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136 lines
3.2 KiB
C++
136 lines
3.2 KiB
C++
//
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// 9918.hpp
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// Clock Signal
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//
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// Created by Thomas Harte on 25/11/2017.
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// Copyright © 2017 Thomas Harte. All rights reserved.
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//
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#ifndef _918_hpp
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#define _918_hpp
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#include "../../Outputs/CRT/CRT.hpp"
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#include "../../ClockReceiver/ClockReceiver.hpp"
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#include <cstdint>
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namespace TI {
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class TMS9918 {
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public:
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enum Personality {
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TMS9918A, // includes the 9928A; set TV standard as desired.
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};
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/*!
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Constructs an instance of the drive controller that behaves according to personality @c p.
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@param p The type of controller to emulate.
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*/
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TMS9918(Personality p);
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enum TVStandard {
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PAL, NTSC
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};
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void set_tv_standard(TVStandard standard);
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std::shared_ptr<Outputs::CRT::CRT> get_crt();
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/*!
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Runs the VCP for the number of cycles indicate; it is an implicit assumption of the code
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that the input clock rate is 3579545 Hz — the NTSC colour clock rate.
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*/
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void run_for(const HalfCycles cycles);
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void set_register(int address, uint8_t value);
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uint8_t get_register(int address);
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/*!
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Returns the amount of time until get_interrupt_line would next return true if
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there are no interceding calls to set_register or get_register.
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If get_interrupt_line is true now, returns zero. If get_interrupt_line would
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never return true, returns -1.
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*/
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HalfCycles get_time_until_interrupt();
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/*!
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@returns @c true if the interrupt line is currently active; @c false otherwise.
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*/
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bool get_interrupt_line();
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private:
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std::shared_ptr<Outputs::CRT::CRT> crt_;
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uint8_t ram_[16384];
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uint16_t ram_pointer_ = 0;
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uint8_t read_ahead_buffer_ = 0;
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uint8_t status_ = 0;
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bool write_phase_ = false;
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uint8_t low_write_ = 0;
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// The various register flags.
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int next_screen_mode_ = 0, screen_mode_ = 0;
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bool next_blank_screen_ = true, blank_screen_ = true;
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bool sprites_16x16_ = false;
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bool sprites_magnified_ = false;
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bool generate_interrupts_ = false;
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int sprite_height_ = 8;
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uint16_t pattern_name_address_ = 0;
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uint16_t colour_table_address_ = 0;
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uint16_t pattern_generator_table_address_ = 0;
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uint16_t sprite_attribute_table_address_ = 0;
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uint16_t sprite_generator_table_address_ = 0;
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uint8_t text_colour_ = 0;
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uint8_t background_colour_ = 0;
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HalfCycles half_cycles_into_frame_;
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int column_ = 0, row_ = 0, output_column_ = 0;
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int cycles_error_ = 0;
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uint32_t *pixel_target_ = nullptr, *pixel_base_ = nullptr;
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void output_border(int cycles);
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// Vertical timing details.
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int frame_lines_ = 262;
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int first_vsync_line_ = 227;
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// Horizontal selections.
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enum class LineMode {
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Text,
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Character
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} line_mode_ = LineMode::Text;
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int first_pixel_column_, first_right_border_column_;
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uint8_t pattern_names_[40];
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uint8_t pattern_buffer_[40];
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uint8_t colour_buffer_[40];
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struct SpriteSet {
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struct ActiveSprite {
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int index = 0;
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int row = 0;
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uint8_t info[4];
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uint8_t image[2];
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int shift_position = 0;
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} active_sprites[4];
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int active_sprite_slot = 0;
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} sprite_sets_[2];
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int active_sprite_set_ = 0;
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bool sprites_stopped_ = false;
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int access_pointer_ = 0;
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inline void test_sprite(int sprite_number);
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inline void get_sprite_contents(int start, int cycles, int screen_row);
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};
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};
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#endif /* _918_hpp */
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