gb/src/apu/types.rs

599 lines
13 KiB
Rust

use bitfield::bitfield;
pub(crate) mod ch1 {
use super::bitfield;
bitfield! {
pub struct Sweep(u8);
impl Debug;
_period, _: 6, 4;
from into SweepDirection, _direction, _: 3, 3;
_shift_count, _: 2, 0;
}
impl Sweep {
pub(crate) fn period(&self) -> u8 {
self._period()
}
pub(crate) fn shift_count(&self) -> u8 {
self._shift_count()
}
pub(crate) fn direction(&self) -> SweepDirection {
self._direction()
}
}
impl Copy for Sweep {}
impl Clone for Sweep {
fn clone(&self) -> Self {
*self
}
}
impl Default for Sweep {
fn default() -> Self {
Self(0)
}
}
impl From<u8> for Sweep {
fn from(byte: u8) -> Self {
Self(byte)
}
}
impl From<Sweep> for u8 {
fn from(sweep: Sweep) -> Self {
sweep.0
}
}
#[derive(Debug, Clone, Copy)]
pub(crate) enum SweepDirection {
Increase = 0,
Decrease = 1,
}
impl From<u8> for SweepDirection {
fn from(byte: u8) -> Self {
match byte & 0x01 {
0b00 => Self::Increase,
0b01 => Self::Decrease,
_ => unreachable!("{:04X} is not a valid value for SweepChange", byte),
}
}
}
impl From<SweepDirection> for u8 {
fn from(change: SweepDirection) -> Self {
change as u8
}
}
}
pub(super) mod ch3 {
#[derive(Debug, Clone, Copy)]
pub(crate) enum Volume {
Mute = 0,
Full = 1,
Half = 2,
Quarter = 3,
}
impl Volume {
pub(crate) fn shift_count(&self) -> u8 {
use Volume::*;
match *self {
Mute => 4,
Full => 0,
Half => 1,
Quarter => 2,
}
}
}
impl Default for Volume {
fn default() -> Self {
Self::Mute
}
}
}
pub(super) mod ch4 {
use super::bitfield;
bitfield! {
pub struct PolynomialCounter(u8);
impl Debug;
_shift_count, _: 7, 4;
from into CounterWidth, _counter_width, _: 3, 3;
_divisor_code, _: 2, 0;
}
impl PolynomialCounter {
pub(crate) fn divisor_code(&self) -> u8 {
self._divisor_code()
}
pub(crate) fn counter_width(&self) -> CounterWidth {
self._counter_width()
}
pub(crate) fn shift_count(&self) -> u8 {
self._shift_count()
}
}
impl Copy for PolynomialCounter {}
impl Clone for PolynomialCounter {
fn clone(&self) -> Self {
*self
}
}
impl Default for PolynomialCounter {
fn default() -> Self {
Self(0)
}
}
impl From<u8> for PolynomialCounter {
fn from(byte: u8) -> Self {
Self(byte)
}
}
impl From<PolynomialCounter> for u8 {
fn from(poly: PolynomialCounter) -> Self {
poly.0
}
}
#[derive(Debug, Clone, Copy)]
pub(crate) enum CounterWidth {
Long, // 15 bits long
Short, // 7 bits long
}
impl From<u8> for CounterWidth {
fn from(byte: u8) -> Self {
match byte & 0x01 {
0b00 => Self::Short,
0b01 => Self::Long,
_ => unreachable!("{:#04X} is not a valid value for CounterWidth"),
}
}
}
impl From<CounterWidth> for u8 {
fn from(counter_width: CounterWidth) -> Self {
counter_width as u8
}
}
bitfield! {
pub struct Frequency(u8);
impl Debug;
_initial, _: 7;
_length_enable, _: 6;
}
impl Frequency {
pub(crate) fn length_enable(&self) -> bool {
self._length_enable()
}
pub(crate) fn initial(&self) -> bool {
self._initial()
}
}
impl Copy for Frequency {}
impl Clone for Frequency {
fn clone(&self) -> Self {
*self
}
}
impl Default for Frequency {
fn default() -> Self {
Self(0)
}
}
impl From<u8> for Frequency {
fn from(byte: u8) -> Self {
Self(byte & 0xC0) // Only bits 7 and 6 hold anything of value
}
}
impl From<Frequency> for u8 {
fn from(state: Frequency) -> Self {
state.0 & 0x40 // Only bit 6 holds anything of value
}
}
}
pub(super) mod common {
use super::bitfield;
bitfield! {
pub struct FrequencyHigh(u8);
impl Debug;
_trigger, _: 7;
_length_enable, _: 6;
pub freq_bits, set_freq_bits: 2, 0;
}
impl FrequencyHigh {
pub(crate) fn trigger(&self) -> bool {
self._trigger()
}
pub(crate) fn length_enable(&self) -> bool {
self._length_enable()
}
}
impl Copy for FrequencyHigh {}
impl Clone for FrequencyHigh {
fn clone(&self) -> Self {
*self
}
}
impl Default for FrequencyHigh {
fn default() -> Self {
Self(0)
}
}
impl From<u8> for FrequencyHigh {
fn from(byte: u8) -> Self {
Self(byte)
}
}
impl From<FrequencyHigh> for u8 {
fn from(freq: FrequencyHigh) -> Self {
freq.0 & 0x40 // Only bit 6 can be read
}
}
bitfield! {
pub struct VolumeEnvelope(u8);
impl Debug;
_init_vol, _: 7, 4;
from into EnvelopeDirection, _direction, _: 3, 3;
_period, _: 2, 0;
}
impl VolumeEnvelope {
pub(crate) fn init_vol(&self) -> u8 {
self._init_vol()
}
pub(crate) fn direction(&self) -> EnvelopeDirection {
self._direction()
}
pub(crate) fn period(&self) -> u8 {
self._period()
}
}
impl Copy for VolumeEnvelope {}
impl Clone for VolumeEnvelope {
fn clone(&self) -> Self {
*self
}
}
impl Default for VolumeEnvelope {
fn default() -> Self {
Self(0)
}
}
impl From<u8> for VolumeEnvelope {
fn from(byte: u8) -> Self {
Self(byte)
}
}
impl From<VolumeEnvelope> for u8 {
fn from(envelope: VolumeEnvelope) -> Self {
envelope.0
}
}
#[derive(Debug, Clone, Copy)]
pub(crate) enum EnvelopeDirection {
Decrease = 0,
Increase = 1,
}
impl From<u8> for EnvelopeDirection {
fn from(byte: u8) -> Self {
match byte & 0b01 {
0b00 => Self::Decrease,
0b01 => Self::Increase,
_ => unreachable!("{:#04X} is not a valid value for EnvelopeDirection", byte),
}
}
}
impl From<EnvelopeDirection> for u8 {
fn from(direction: EnvelopeDirection) -> Self {
direction as u8
}
}
impl Default for EnvelopeDirection {
fn default() -> Self {
Self::Decrease
}
}
bitfield! {
pub struct SoundDuty(u8);
impl Debug;
from into WavePattern, _wave_pattern, _: 7, 6;
_sound_length, _: 5, 0;
}
impl SoundDuty {
pub(crate) fn wave_pattern(&self) -> WavePattern {
self._wave_pattern()
}
pub(crate) fn sound_length(&self) -> u8 {
self._sound_length()
}
}
impl Copy for SoundDuty {}
impl Clone for SoundDuty {
fn clone(&self) -> Self {
*self
}
}
impl Default for SoundDuty {
fn default() -> Self {
Self(0)
}
}
impl From<u8> for SoundDuty {
fn from(byte: u8) -> Self {
Self(byte)
}
}
impl From<SoundDuty> for u8 {
fn from(duty: SoundDuty) -> Self {
duty.0 & 0xC0 // Only bits 7 and 6 can be read
}
}
#[derive(Debug, Clone, Copy)]
pub(crate) enum WavePattern {
OneEighth = 0, // 12.5% ( _-------_-------_------- )
OneQuarter = 1, // 25% ( __------__------__------ )
OneHalf = 2, // 50% ( ____----____----____---- ) (normal)
ThreeQuarters = 3, // 75% ( ______--______--______-- )
}
impl WavePattern {
pub(crate) const fn amplitude(&self, index: u8) -> u8 {
use WavePattern::*;
let i = 7 - index; // an index of 0 should get the highest bit
match *self {
OneEighth => (0b00000001 >> i) & 0x01,
OneQuarter => (0b10000001 >> i) & 0x01,
OneHalf => (0b10000111 >> i) & 0x01,
ThreeQuarters => (0b01111110 >> i) & 0x01,
}
}
}
impl Default for WavePattern {
fn default() -> Self {
Self::OneEighth // Rationale: OneEighth is 0x00
}
}
impl From<WavePattern> for u8 {
fn from(pattern: WavePattern) -> Self {
pattern as Self
}
}
impl From<u8> for WavePattern {
fn from(byte: u8) -> Self {
match byte & 0b11 {
0b00 => Self::OneEighth,
0b01 => Self::OneQuarter,
0b10 => Self::OneHalf,
0b11 => Self::ThreeQuarters,
_ => unreachable!("{:#04X} is not a valid value for WavePattern", byte),
}
}
}
}
bitfield! {
pub struct SoundOutput(u8);
impl Debug;
pub ch4_left, _: 7;
pub ch3_left, _: 6;
pub ch2_left, _: 5;
pub ch1_left, _: 4;
pub ch4_right, _: 3;
pub ch3_right, _: 2;
pub ch2_right, _: 1;
pub ch1_right, _: 0;
}
impl SoundOutput {
pub(super) fn ch1(&self) -> (bool, bool) {
(self.ch1_left(), self.ch1_right())
}
pub(super) fn ch2(&self) -> (bool, bool) {
(self.ch2_left(), self.ch2_right())
}
pub(super) fn ch3(&self) -> (bool, bool) {
(self.ch3_left(), self.ch3_right())
}
pub(super) fn ch4(&self) -> (bool, bool) {
(self.ch4_left(), self.ch4_right())
}
}
impl Copy for SoundOutput {}
impl Clone for SoundOutput {
fn clone(&self) -> Self {
*self
}
}
impl Default for SoundOutput {
fn default() -> Self {
Self(0)
}
}
impl From<u8> for SoundOutput {
fn from(byte: u8) -> Self {
Self(byte)
}
}
impl From<SoundOutput> for u8 {
fn from(output: SoundOutput) -> Self {
output.0
}
}
bitfield! {
pub struct ChannelControl(u8);
impl Debug;
vin_left, _: 7;
_left_volume, _: 6, 4;
vin_right, _: 3;
_right_volume, _: 2, 0;
}
impl ChannelControl {
pub(crate) fn left_volume(&self) -> f32 {
self._left_volume() as f32
}
pub(crate) fn right_volume(&self) -> f32 {
self._right_volume() as f32
}
}
impl Copy for ChannelControl {}
impl Clone for ChannelControl {
fn clone(&self) -> Self {
*self
}
}
impl Default for ChannelControl {
fn default() -> Self {
Self(0)
}
}
impl From<u8> for ChannelControl {
fn from(byte: u8) -> Self {
Self(byte)
}
}
impl From<ChannelControl> for u8 {
fn from(ctrl: ChannelControl) -> Self {
ctrl.0
}
}
pub(super) mod fs {
#[derive(Debug)]
pub(crate) struct FrameSequencer {
step: u8,
state: State,
}
impl Default for FrameSequencer {
fn default() -> Self {
Self {
step: Default::default(),
state: State::Length,
}
}
}
impl FrameSequencer {
pub(crate) fn next(&mut self) {
use State::*;
self.step = (self.step + 1) % 8;
self.state = match self.step {
1 | 3 | 5 => Nothing,
0 | 4 => Length,
2 | 6 => LengthAndSweep,
7 => Envelope,
_ => unreachable!("Step {} is invalid for the Frame Sequencer", self.step),
};
}
fn peek(&self) -> State {
use State::*;
match (self.step + 1) % 8 {
1 | 3 | 5 => Nothing,
0 | 4 => Length,
2 | 6 => LengthAndSweep,
7 => Envelope,
num => unreachable!("Step {} is invalid for the Frame Sequencer", num),
}
}
pub(crate) fn next_clocks_length(&self) -> bool {
use State::*;
match self.peek() {
Length | LengthAndSweep => true,
Nothing | Envelope => false,
}
}
pub(crate) fn state(&self) -> State {
self.state
}
pub(crate) fn reset(&mut self) {
self.step = Default::default();
self.state = State::Length;
}
}
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub(crate) enum State {
Length,
Nothing,
LengthAndSweep,
Envelope,
}
}