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fix(apu): better emulate behaviour of apu channel DACs

This commit is contained in:
Rekai Nyangadzayi Musuka 2021-08-17 21:26:22 -05:00
parent 9b2c91445a
commit 8fea8eb1ff
1 changed files with 24 additions and 13 deletions
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37
src/apu.rs
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@ -412,9 +412,12 @@ pub(crate) struct Channel1 {
impl Channel1 {
fn amplitude(&self) -> f32 {
let dac_input = self.duty.wave_pattern().amplitude(self.duty_pos) * self.current_volume;
(dac_input as f32 / 7.5) - 1.0
if self.is_dac_enabled() && self.enabled {
let input = self.duty.wave_pattern().amplitude(self.duty_pos) * self.current_volume;
(input as f32 / 7.5) - 1.0
} else {
0.0
}
}
fn clock(&mut self) {
@ -565,9 +568,12 @@ pub(crate) struct Channel2 {
impl Channel2 {
fn amplitude(&self) -> f32 {
let dac_input = self.duty.wave_pattern().amplitude(self.duty_pos) * self.current_volume;
(dac_input as f32 / 7.5) - 1.0
if self.is_dac_enabled() && self.enabled {
let input = self.duty.wave_pattern().amplitude(self.duty_pos) * self.current_volume;
(input as f32 / 7.5) - 1.0
} else {
0.0
}
}
fn clock(&mut self) {
@ -745,10 +751,12 @@ impl Channel3 {
}
fn amplitude(&self) -> f32 {
let dac_input =
(self.read_sample(self.offset) >> self.volume.shift_count()) * self.enabled as u8;
(dac_input as f32 / 7.5) - 1.0
if self.enabled {
let input = self.read_sample(self.offset) >> self.volume.shift_count();
(input as f32 / 7.5) - 1.0
} else {
0.0
}
}
fn clock(&mut self) {
@ -863,9 +871,12 @@ impl Channel4 {
}
fn amplitude(&self) -> f32 {
let dac_input = (!self.lf_shift & 0x01) as u8 * self.current_volume;
(dac_input as f32 / 7.5) - 1.0
if self.is_dac_enabled() && self.enabled {
let input = (!self.lf_shift & 0x01) as u8 * self.current_volume;
(input as f32 / 7.5) - 1.0
} else {
0.0
}
}
fn clock(&mut self) {