CLK/Machines/Atari2600/Atari2600.hpp

//
//  Atari2600.hpp
//  CLK
//
//  Created by Thomas Harte on 14/07/2015.
//  Copyright © 2015 Thomas Harte. All rights reserved.
//

#ifndef Atari2600_cpp
#define Atari2600_cpp

#include "../../Processors/6502/CPU6502.hpp"
#include "../CRTMachine.hpp"
#include <stdint.h>
#include "Atari2600Inputs.h"

namespace Atari2600 {

const unsigned int number_of_upcoming_events = 16;
const unsigned int number_of_recorded_counters = 7;

class Speaker: public ::Outputs::Filter<Speaker> {
	public:
		Speaker();
		~Speaker();

		void set_volume(int channel, uint8_t volume);
		void set_divider(int channel, uint8_t divider);
		void set_control(int channel, uint8_t control);

		void get_samples(unsigned int number_of_samples, int16_t *target);
		void skip_samples(unsigned int number_of_samples);

	private:
		uint8_t _volume[2];
		uint8_t _divider[2];
		uint8_t _control[2];

		int _poly4_counter[2];
		int _poly5_counter[2];
		int _poly9_counter[2];
		int _output_state[2];

		int _divider_counter[2];

		int _pattern_periods[16];
		int _patterns[16][512];
};

class Machine: public CPU6502::Processor<Machine>, public CRTMachine::Machine {

	public:
		Machine();
		~Machine();

		void set_rom(size_t length, const uint8_t *data);
		void switch_region();

		void set_digital_input(Atari2600DigitalInput input, bool state);

		// to satisfy CPU6502::Processor
		unsigned int perform_bus_operation(CPU6502::BusOperation operation, uint16_t address, uint8_t *value);
		void synchronise();

		// to satisfy CRTMachine::Machine
		virtual void setup_output(float aspect_ratio);
		virtual void close_output();
		virtual Outputs::CRT::CRT *get_crt() { return _crt; }
		virtual Outputs::Speaker *get_speaker() { return &_speaker; }
		virtual void run_for_cycles(int number_of_cycles) { CPU6502::Processor<Machine>::run_for_cycles(number_of_cycles); }

	private:
		uint8_t *_rom, *_romPages[4], _ram[128];
		size_t _rom_size;

		// the timer
		unsigned int _piaTimerValue;
		unsigned int _piaTimerShift, _writtenPiaTimerShift;
		uint8_t _piaTimerStatus;

		// playfield registers
		uint8_t _playfieldControl;
		uint8_t _playfieldColour;
		uint8_t _backgroundColour;
		uint8_t _playfield[41];

		// ... and derivatives
		int _ballSize, _missileSize[2];

		// delayed clock events
		enum OutputState {
			Sync,
			Blank,
			ColourBurst,
			Pixel
		};

		struct Event {
			enum Action {
				Playfield			= 1 << 0,
				ResetCounter		= 1 << 1,

				HMoveSetup			= 1 << 2,
				HMoveCompare		= 1 << 3,
				HMoveDecrement		= 1 << 4,
			};
			int updates;

			OutputState state;
			uint8_t playfieldPixel;
			int counter;

			Event() : updates(0), playfieldPixel(0) {}
		} _upcomingEvents[number_of_upcoming_events];
		unsigned int _upcomingEventsPointer;

		// object counters
		struct ObjectCounter {
			int count;			// the counter value, multiplied by four, counting phase
			int pixel;			// for non-sprite objects, a count of cycles since the last counter reset; for sprite objects a count of pixels so far elapsed
			int broad_pixel;	// for sprite objects, a count of cycles since the last counter reset; otherwise unused

			ObjectCounter() : count(0), pixel(0), broad_pixel(0) {}
		} _objectCounter[number_of_recorded_counters][5];
		unsigned int _objectCounterPointer;

		// the latched playfield output
		uint8_t _playfieldOutput, _nextPlayfieldOutput;

		// player registers
		uint8_t _playerColour[2];
		uint8_t _playerReflectionMask[2];
		uint8_t _playerGraphics[2][2];
		uint8_t _playerGraphicsSelector[2];
		bool _playerStart[2];

		// object flags
		bool _hasSecondCopy[2];
		bool _hasThirdCopy[2];
		bool _hasFourthCopy[2];
		uint8_t _objectMotion[5];		// the value stored to this counter's motion register

		// player + missile registers
		uint8_t _playerAndMissileSize[2];

		// missile registers
		uint8_t _missileGraphicsEnable[2];
		bool _missileGraphicsReset[2];

		// ball registers
		uint8_t _ballGraphicsEnable[2];
		uint8_t _ballGraphicsSelector;

		// graphics output
		unsigned int _horizontalTimer;
		bool _vSyncEnabled, _vBlankEnabled;

		// horizontal motion control
		uint8_t _hMoveCounter;
		uint8_t _hMoveFlags;

		// joystick state
		uint8_t _piaDataDirection[2];
		uint8_t _piaDataValue[2];
		uint8_t _tiaInputValue[2];

		// collisions
		uint8_t _collisions[8];

		void output_pixels(unsigned int count);
		uint8_t get_output_pixel();
		void update_timers(int mask);

		// outputs
		Outputs::CRT::CRT *_crt;
		Speaker _speaker;

		// speaker backlog accumlation counter
		unsigned int _cycles_since_speaker_update;
		void update_audio();

		// latched output state
		unsigned int _lastOutputStateDuration;
		OutputState _stateByExtendTime[2][57];
		OutputState *_stateByTime;
		OutputState _lastOutputState;
		uint8_t *_outputBuffer;

		// lookup table for collision reporting
		uint8_t _reportedCollisions[64][8];
		void setup_reported_collisions();
};

}

#endif /* Atari2600_cpp */