0f}, //end marker
};
const char** DivPlatformSID3::getRegisterSheet() {
return regCheatSheetSID3;
}
@ -490,6 +503,7 @@ void DivPlatformSID3::tick(bool sysTick)
if (chan[i].std.ex7.had) { //noise LFSR feedback bits
chan[i].noiseLFSRMask = chan[i].std.ex7.val & 0x3fffffff;
updateNoiseLFSRMask(i);
chan[i].noiseFreqChanged = true;
}
if (chan[i].std.op[1].ar.had) { //1-bit noise / PCM mode for wavetable chan
if(i == SID3_NUM_CHANNELS - 1) //wave chan
@ -714,15 +728,27 @@ void DivPlatformSID3::tick(bool sysTick)
if(chan[i].independentNoiseFreq)
{
chan[i].noiseFreq=parent->calcFreq(chan[i].baseFreq,chan[i].pitch,chan[i].noise_fixedArp?chan[i].noise_baseNoteOverride:chan[i].noise_arpOff,chan[i].noise_fixedArp,false,2,chan[i].noise_pitch2,chipClock,CHIP_FREQBASE * 64);
if (chan[i].noiseFreq<0) chan[i].noiseFreq=0;
if (chan[i].noiseFreq>0xffffff) chan[i].noiseFreq=0xffffff;
}
else
{
chan[i].noiseFreq = chan[i].freq;
}
bool found = false;
int index = 0;
while(noiseInterestingWavesData != 0 && !found)
{
if(noiseInterestingWavesData[index].LFSRmask == chan[i].noiseLFSRMask)
{
chan[i].noiseFreq *= noiseInterestingWavesData[index].freqScaling;
found = true;
}
index++;
}
if (chan[i].noiseFreq<0) chan[i].noiseFreq=0;
if (chan[i].noiseFreq>0xffffff) chan[i].noiseFreq=0xffffff;
updateNoiseFreq(i);
chan[i].noiseFreqChanged = false;
@ -1052,6 +1078,7 @@ int DivPlatformSID3::dispatch(DivCommand c) {
chan[c.chan].noiseLFSRMask &= ~(0xffU << (8 * c.value2));
chan[c.chan].noiseLFSRMask |= ((c.value & (c.value2 == 3 ? 0x3f : 0xff)) << (8 * c.value2));
updateNoiseLFSRMask(c.chan);
chan[c.chan].noiseFreqChanged = true;
break;
case DIV_CMD_SID3_1_BIT_NOISE:
if(c.chan == SID3_NUM_CHANNELS - 1) //wave chan
@ -1250,7 +1277,7 @@ void DivPlatformSID3::reset() {
chan[i].freq = chan[i].noiseFreq = 0;
updatePanning(i);
chan[i].noiseLFSRMask = (1 << 29) | (1 << 5) | (1 << 3) | 1; //https://docs.amd.com/v/u/en-US/xapp052 for 30 bits: 30, 6, 4, 1
chan[i].noiseLFSRMask = 1 | (1 << 23) | (1 << 25) | (1 << 29); //https://docs.amd.com/v/u/en-US/xapp052 for 30 bits: 30, 6, 4, 1; but inverted since our LFSR is moving in different direction
chan[i].pw_slide = 0;

21
src/engine/platform/sound/sid3.c
View file

@ -2254,7 +2254,16 @@ void sid3_clock_lfsr(sid3_channel* ch)
uint16_t sid3_noise(uint32_t lfsr, bool one_bit)
{
return one_bit ? ((lfsr & 1) ? 0xffff : 0) : (lfsr & 0xffff);
return one_bit ? ((lfsr & 1) ? 0xffff : 0) :
((((lfsr & 1) << 7) |
((lfsr & 4) << 4) |
((lfsr & 0x40) >> 1) |
((lfsr & 0x200) >> 5) |
((lfsr & 0x800) >> 8) |
((lfsr & 0x8000) >> 13) |
((lfsr & 0x40000) >> 17) |
((lfsr & 0x100000) >> 20)) << 8); //bits like in SID
}
uint16_t sid3_special_wave(SID3* sid3, uint32_t acc, uint8_t wave)
@ -2353,8 +2362,8 @@ void sid3_reset(SID3* sid3)
{
memset(&sid3->chan[i], 0, sizeof(sid3_channel));
sid3->chan[i].adsr.hold_zero = true;
sid3->chan[i].lfsr = 0x1;
sid3->chan[i].lfsr_taps = (1 << 29) | (1 << 5) | (1 << 3) | 1; //https://docs.amd.com/v/u/en-US/xapp052 for 30 bits: 30, 6, 4, 1
sid3->chan[i].lfsr = 0x0ffffff; //three MSBs are left as 0
sid3->chan[i].lfsr_taps = 1 | (1 << 23) | (1 << 25) | (1 << 29); //https://docs.amd.com/v/u/en-US/xapp052 for 30 bits: 30, 6, 4, 1; but inverted since our LFSR is moving in different direction
for(int j = 0; j < SID3_NUM_FILTERS; j++)
{
@ -3044,7 +3053,7 @@ void sid3_clock(SID3* sid3)
{
ch->accumulator = 0;
ch->noise_accumulator = 0;
ch->lfsr = 0x1;
ch->lfsr = 0x0fffffff; //three MSBs are left as 0
}
}
else
@ -3053,7 +3062,7 @@ void sid3_clock(SID3* sid3)
{
ch->accumulator = 0;
ch->noise_accumulator = 0;
ch->lfsr = 0x1;
ch->lfsr = 0x0fffffff; //three MSBs are left as 0
}
}
}
@ -3315,7 +3324,7 @@ void sid3_write(SID3* sid3, uint16_t address, uint8_t data)
if(sid3->chan[channel].flags & SID3_CHAN_NOISE_PHASE_RESET)
{
sid3->chan[channel].noise_accumulator = 0;
sid3->chan[channel].lfsr = 0x1;
sid3->chan[channel].lfsr = 0x0fffffff; //three MSBs are left as 0
}
sid3->chan[channel].flags &= ~(SID3_CHAN_ENV_RESET | SID3_CHAN_NOISE_PHASE_RESET | SID3_CHAN_PHASE_RESET);