apu

type APU struct {
	Enabled    bool    `msgpack:"-"`
	SampleRate float64 `msgpack:"-"`

	Square   [2]Square
	Triangle Triangle
	Noise    Noise
	DMC      DMC

	Cycle       uint
	FramePeriod uint8
	FrameValue  byte

	IRQEnabled bool `msgpack:"alias:IrqEnabled"`
	IRQPending bool `msgpack:"alias:IrqPending"`
	// contains filtered or unexported fields
}

type CPU interface {
	memory.Read8
	interrupt.Stall
}

type DMC struct {
	Enabled bool
	Value   byte

	IRQEnabled bool `msgpack:"alias:IrqEnabled"`
	IRQPending bool `msgpack:"alias:IrqPending"`
	Loop       bool

	TickPeriod byte
	TickValue  byte

	SampleAddr uint16
	SampleLen  uint16

	CurrAddr      uint16
	CurrLen       uint16
	ShiftRegister byte
	BitCount      byte
	// contains filtered or unexported fields
}

type Noise struct {
	Enabled bool

	EnvelopeEnabled bool
	EnvelopeLoop    bool
	EnvelopeStart   bool
	EnvelopeVol     byte
	EnvelopePeriod  byte
	EnvelopeValue   byte

	Volume byte

	LoopNoise     bool
	ShiftRegister uint16

	TimerPeriod uint16
	TimerValue  uint16

	LengthEnabled bool
	LengthValue   byte
}

type Square struct {
	Enabled  bool
	Channel1 bool

	DutyMode  byte
	DutyValue byte

	EnvelopeEnabled bool
	EnvelopePeriod  byte
	EnvelopeLoop    bool
	EnvelopeStart   bool
	EnvelopeVol     byte
	EnvelopeValue   byte

	Volume byte

	SweepEnabled bool
	SweepPeriod  byte
	SweepNegate  bool
	SweepShift   byte
	SweepReload  bool
	SweepValue   byte

	LengthEnabled bool
	LengthValue   byte

	TimerPeriod uint16
	TimerValue  uint16
}

type Triangle struct {
	Enabled bool

	LengthEnabled bool
	LengthValue   byte

	CounterPeriod byte
	CounterValue  byte
	CounterReload bool

	DutyValue byte

	TimerPeriod uint16
	TimerValue  uint16
}