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Adds a begin_state template.

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This commit is contained in:
Thomas Harte 2021-12-04 07:20:17 -05:00
parent 57789092c1
commit 42d3bdd373
2 changed files with 59 additions and 25 deletions
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71
Machines/Amiga/Audio.cpp
View File

@ -29,18 +29,7 @@ Audio::Audio(Chipset &chipset, uint16_t *ram, size_t word_size, float output_rat
speaker_.set_input_rate(output_rate);
}
bool Audio::advance_dma(int channel) {
if(!channels_[channel].wants_data) {
return false;
}
set_data(channel, ram_[pointer_[size_t(channel) & ram_mask_]]);
if(channels_[channel].state != Channel::State::WaitingForDummyDMA) {
++pointer_[size_t(channel)];
}
return true;
}
// MARK: - Exposed setters.
void Audio::set_length(int channel, uint16_t length) {
assert(channel >= 0 && channel < 4);
@ -80,6 +69,21 @@ void Audio::set_interrupt_requests(uint16_t requests) {
channels_[3].interrupt_pending = requests & uint16_t(InterruptFlag::AudioChannel3);
}
// MARK: - DMA and mixing.
bool Audio::advance_dma(int channel) {
if(!channels_[channel].wants_data) {
return false;
}
set_data(channel, ram_[pointer_[size_t(channel) & ram_mask_]]);
if(channels_[channel].state != Channel::State::WaitingForDummyDMA) {
++pointer_[size_t(channel)];
}
return true;
}
void Audio::output() {
constexpr InterruptFlag interrupts[] = {
InterruptFlag::AudioChannel0,
@ -133,6 +137,8 @@ void Audio::output() {
}
}
// MARK: - Per-channel logic.
/*
Big spiel on the state machine:
@ -300,13 +306,19 @@ void Audio::output() {
//
// Non-action fallback transition.
// Non-action fallback transition and setter, plus specialised begin_state declarations.
//
template <Audio::Channel::State end> void Audio::Channel::begin_state() {
state = end;
}
template <> void Audio::Channel::begin_state<Audio::Channel::State::PlayingHigh>();
template <> void Audio::Channel::begin_state<Audio::Channel::State::PlayingLow>();
template <
Audio::Channel::State begin,
Audio::Channel::State end> bool Audio::Channel::transit() {
state = end;
begin_state<end>();
return false;
}
@ -317,7 +329,7 @@ template <
template <> bool Audio::Channel::transit<
Audio::Channel::State::Disabled,
Audio::Channel::State::WaitingForDummyDMA>() {
state = State::WaitingForDummyDMA;
begin_state<State::WaitingForDummyDMA>();
period_counter = period; // i.e. percntrld
length_counter = length; // i.e. lencntrld
@ -328,7 +340,7 @@ template <> bool Audio::Channel::transit<
template <> bool Audio::Channel::transit<
Audio::Channel::State::Disabled,
Audio::Channel::State::PlayingHigh>() {
state = State::PlayingHigh;
begin_state<State::PlayingHigh>();
data_latch = data; // i.e. pbufld1
wants_data = true;
@ -359,7 +371,7 @@ template <> bool Audio::Channel::output<Audio::Channel::State::Disabled>() {
template <> bool Audio::Channel::transit<
Audio::Channel::State::WaitingForDummyDMA,
Audio::Channel::State::WaitingForDMA>() {
state = State::WaitingForDMA;
begin_state<State::WaitingForDMA>();
wants_data = true;
if(length == 1) {
@ -389,7 +401,7 @@ template <> bool Audio::Channel::output<Audio::Channel::State::WaitingForDummyDM
template <> bool Audio::Channel::transit<
Audio::Channel::State::WaitingForDMA,
Audio::Channel::State::PlayingHigh>() {
state = State::PlayingHigh;
begin_state<State::PlayingHigh>();
data_latch = data;
wants_data = true;
@ -417,7 +429,7 @@ template <> bool Audio::Channel::output<Audio::Channel::State::WaitingForDMA>()
template <> bool Audio::Channel::transit<
Audio::Channel::State::PlayingHigh,
Audio::Channel::State::PlayingLow>() {
state = State::PlayingLow;
begin_state<State::PlayingLow>();
// TODO: if AUDxAP, then pubfid2
// TODO: if AUDxAP and AUDxON, then AUDxDR
@ -441,6 +453,13 @@ template <> bool Audio::Channel::transit<
return false;
}
template <> void Audio::Channel::begin_state<Audio::Channel::State::PlayingHigh>() {
state = Audio::Channel::State::PlayingHigh;
// Output high byte.
output_level = int8_t(data_latch >> 8);
}
template <> bool Audio::Channel::output<Audio::Channel::State::PlayingHigh>() {
-- period_counter;
@ -450,9 +469,6 @@ template <> bool Audio::Channel::output<Audio::Channel::State::PlayingHigh>() {
return transit<State::PlayingHigh, State::PlayingLow>();
}
// Output high byte.
output_level = int8_t(data_latch >> 8);
return false;
}
@ -463,7 +479,7 @@ template <> bool Audio::Channel::output<Audio::Channel::State::PlayingHigh>() {
template <> bool Audio::Channel::transit<
Audio::Channel::State::PlayingLow,
Audio::Channel::State::PlayingHigh>() {
state = State::PlayingHigh;
begin_state<State::PlayingHigh>();
// TODO: include napnav in tests
@ -484,6 +500,13 @@ template <> bool Audio::Channel::transit<
return false;
}
template <> void Audio::Channel::begin_state<Audio::Channel::State::PlayingLow>() {
state = Audio::Channel::State::PlayingLow;
// Output low byte.
output_level = int8_t(data_latch & 0xff);
}
template <> bool Audio::Channel::output<Audio::Channel::State::PlayingLow>() {
-- period_counter;
@ -497,8 +520,6 @@ template <> bool Audio::Channel::output<Audio::Channel::State::PlayingLow>() {
return transit<State::PlayingLow, State::PlayingHigh>();
}
// Output low byte.
output_level = int8_t(data_latch & 0xff);
return false;
}

13
Machines/Amiga/Audio.hpp
View File

@ -100,10 +100,23 @@ class Audio: public DMADevice<4> {
PlayingLow, // 011
} state = State::Disabled;
/// Dispatches to the appropriate templatised output for the current state.
/// @returns @c true if an interrupt should be posted; @c false otherwise.
bool output();
/// Applies dynamic logic for @c state, mostly testing for potential state transitions.
/// @returns @c true if an interrupt should be posted; @c false otherwise.
template <State state> bool output();
/// Transitions from @c begin to @c end, calling the appropriate @c begin_state
/// and taking any steps specific to that particular transition.
/// @returns @c true if an interrupt should be posted; @c false otherwise.
template <State begin, State end> bool transit();
/// Begins @c state, performing all fixed logic that would otherwise have to be
/// repeated endlessly in the relevant @c output.
template <State state> void begin_state();
// Output state.
int8_t output_level = 0;
uint8_t output_phase = 0; // TODO: this should count down, not up.