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Implements skip_audio.

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This commit is contained in:
Thomas Harte 2020-11-26 16:24:48 -05:00
parent 6f47f9d67c
commit 4870506f6e
2 changed files with 26 additions and 11 deletions
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29
Machines/Apple/AppleIIgs/Sound.cpp
View File

@ -174,6 +174,27 @@ uint8_t GLU::get_address_high() {
// MARK: - Update logic.
void GLU::skip_audio(EnsoniqState &state, size_t number_of_samples) {
// Just advance all oscillator pointers and check for interrupts.
// If a read occurs to the current-output level, generate it then.
for(int c = 0; c < local_.oscillator_count; c++) {
// Don't do anything for halted oscillators.
if(state.oscillators[c].control&1) continue;
// Update phase.
state.oscillators[c].position += state.oscillators[c].velocity * number_of_samples;
// Check for stops, and any interrupts that therefore flow.
if((state.oscillators[c].control & 1) && (state.oscillators[c].position & state.oscillators[c].overflow_mask)) {
// Apply halt, set interrupt request flag.
state.oscillators[c].position = 0;
state.oscillators[c].control |= 1;
state.oscillators[c].interrupt_request = true;
}
}
}
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;
@ -291,11 +312,3 @@ int16_t GLU::EnsoniqState::Oscillator::output(uint8_t *ram) {
// Samples are unsigned 8-bit; do the proper work to make volume work correctly.
return int8_t(level ^ 128) * volume;
}
void GLU::skip_audio(EnsoniqState &state, size_t number_of_samples) {
(void)number_of_samples;
(void)state;
// Just advance all oscillator pointers and check for interrupts.
// If a read occurs to the current-output level, generate it then.
}

4
Machines/Apple/AppleIIgs/Sound.hpp
View File

@ -79,12 +79,14 @@ class GLU: public Outputs::Speaker::SampleSource {
// Derived state.
uint32_t overflow_mask; // If a non-zero bit gets anywhere into the overflow mask, this channel
// has wrapped around. It's a function of table_size.
bool interrupt_request = false; // Will be non-zero if this channel would request an interrupt, were
// it currently enabled to do so.
uint8_t sample(uint8_t *ram);
int16_t output(uint8_t *ram);
} oscillators[32];
// TODO: do all of these need to be on the audio thread?
// Some of these aren't actually needed on both threads.
uint8_t control;
uint8_t interrupt_state;
int oscillator_count;