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updated fds audio code to be more in line with whats currently known …
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@FIX94
FIX94 committed Feb 2, 2020
1 parent edc3636 commit 2b6535d
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Showing 2 changed files with 90 additions and 102 deletions.
190 changes: 89 additions & 101 deletions audio_fds.c
View file
Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
/*
* Copyright (C) 2017 - 2018 FIX94
* Copyright (C) 2017 - 2020 FIX94
*
* This software may be modified and distributed under the terms
* of the MIT license. See the LICENSE file for details.
Expand All @@ -23,48 +23,50 @@ uint8_t fdsOut;

static struct {
uint8_t wave[0x40];
uint8_t modulation[0x40];
uint8_t curWavePos, curModPos;
uint8_t modulation[0x20];
uint8_t curModPos;
uint8_t curWave;
uint8_t envSpeed;
uint8_t volEnvSpeed, volEnvGain, volEnvMode;
uint8_t sweepSpeed, sweepModGain, sweepMode;
uint8_t envSpeed, volEnvSpeed, sweepSpeed;
uint8_t volEnvGain, volEnvMode;
uint8_t sweepModGain, sweepMode;
uint8_t masterVol;
uint8_t tickCnt;
int8_t modCounter;
uint16_t freq, modFreq;
int16_t modChange;
uint32_t curMasterClock, curModClock, curVolEnvClock, curSweepClock;
uint32_t volEnvClock, sweepClock;
uint32_t curMasterClock;
uint16_t curModClock;
uint32_t volEnvClock, sweepClock, curVolEnvClock, curSweepClock;
bool masterEnable;
bool volEnvEnabled;
bool envMasterEnable;
bool sweepEnabled;
bool modEnabled;
bool modForce;
bool wavWrite;
} fds_apu;

static void fdsUpdateClockRates()
{
fds_apu.volEnvClock = 8 * fds_apu.envSpeed * (fds_apu.volEnvSpeed + 1);
fds_apu.sweepClock = 8 * fds_apu.envSpeed * (fds_apu.sweepSpeed + 1);
fds_apu.volEnvClock = 8 * (fds_apu.envSpeed + 1) * (fds_apu.volEnvSpeed + 1);
fds_apu.sweepClock = 8 * (fds_apu.envSpeed + 1) * (fds_apu.sweepSpeed + 1);
}

void fdsAudioInit()
{
memset(fds_apu.wave, 0, 0x40);
memset(fds_apu.modulation, 0, 0x40);
memset(fds_apu.modulation, 0, 0x20);
audioExpansion |= EXP_FDS;
fdsOut = 0;
fds_apu.curWavePos = 0, fds_apu.curModPos = 0;
fds_apu.curModPos = 0;
fds_apu.curWave = 0;
fds_apu.envSpeed = 0xE8; //from FDS BIOS
fds_apu.volEnvSpeed = 0, fds_apu.volEnvGain = 0, fds_apu.volEnvMode = 0;
fds_apu.sweepSpeed = 0, fds_apu.sweepModGain = 0, fds_apu.sweepMode = 0;
fdsUpdateClockRates();
fds_apu.masterVol = 0;
fds_apu.tickCnt = 0;
fds_apu.modCounter = 0;
fds_apu.freq = 0, fds_apu.modFreq = 0;
fds_apu.modChange = 0;
fds_apu.curMasterClock = 0;
fds_apu.curModClock = 0;
fds_apu.curVolEnvClock = fds_apu.volEnvClock;
Expand All @@ -74,6 +76,7 @@ void fdsAudioInit()
fds_apu.envMasterEnable = false;
fds_apu.sweepEnabled = false;
fds_apu.modEnabled = false;
fds_apu.modForce = false;
fds_apu.wavWrite = false;
}

Expand All @@ -94,11 +97,8 @@ FIXNES_NOINLINE void fdsAudioCycle()
fdsOut = (tmp>>5)&0x3F;
}

void fdsAudioClockTimers()
static void fdsDoEnv()
{
if(!fds_apu.masterEnable || !fds_apu.envMasterEnable)
return;

if(fds_apu.volEnvEnabled)
{
if(fds_apu.curVolEnvClock)
Expand Down Expand Up @@ -142,88 +142,82 @@ void fdsAudioClockTimers()
}
}

FIXNES_NOINLINE void fdsAudioMasterUpdate()
void fdsAudioClockTimers()
{
if(fds_apu.masterEnable)
if(!fds_apu.envMasterEnable || !fds_apu.envSpeed)
return;
fdsDoEnv();
//when master is off but envs on, envs runs 4x faster
if(!fds_apu.masterEnable)
{
fds_apu.curMasterClock += (fds_apu.freq + fds_apu.modChange);
if(fds_apu.curMasterClock&(~0xFFFF))
{
fds_apu.curMasterClock &= 0xFFFF;
//do master stuff
fds_apu.curWave = fds_apu.wave[fds_apu.curWavePos];
fds_apu.curWavePos++;
if(fds_apu.curWavePos >= 0x40)
fds_apu.curWavePos = 0;
}
fdsDoEnv();
fdsDoEnv();
fdsDoEnv();
}
}

if(fds_apu.modEnabled)
//mostly follows logic of http://forums.nesdev.com/viewtopic.php?p=232662#p232662
FIXNES_NOINLINE void fdsAudioMasterUpdate()
{
if(!fds_apu.masterEnable) //when master is off, keep timer locked
fds_apu.tickCnt = 0;
else if((fds_apu.tickCnt&0xF) == 0) //do updates on counter wrap
{
fds_apu.curModClock += fds_apu.modFreq;
if(fds_apu.curModClock&(~0xFFFF))
//see if mod is enabled
if(fds_apu.modEnabled)
{
fds_apu.curModClock &= 0xFFFF;
//do mod stuff
switch((fds_apu.modulation[fds_apu.curModPos]&7))
{
case 1:
fds_apu.modCounter++;
break;
case 2:
fds_apu.modCounter += 2;
break;
case 3:
fds_apu.modCounter += 4;
break;
case 4:
fds_apu.modCounter = 0;
break;
case 5:
fds_apu.modCounter -= 4;
break;
case 6:
fds_apu.modCounter -= 2;
break;
case 7:
fds_apu.modCounter -= 1;
break;
default:
break;
}
if(fds_apu.modCounter & 0x40) //7-bit signed
fds_apu.modCounter |= 0x80;
else
fds_apu.modCounter &= ~0x80;
//move along mod pos
fds_apu.curModPos++; fds_apu.curModPos &= 0x3F;
// from https://forums.nesdev.com/viewtopic.php?f=3&t=10233
// 1. multiply counter by gain, lose lowest 4 bits of result but "round" in a strange way
int16_t temp = fds_apu.modCounter * fds_apu.sweepModGain;
uint8_t remainder = temp & 0xF;
temp >>= 4;
if((remainder > 0) && ((temp & 0x80) == 0))
fds_apu.curModClock += fds_apu.modFreq;
//see if real overflow or force bit was set
if(fds_apu.curModClock&(~0xFFF) || fds_apu.modForce)
{
if (fds_apu.modCounter < 0)
temp -= 1;
fds_apu.curModClock &= 0xFFF;
//do mod stuff
switch((fds_apu.modulation[fds_apu.curModPos>>1]))
{
case 1:
fds_apu.modCounter++;
break;
case 2:
fds_apu.modCounter += 2;
break;
case 3:
fds_apu.modCounter += 4;
break;
case 4:
fds_apu.modCounter = 0;
break;
case 5:
fds_apu.modCounter -= 4;
break;
case 6:
fds_apu.modCounter -= 2;
break;
case 7:
fds_apu.modCounter -= 1;
break;
default:
break;
}
if(fds_apu.modCounter & 0x40) //7-bit signed
fds_apu.modCounter |= 0x80;
else
temp += 2;
fds_apu.modCounter &= ~0x80;
//move along mod pos AFTER handling the overflow
fds_apu.curModPos++; fds_apu.curModPos &= 0x3F;
}
// 2. wrap if a certain range is exceeded
if(temp >= 192)
temp -= 256;
else if(temp < -64)
temp += 256;
// 3. multiply result by pitch, then round to nearest while dropping 6 bits
temp = fds_apu.freq * temp;
remainder = temp & 0x3F;
temp >>= 6;
if(remainder >= 32)
temp += 1;
// final mod result is in temp
fds_apu.modChange = temp;
}
//update master always
int16_t temp = fds_apu.modCounter * fds_apu.sweepModGain;
if((temp & 0x0f) && !(temp & 0x800))
temp += 0x20;
temp += 0x400;
uint8_t multi = (temp >> 4);
//add change to accumulator and update wave
fds_apu.curMasterClock += fds_apu.freq * multi;
fds_apu.curMasterClock &= 0xFFFFFF; //24-bit overall
fds_apu.curWave = fds_apu.wave[fds_apu.curMasterClock>>18];
}
fds_apu.tickCnt++;
}

void fdsAudioSet8(uint16_t addr, uint8_t val)
Expand All @@ -245,14 +239,11 @@ void fdsAudioSet8(uint16_t addr, uint8_t val)
case 3:
fds_apu.masterEnable = ((val&0x80) == 0);
fds_apu.freq = (fds_apu.freq&0xFF) | ((val&0xF)<<8);
if(fds_apu.freq == 0)
fds_apu.masterEnable = false;
if(!fds_apu.masterEnable)
{
//disabling resets clock and wave pos
fds_apu.curMasterClock = 0;
fds_apu.curWavePos = 0;
fds_apu.curWave = fds_apu.wave[fds_apu.curWavePos];
fds_apu.curWave = fds_apu.wave[0];
}
fds_apu.envMasterEnable = ((val&0x40) == 0);
if(!fds_apu.envMasterEnable)
Expand Down Expand Up @@ -283,24 +274,21 @@ void fdsAudioSet8(uint16_t addr, uint8_t val)
break;
case 7:
fds_apu.modEnabled = ((val&0x80) == 0);
fds_apu.modForce = ((val&0x40) != 0);
fds_apu.modFreq = (fds_apu.modFreq&0xFF) | ((val&0xF)<<8);
if(fds_apu.modFreq == 0)
fds_apu.modEnabled = false;
if(!fds_apu.modEnabled)
{
//disabling resets clock
fds_apu.curModClock = 0;
//make sure to clear old change too
fds_apu.modChange = 0;
//clears lower bit of this too
fds_apu.curModPos &= ~1;
}
break;
case 8:
if(!fds_apu.modEnabled)
{
fds_apu.modulation[fds_apu.curModPos] = val;
fds_apu.curModPos++; fds_apu.curModPos&=0x3F;
fds_apu.modulation[fds_apu.curModPos] = val;
fds_apu.curModPos++; fds_apu.curModPos&=0x3F;
fds_apu.modulation[fds_apu.curModPos>>1] = val&7;
fds_apu.curModPos += 2; fds_apu.curModPos &= 0x3F;
}
break;
case 9:
Expand Down
2 changes: 1 addition & 1 deletion main.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -38,7 +38,7 @@
#define DEBUG_KEY 0
#define DEBUG_LOAD_INFO 1

const char *VERSION_STRING = "fixNES Alpha v1.3.0";
const char *VERSION_STRING = "fixNES Alpha v1.3.1";
static char window_title[256];
static char window_title_pause[256];

Expand Down

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