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chore(apu): implement more obscure behaviour 

implement capacitor
This commit is contained in:
Rekai Nyangadzayi Musuka 2021-10-30 18:41:31 +09:00
parent 548945a4ee
commit 2ef8fefbb7
2 changed files with 91 additions and 31 deletions
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87
src/apu.rs
View File

@ -1,3 +1,4 @@
use crate::apu::gen::SAMPLE_RATE;
use crate::bus::BusIo;
use crate::emu::SM83_CLOCK_SPEED;
use gen::SampleProducer;
@ -5,7 +6,7 @@ use types::ch1::{Sweep, SweepDirection};
use types::ch3::Volume as Ch3Volume;
use types::ch4::{CounterWidth, Frequency as Ch4Frequency, PolynomialCounter};
use types::common::{EnvelopeDirection, FrequencyHigh, SoundDuty, VolumeEnvelope};
use types::fs::{FrameSequencer, State as FrameSequencerState};
use types::fs::{FrameSequencer, State as FSState};
use types::{ChannelControl, SoundOutput};
pub mod gen;
@ -31,6 +32,8 @@ pub struct Apu {
prod: Option<SampleProducer<f32>>,
sample_counter: u64,
cap: f32,
}
impl BusIo for Apu {
@ -66,7 +69,7 @@ impl BusIo for Apu {
0x11 if self.ctrl.enabled => self.ch1.set_duty(byte),
0x12 if self.ctrl.enabled => self.ch1.set_envelope(byte),
0x13 if self.ctrl.enabled => self.ch1.set_freq_lo(byte),
0x14 if self.ctrl.enabled => self.ch1.set_freq_hi(byte),
0x14 if self.ctrl.enabled => self.ch1.set_freq_hi(&self.sequencer, byte),
0x16 if self.ctrl.enabled => self.ch2.set_duty(byte),
0x17 if self.ctrl.enabled => self.ch2.set_envelope(byte),
0x18 if self.ctrl.enabled => self.ch2.set_freq_lo(byte),
@ -96,7 +99,7 @@ impl Apu {
// Frame Sequencer (512Hz)
if self.is_falling_edge(12, div) {
use FrameSequencerState::*;
use FSState::*;
match self.sequencer.state() {
Length => self.clock_length(),
@ -121,25 +124,33 @@ impl Apu {
if self.sample_counter >= SM83_CLOCK_SPEED {
self.sample_counter %= SM83_CLOCK_SPEED;
if let Some(ref mut prod) = self.prod {
if let Some(prod) = self.prod.as_mut() {
if prod.available_blocking() {
// Sample the APU
let ch1_amplitude =
Self::high_pass(&mut self.cap, self.ch1.amplitude(), self.ch1.enabled);
let (left, right) = self.ctrl.out.ch1();
let ch1_left = if left { self.ch1.amplitude() } else { 0.0 };
let ch1_right = if right { self.ch1.amplitude() } else { 0.0 };
let ch1_left = if left { ch1_amplitude } else { 0.0 };
let ch1_right = if right { ch1_amplitude } else { 0.0 };
let ch2_amplitude =
Self::high_pass(&mut self.cap, self.ch2.amplitude(), self.ch2.enabled);
let (left, right) = self.ctrl.out.ch2();
let ch2_left = if left { self.ch2.amplitude() } else { 0.0 };
let ch2_right = if right { self.ch2.amplitude() } else { 0.0 };
let ch2_left = if left { ch2_amplitude } else { 0.0 };
let ch2_right = if right { ch2_amplitude } else { 0.0 };
let ch3_amplitude =
Self::high_pass(&mut self.cap, self.ch3.amplitude(), self.ch3.enabled);
let (left, right) = self.ctrl.out.ch3();
let ch3_left = if left { self.ch3.amplitude() } else { 0.0 };
let ch3_right = if right { self.ch3.amplitude() } else { 0.0 };
let ch3_left = if left { ch3_amplitude } else { 0.0 };
let ch3_right = if right { ch3_amplitude } else { 0.0 };
let ch4_amplitude =
Self::high_pass(&mut self.cap, self.ch4.amplitude(), self.ch4.enabled);
let (left, right) = self.ctrl.out.ch4();
let ch4_left = if left { self.ch4.amplitude() } else { 0.0 };
let ch4_right = if right { self.ch4.amplitude() } else { 0.0 };
let ch4_left = if left { ch4_amplitude } else { 0.0 };
let ch4_right = if right { ch4_amplitude } else { 0.0 };
let left_mixed = (ch1_left + ch2_left + ch3_left + ch4_left) / 4.0;
let right_mixed = (ch1_right + ch2_right + ch3_right + ch4_right) / 4.0;
@ -214,20 +225,20 @@ impl Apu {
self.ch4.enabled = Default::default();
}
fn process_length(freq_hi: &FrequencyHigh, length_timer: &mut u16, enabled: &mut bool) {
if freq_hi.length_disable() && *length_timer > 0 {
*length_timer -= 1;
fn process_length(freq_hi: &FrequencyHigh, counter: &mut u16, enabled: &mut bool) {
if freq_hi.length_enable() && *counter > 0 {
*counter -= 1;
// Check in this scope ensures (only) the above subtraction
// made length_timer 0
if *length_timer == 0 {
if *counter == 0 {
*enabled = false;
}
}
}
fn ch4_process_length(freq: &Ch4Frequency, length_timer: &mut u16, enabled: &mut bool) {
if freq.length_disable() && *length_timer > 0 {
if freq.length_enable() && *length_timer > 0 {
*length_timer -= 1;
// Check in this scope ensures (only) the above subtraction
@ -241,7 +252,7 @@ impl Apu {
fn clock_length(&mut self) {
Self::process_length(
&self.ch1.freq_hi,
&mut self.ch1.length_timer,
&mut self.ch1.length_counter,
&mut self.ch1.enabled,
);
@ -334,6 +345,19 @@ impl Apu {
None => false,
}
}
fn high_pass(capacitor: &mut f32, input: f32, enabled: bool) -> f32 {
const CHARGE_FACTOR: f32 = 0.999958;
let mut output = 0.0;
if enabled {
output = input - *capacitor;
*capacitor =
input - output * CHARGE_FACTOR.powi(SM83_CLOCK_SPEED as i32 / SAMPLE_RATE as i32);
}
output
}
}
#[derive(Debug, Default)]
@ -405,7 +429,7 @@ pub(crate) struct Channel1 {
sweep_enabled: bool,
// Length Functionality
length_timer: u16,
length_counter: u16,
freq_timer: u16,
duty_pos: u8,
@ -432,7 +456,7 @@ impl Channel1 {
/// 0xFF11 | NR11 - Channel 1 Sound length / Wave pattern duty
pub(crate) fn set_duty(&mut self, byte: u8) {
self.duty = byte.into();
self.length_timer = 64 - self.duty.sound_length() as u16;
self.length_counter = 64 - self.duty.sound_length() as u16;
}
/// 0xFF12 | NR12 - Channel 1 Volume Envelope
@ -460,9 +484,20 @@ impl Channel1 {
}
/// 0xFF14 | NR14 - Channel 1 Frequency high
pub(crate) fn set_freq_hi(&mut self, byte: u8) {
pub(crate) fn set_freq_hi(&mut self, fs: &FrameSequencer, byte: u8) {
let prev_le = self.freq_hi.length_enable();
self.freq_hi = byte.into();
if !fs.next_clocks_length() {
if !prev_le && self.freq_hi.length_enable() && self.length_counter != 0 {
self.length_counter -= 1;
if self.length_counter == 0 && !self.freq_hi.initial() {
self.enabled = false;
}
}
}
// If this bit is set, a trigger event occurs
if self.freq_hi.initial() {
if self.is_dac_enabled() {
@ -470,9 +505,13 @@ impl Channel1 {
}
// Length behaviour during trigger event
if self.length_timer == 0 {
self.length_timer = 64;
}
if self.length_counter == 0 {
self.length_counter = if self.freq_hi.length_enable() && !fs.next_clocks_length() {
63
} else {
64
};
};
// Envelope Behaviour during trigger event
self.period_timer = self.envelope.period();

35
src/apu/types.rs
View File

@ -178,12 +178,12 @@ pub(super) mod ch4 {
pub struct Frequency(u8);
impl Debug;
_initial, _: 7;
_length_disable, _: 6;
_length_enable, _: 6;
}
impl Frequency {
pub(crate) fn length_disable(&self) -> bool {
self._length_disable()
pub(crate) fn length_enable(&self) -> bool {
self._length_enable()
}
pub(crate) fn initial(&self) -> bool {
@ -224,7 +224,7 @@ pub(super) mod common {
pub struct FrequencyHigh(u8);
impl Debug;
_initial, _: 7;
_length_disable, _: 6;
_length_enable, _: 6;
pub freq_bits, set_freq_bits: 2, 0;
}
@ -233,8 +233,8 @@ pub(super) mod common {
self._initial()
}
pub(crate) fn length_disable(&self) -> bool {
self._length_disable()
pub(crate) fn length_enable(&self) -> bool {
self._length_enable()
}
}
@ -557,6 +557,27 @@ pub(super) mod fs {
};
}
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
}
@ -567,7 +588,7 @@ pub(super) mod fs {
}
}
#[derive(Debug, Clone, Copy)]
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub(crate) enum State {
Length,
Nothing,