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https://github.com/TomHarte/CLK.git
synced 2024-12-24 12:30:17 +00:00
Attempted to move to more accurate bus reading — if control lines are set then all subsequent data inputs should act according to the current control lines; changes to port input should be reflected live upon readings, etc.
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@ -166,6 +166,8 @@ void AY38910::evaluate_output_volume() {
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);
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}
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#pragma mark - Register manipulation
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void AY38910::select_register(uint8_t r) {
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selected_register_ = r & 0xf;
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}
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@ -227,16 +229,22 @@ uint8_t AY38910::get_register_value() {
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return registers_[selected_register_] | register_masks[selected_register_];
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}
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#pragma mark - Port handling
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uint8_t AY38910::get_port_output(bool port_b) {
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return registers_[port_b ? 15 : 14];
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}
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void AY38910::set_port_input(bool port_b, uint8_t value) {
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registers_[port_b ? 15 : 14] = value;
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update_bus();
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}
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#pragma mark - Bus handling
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void AY38910::set_data_input(uint8_t r) {
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data_input_ = r;
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update_bus();
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}
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uint8_t AY38910::get_data_output() {
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@ -244,25 +252,25 @@ uint8_t AY38910::get_data_output() {
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}
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void AY38910::set_control_lines(ControlLines control_lines) {
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ControlState new_state;
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switch((int)control_lines) {
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default: new_state = Inactive; break;
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default: control_state_ = Inactive; break;
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case (int)(BDIR | BC2 | BC1):
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case BDIR:
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case BC1: new_state = LatchAddress; break;
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case BC1: control_state_ = LatchAddress; break;
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case (int)(BC2 | BC1): new_state = Read; break;
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case (int)(BDIR | BC2): new_state = Write; break;
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case (int)(BC2 | BC1): control_state_ = Read; break;
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case (int)(BDIR | BC2): control_state_ = Write; break;
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}
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// if(new_state != control_state_) {
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control_state_ = new_state;
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switch(new_state) {
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update_bus();
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}
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void AY38910::update_bus() {
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switch(control_state_) {
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default: break;
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case LatchAddress: select_register(data_input_); break;
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case Write: set_register_value(data_input_); break;
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case Read: data_output_ = get_register_value(); break;
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}
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// }
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}
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@ -94,6 +94,8 @@ class AY38910: public ::Outputs::Filter<AY38910> {
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int16_t output_volume_;
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inline void evaluate_output_volume();
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inline void update_bus();
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};
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};
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