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@ichirin2501
ichirin2501 committed Jan 8, 2024
1 parent e8c2779 commit 6c932d9
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Showing 13 changed files with 449 additions and 481 deletions.
52 changes: 26 additions & 26 deletions nes/apu.go
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Original file line number Diff line number Diff line change
Expand Up @@ -29,7 +29,7 @@ type Player interface {
Sample(float32)
}

type Option func(*APU)
type APUOption func(*APU)

type APU struct {
cpu *Interrupter
Expand All @@ -53,7 +53,7 @@ type APU struct {
writeDelayFrameCounter byte
}

func NewAPU(cpu *Interrupter, p Player, opts ...Option) *APU {
func NewAPU(cpu *Interrupter, p Player, opts ...APUOption) *APU {
apu := &APU{
player: p,
cpu: cpu,
Expand All @@ -76,21 +76,21 @@ func NewAPU(cpu *Interrupter, p Player, opts ...Option) *APU {
return apu
}

func WithSampleRate(sampleRate int) Option {
func WithSampleRate(sampleRate int) APUOption {
return func(apu *APU) {
apu.sampleRate = sampleRate
}
}

func (apu *APU) PowerUp() {
// todo
apu.WriteStatus(0)
apu.writeStatus(0)
apu.noise.shiftRegister = 1
}

func (apu *APU) Reset() {
// todo
apu.WriteStatus(0)
apu.writeStatus(0)
}

func (apu *APU) Step() {
Expand Down Expand Up @@ -147,71 +147,71 @@ func writePulseLengthAndTimerHigh(p *pulse, val byte) {
}

// $4000
func (apu *APU) WritePulse1Controller(val byte) {
func (apu *APU) writePulse1Controller(val byte) {
writePulseController(apu.pulse1, val)
}

// $4001
func (apu *APU) WritePulse1Sweep(val byte) {
func (apu *APU) writePulse1Sweep(val byte) {
writePulseSweep(apu.pulse1, val)
}

// $4002
func (apu *APU) WritePulse1TimerLow(val byte) {
func (apu *APU) writePulse1TimerLow(val byte) {
writePulseTimerLow(apu.pulse1, val)
}

// $4003
func (apu *APU) WritePulse1LengthAndTimerHigh(val byte) {
func (apu *APU) writePulse1LengthAndTimerHigh(val byte) {
writePulseLengthAndTimerHigh(apu.pulse1, val)
}

// $4004
func (apu *APU) WritePulse2Controller(val byte) {
func (apu *APU) writePulse2Controller(val byte) {
writePulseController(apu.pulse2, val)
}

// $4005
func (apu *APU) WritePulse2Sweep(val byte) {
func (apu *APU) writePulse2Sweep(val byte) {
writePulseSweep(apu.pulse2, val)
}

// $4006
func (apu *APU) WritePulse2TimerLow(val byte) {
func (apu *APU) writePulse2TimerLow(val byte) {
writePulseTimerLow(apu.pulse2, val)
}

// $4007
func (apu *APU) WritePulse2LengthAndTimerHigh(val byte) {
func (apu *APU) writePulse2LengthAndTimerHigh(val byte) {
writePulseLengthAndTimerHigh(apu.pulse2, val)
}

// $4008
// CRRR RRRR Length counter halt / linear counter control (C), linear counter load (R)
func (apu *APU) WriteTriangleController(val byte) {
func (apu *APU) writeTriangleController(val byte) {
apu.tnd.lc.halt = (val & 0x80) == 0x80
apu.tnd.linearCounterCtrl = (val & 0x80) == 0x80
apu.tnd.linearCounterPeriod = val & 0x7F
}

// $400A
// TTTT TTTT Timer low (T)
func (apu *APU) WriteTriangleTimerLow(val byte) {
func (apu *APU) writeTriangleTimerLow(val byte) {
// 11bit
apu.tnd.timer.period = (apu.tnd.timer.period & 0x0700) | uint16(val)
}

// $400B
// LLLL LTTT Length counter load (L), timer high (T)
func (apu *APU) WriteTriangleLengthAndTimerHigh(val byte) {
func (apu *APU) writeTriangleLengthAndTimerHigh(val byte) {
apu.tnd.lc.load(val >> 3)
apu.tnd.timer.period = (apu.tnd.timer.period & 0x00FF) | (uint16(val&0b111) << 8)
apu.tnd.linearCounterReload = true
}

// $400C
// --LC VVVV el loop / length counter halt (L), constant volume (C), volume/envelope (V)
func (apu *APU) WriteNoiseController(val byte) {
func (apu *APU) writeNoiseController(val byte) {
apu.noise.lc.halt = (val & 0x20) == 0x20
apu.noise.el.loop = (val & 0x20) == 0x20
apu.noise.el.constantVolume = (val & 0x10) == 0x10
Expand All @@ -220,47 +220,47 @@ func (apu *APU) WriteNoiseController(val byte) {

// $400E
// M---.PPPP Mode and period (write)
func (apu *APU) WriteNoiseLoopAndPeriod(val byte) {
func (apu *APU) writeNoiseLoopAndPeriod(val byte) {
apu.noise.mode = (val & 0x80) == 0x80
apu.noise.loadPeriod(val & 0x0F)
}

// $400F
// LLLL L--- Length counter load (L)
func (apu *APU) WriteNoiseLength(val byte) {
func (apu *APU) writeNoiseLength(val byte) {
apu.noise.lc.load(val >> 3)
apu.noise.el.start = true
}

// $4010
// IL-- RRRR IRQ enable (I), loop (L), frequency (R)
func (apu *APU) WriteDMCController(val byte) {
func (apu *APU) writeDMCController(val byte) {
apu.dmc.irqEnabled = (val & 0x80) == 0x80
apu.dmc.loop = (val & 0x40) == 0x40
apu.dmc.freq = val & 0x0F
}

// $4011
// -DDD DDDD load counter (D)
func (apu *APU) WriteDMCLoadCounter(val byte) {
func (apu *APU) writeDMCLoadCounter(val byte) {
apu.dmc.counter = val & 0x7F
}

// $4012
// AAAA AAAA Sample address (A)
func (apu *APU) WriteDMCSampleAddr(val byte) {
func (apu *APU) writeDMCSampleAddr(val byte) {
apu.dmc.sampleAddr = val
}

// $4013
// LLLL LLLL Sample length (L)
func (apu *APU) WriteDMCSampleLength(val byte) {
func (apu *APU) writeDMCSampleLength(val byte) {
apu.dmc.sampleLength = val
}

// $4015 read
// IF-D NT21 DMC interrupt (I), frame interrupt (F), DMC active (D), length counter > 0 (N/T/2/1)
func (apu *APU) ReadStatus() byte {
func (apu *APU) readStatus() byte {
res := byte(0)
if apu.pulse1.lc.value > 0 {
res |= 0x01
Expand Down Expand Up @@ -309,7 +309,7 @@ func (apu *APU) PeekStatus() byte {

// $4015 write
// ---D NT21 Enable DMC (D), noise (N), triangle (T), and pulse channels (2/1)
func (apu *APU) WriteStatus(val byte) {
func (apu *APU) writeStatus(val byte) {
apu.dmc.setEnabled((val & 0x10) == 0x10)
apu.noise.lc.setEnabled((val & 0x08) == 0x08)
apu.tnd.lc.setEnabled((val & 0x04) == 0x04)
Expand All @@ -318,7 +318,7 @@ func (apu *APU) WriteStatus(val byte) {
}

// $4017
func (apu *APU) WriteFrameCounter(val byte) {
func (apu *APU) writeFrameCounter(val byte) {
// https://www.nesdev.org/wiki/APU#Frame_Counter_($4017)
// > Writing to $4017 resets the frame counter and the quarter/half frame triggers happen simultaneously,
// > but only on "odd" cycles (and only after the first "even" cycle after the write occurs)
Expand Down
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