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Attempts audio output.

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This commit is contained in:
Thomas Harte 2021-12-01 06:01:58 -05:00
parent a8dd4660b2
commit d23511860d
2 changed files with 24 additions and 5 deletions
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24
Machines/Amiga/Audio.cpp
View File

@ -107,8 +107,15 @@ void Audio::output() {
while(!buffer_available_[buffer_pointer_].load(std::memory_order::memory_order_relaxed));
}
buffer_[buffer_pointer_][sample_pointer_] = 0;
++sample_pointer_;
buffer_[buffer_pointer_][sample_pointer_] = int16_t(
(channels_[0].output_level * channels_[0].output_enabled +
channels_[2].output_level * channels_[2].output_enabled) << 7
);
buffer_[buffer_pointer_][sample_pointer_+1] = int16_t(
(channels_[1].output_level * channels_[1].output_enabled +
channels_[3].output_level * channels_[3].output_enabled) << 7
);
sample_pointer_ += 2;
if(sample_pointer_ == buffer_[buffer_pointer_].size()) {
const auto &buffer = buffer_[buffer_pointer_];
@ -116,7 +123,7 @@ void Audio::output() {
flag.store(false, std::memory_order::memory_order_release);
queue_.enqueue([this, &buffer, &flag] {
speaker_.push(buffer.data(), buffer.size());
speaker_.push(buffer.data(), buffer.size() >> 1);
flag.store(true, std::memory_order::memory_order_relaxed);
});
@ -438,7 +445,8 @@ template <> bool Audio::Channel::output<Audio::Channel::State::PlayingHigh>() {
return transit<State::PlayingHigh, State::PlayingLow>();
}
// TODO: penhi (i.e. output high byte).
// Output high byte.
output_level = data_latch >> 8;
return false;
}
@ -479,7 +487,8 @@ template <> bool Audio::Channel::output<Audio::Channel::State::PlayingLow>() {
return transit<State::PlayingLow, State::PlayingHigh>();
}
// TODO: not penhi (i.e. output low byte).
// Output low byte.
output_level = data_latch & 0xff;
return false;
}
@ -489,6 +498,11 @@ template <> bool Audio::Channel::output<Audio::Channel::State::PlayingLow>() {
//
bool Audio::Channel::output() {
// Update pulse-width modulation.
output_phase = (output_phase + 1) & 63;
output_enabled |= !output_phase;
output_enabled &= output_phase != volume;
switch(state) {
case State::Disabled: return output<State::Disabled>();
case State::WaitingForDummyDMA: return output<State::WaitingForDummyDMA>();

5
Machines/Amiga/Audio.hpp
View File

@ -103,6 +103,11 @@ class Audio: public DMADevice<4> {
bool output();
template <State state> bool output();
template <State begin, State end> bool transit();
// Output state.
uint8_t output_level = 0;
uint8_t output_phase = 0;
bool output_enabled = false;
} channels_[4];
// Transient output state, and its destination.