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It's still interrupt-deficient, but fills in additional Ensoniq audio generation.

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This commit is contained in:
Thomas Harte 2020-11-26 16:03:28 -05:00
parent 8edb3fcd5f
commit 72884f37c3
2 changed files with 23 additions and 12 deletions
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33
Machines/Apple/AppleIIgs/Sound.cpp
View File

@ -117,7 +117,7 @@ void GLU::run_for(Cycles cycles) {
void GLU::get_samples(std::size_t number_of_samples, std::int16_t *target) {
// Update remote state, generating audio.
generate_audio(number_of_samples, target, output_range_);
generate_audio(number_of_samples, target);
}
void GLU::skip_samples(const std::size_t number_of_samples) {
@ -174,12 +174,9 @@ uint8_t GLU::get_address_high() {
// MARK: - Update logic.
void GLU::generate_audio(size_t number_of_samples, std::int16_t *target, int16_t range) {
(void)number_of_samples;
(void)target;
(void)range;
void GLU::generate_audio(size_t number_of_samples, std::int16_t *target) {
auto next_store = pending_stores_[pending_store_read_].load(std::memory_order::memory_order_acquire);
uint8_t next_amplitude = 255;
for(size_t sample = 0; sample < number_of_samples; sample++) {
// TODO: there's a bit of a hack here where it is assumed that the input clock has been
@ -206,13 +203,22 @@ void GLU::generate_audio(size_t number_of_samples, std::int16_t *target, int16_t
if(remote_.oscillators[c].position & remote_.oscillators[c].overflow_mask) {
remote_.oscillators[c].position = 0;
remote_.oscillators[c].control |= 1;
} else {
output += remote_.oscillators[c].output(remote_.ram_);
}
break;
case 4: // Sync/AM mode.
assert(false);
if(c&1) {
// Oscillator is odd-numbered; it will amplitude-modulate the next voice.
next_amplitude = remote_.oscillators[c].sample(remote_.ram_);
continue;
} else {
// Oscillator is even-numbered; it will 'sync' to the even voice, i.e. any
// time it wraps around, it will reset the next oscillator.
if(remote_.oscillators[c].position & remote_.oscillators[c].overflow_mask) {
remote_.oscillators[c].position &= remote_.oscillators[c].overflow_mask;
remote_.oscillators[c+1].position = 0;
}
}
break;
case 6: // Swap mode; possibly trigger partner, and update sample.
@ -223,11 +229,16 @@ void GLU::generate_audio(size_t number_of_samples, std::int16_t *target, int16_t
remote_.oscillators[c].control |= 1;
remote_.oscillators[c].position = 0;
remote_.oscillators[c^1].control &= ~1;
} else {
output += remote_.oscillators[c].output(remote_.ram_);
}
break;
}
// Don't add output for newly-halted oscillators.
if(remote_.oscillators[c].control&1) continue;
// Append new output.
output += (remote_.oscillators[c].output(remote_.ram_) * next_amplitude) / 255;
next_amplitude = 255;
}
// Maximum total output was 32 channels times a 16-bit range. Map that down.

2
Machines/Apple/AppleIIgs/Sound.hpp
View File

@ -94,7 +94,7 @@ class GLU: public Outputs::Speaker::SampleSource {
// Functions to update an EnsoniqState; these don't belong to the state itself
// because they also access the pending stores (inter alia).
void generate_audio(size_t number_of_samples, std::int16_t *target, int16_t range);
void generate_audio(size_t number_of_samples, std::int16_t *target);
void skip_audio(EnsoniqState &state, size_t number_of_samples);
// Audio-thread state.