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CLK/Components/AY38910/AY38910.hpp
2016-10-23 20:42:49 -04:00

96 lines
2.2 KiB
C++

//
// AY-3-8910.hpp
// Clock Signal
//
// Created by Thomas Harte on 14/10/2016.
// Copyright © 2016 Thomas Harte. All rights reserved.
//
#ifndef AY_3_8910_hpp
#define AY_3_8910_hpp
#include "../../Outputs/Speaker.hpp"
namespace GI {
/*!
Provides emulation of an AY-3-8910 / YM2149, which is a three-channel sound chip with a
noise generator and a volume envelope generator, which also provides two bidirectional
interface ports.
*/
class AY38910: public ::Outputs::Filter<AY38910> {
public:
/// Creates a new AY38910.
AY38910();
/// Sets the clock rate at which this AY38910 will be run.
void set_clock_rate(double clock_rate);
enum ControlLines {
BC1 = (1 << 0),
BC2 = (1 << 1),
BCDIR = (1 << 2)
};
/// Sets the value the AY would read from its data lines if it were not outputting.
void set_data_input(uint8_t r);
/// Gets the value that would appear on the data lines if only the AY is outputting.
uint8_t get_data_output();
/// Sets the
void set_control_lines(ControlLines control_lines);
/*!
Gets the value that would appear on the requested interface port if it were in output mode.
@parameter port_b @c true to get the value for Port B, @c false to get the value for Port A.
*/
uint8_t get_port_output(bool port_b);
// to satisfy ::Outputs::Speaker (included via ::Outputs::Filter; not for public consumption
void get_samples(unsigned int number_of_samples, int16_t *target);
private:
int _selected_register;
uint8_t _registers[16], _output_registers[16];
int _master_divider;
int _tone_periods[3];
int _tone_counters[3];
int _tone_outputs[3];
int _noise_period;
int _noise_counter;
int _noise_shift_register;
int _noise_output;
int _envelope_period;
int _envelope_divider;
int _envelope_position;
int _envelope_shapes[16][32];
int _envelope_overflow_masks[16];
int _volumes[16];
enum ControlState {
Inactive,
LatchAddress,
Read,
Write
} _control_state;
void select_register(uint8_t r);
void set_register_value(uint8_t value);
uint8_t get_register_value();
uint8_t _data_input, _data_output;
int16_t _output_volume;
inline void evaluate_output_volume();
};
};
#endif /* AY_3_8910_hpp */