Ensures all parts of the Electron have a fully-defined initial state.

Specifically to resolve an error with shift being pressed at startup due to a failure to establish a default value for that flag, but applying the same principle across the board.

Machines/Electron/Electron.cpp

@@ -30,13 +30,7 @@ class ConcreteMachine:
 	public Tape::Delegate,
 	public Utility::TypeRecipient {
 	public:
-		ConcreteMachine() :
-				m6502_(*this),
-				interrupt_control_(0),
-				interrupt_status_(Interrupt::PowerOnReset | Interrupt::TransmitDataEmpty | 0x80),
-				cycles_since_audio_update_(0),
-				use_fast_tape_hack_(false),
-				cycles_until_display_interrupt_(0) {
+		ConcreteMachine() : m6502_(*this) {
 			memset(key_states_, 0, sizeof(key_states_));
 			for(int c = 0; c < 16; c++)
 				memset(roms_[c], 0xff, 16384);
@@ -435,39 +429,41 @@ class ConcreteMachine:
 
 		// Things that directly constitute the memory map.
 		uint8_t roms_[16][16384];
-		bool rom_write_masks_[16];
+		bool rom_write_masks_[16] = {false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false};
 		uint8_t os_[16384], ram_[32768];
 		std::vector<uint8_t> dfs_, adfs_;
 
 		// Paging
-		ROMSlot active_rom_;
-		bool keyboard_is_active_, basic_is_active_;
+		ROMSlot active_rom_ = ROMSlot::ROMSlot0;
+		bool keyboard_is_active_ = false;
+		bool basic_is_active_ = false;
 
 		// Interrupt and keyboard state
-		uint8_t interrupt_status_, interrupt_control_;
+		uint8_t interrupt_status_ = Interrupt::PowerOnReset | Interrupt::TransmitDataEmpty | 0x80;
+		uint8_t interrupt_control_ = 0;
 		uint8_t key_states_[14];
 
 		// Counters related to simultaneous subsystems
-		Cycles cycles_since_display_update_;
-		Cycles cycles_since_audio_update_;
-		int cycles_until_display_interrupt_;
-		Interrupt next_display_interrupt_;
-		VideoOutput::Range video_access_range_;
+		Cycles cycles_since_display_update_ = 0;
+		Cycles cycles_since_audio_update_ = 0;
+		int cycles_until_display_interrupt_ = 0;
+		Interrupt next_display_interrupt_ = Interrupt::RealTimeClock;
+		VideoOutput::Range video_access_range_ = {0, 0xffff};
 
 		// Tape
 		Tape tape_;
-		bool use_fast_tape_hack_;
-		bool fast_load_is_in_data_;
+		bool use_fast_tape_hack_ = false;
+		bool fast_load_is_in_data_ = false;
 
 		// Disk
 		std::unique_ptr<Plus3> plus3_;
-		bool is_holding_shift_;
-		int shift_restart_counter_;
+		bool is_holding_shift_ = false;
+		int shift_restart_counter_ = 0;
 
 		// Outputs
 		std::unique_ptr<VideoOutput> video_output_;
 		std::shared_ptr<Speaker> speaker_;
-		bool speaker_is_enabled_;
+		bool speaker_is_enabled_ = false;
 };
 
 }

Machines/Electron/Plus3.cpp

@@ -10,7 +10,7 @@
 
 using namespace Electron;
 
-Plus3::Plus3() : WD1770(P1770), last_control_(0) {
+Plus3::Plus3() : WD1770(P1770) {
 	set_control_register(last_control_, 0xff);
 }
 

Machines/Electron/Plus3.hpp

@@ -23,8 +23,8 @@ class Plus3 : public WD::WD1770 {
 	private:
 		void set_control_register(uint8_t control, uint8_t changes);
 		std::shared_ptr<Storage::Disk::Drive> drives_[2];
-		int selected_drive_;
-		uint8_t last_control_;
+		int selected_drive_ = 0;
+		uint8_t last_control_ = 0;
 };
 
 }

Machines/Electron/Speaker.hpp

@@ -25,9 +25,9 @@ class Speaker: public ::Outputs::Filter<Speaker> {
 		static const unsigned int clock_rate_divider = 8;
 
 	private:
-		unsigned int counter_;
-		unsigned int divider_;
-		bool is_enabled_;
+		unsigned int counter_ = 0;
+		unsigned int divider_ = 0;
+		bool is_enabled_ = false;
 };
 
 }

Machines/Electron/Tape.cpp

@@ -10,14 +10,7 @@
 
 using namespace Electron;
 
-Tape::Tape() :
-		TapePlayer(2000000),
-		is_running_(false),
-		data_register_(0),
-		delegate_(nullptr),
-		output_({.bits_remaining_until_empty = 0, .cycles_into_pulse = 0}),
-		last_posted_interrupt_status_(0),
-		interrupt_status_(0) {
+Tape::Tape() : TapePlayer(2000000) {
 	shifter_.set_delegate(this);
 }
 

Machines/Electron/Tape.hpp

@@ -53,21 +53,22 @@ class Tape:
 
 		struct {
 			int minimum_bits_until_full;
-		} input_;
+		} input_ = {0};
 		struct {
 			unsigned int cycles_into_pulse;
 			unsigned int bits_remaining_until_empty;
-		} output_;
+		} output_ = {.bits_remaining_until_empty = 0, .cycles_into_pulse = 0};
 
-		bool is_running_;
-		bool is_enabled_;
-		bool is_in_input_mode_;
+		bool is_running_ = false;
+		bool is_enabled_ = false;
+		bool is_in_input_mode_ = false;
 
 		inline void evaluate_interrupts();
-		uint16_t data_register_;
+		uint16_t data_register_ = 0;
 
-		uint8_t interrupt_status_, last_posted_interrupt_status_;
-		Delegate *delegate_;
+		uint8_t interrupt_status_ = 0;
+		uint8_t last_posted_interrupt_status_ = 0;
+		Delegate *delegate_ = nullptr;
 
 		::Storage::Tape::Acorn::Shifter shifter_;
 };

Machines/Electron/Video.cpp

@@ -36,13 +36,7 @@ namespace {
 
 #pragma mark - Lifecycle
 
-VideoOutput::VideoOutput(uint8_t *memory) :
-		ram_(memory),
-		current_pixel_line_(-1),
-		output_position_(0),
-		screen_mode_(6),
-		screen_map_pointer_(0),
-		cycles_into_draw_action_(0) {
+VideoOutput::VideoOutput(uint8_t *memory) : ram_(memory) {
 	memset(palette_, 0xf, sizeof(palette_));
 	setup_screen_map();
 	setup_base_address();

Machines/Electron/Video.hpp

@@ -80,12 +80,13 @@ class VideoOutput {
 		inline void output_pixels(unsigned int number_of_cycles);
 		inline void setup_base_address();
 
-		int output_position_, unused_cycles_;
+		int output_position_ = 0;
+		int unused_cycles_ = 0;
 
 		uint8_t palette_[16];
-		uint8_t screen_mode_;
-		uint16_t screen_mode_base_address_;
-		uint16_t start_screen_address_;
+		uint8_t screen_mode_ = 6;
+		uint16_t screen_mode_base_address_ = 0;
+		uint16_t start_screen_address_ = 0;
 
 		uint8_t *ram_;
 		struct {
@@ -97,14 +98,18 @@ class VideoOutput {
 		} palette_tables_;
 
 		// Display generation.
-		uint16_t start_line_address_, current_screen_address_;
-		int current_pixel_line_, current_pixel_column_, current_character_row_;
-		uint8_t last_pixel_byte_;
-		bool is_blank_line_;
+		uint16_t start_line_address_ = 0;
+		uint16_t current_screen_address_ = 0;
+		int current_pixel_line_ = -1;
+		int current_pixel_column_ = 0;
+		int current_character_row_ = 0;
+		uint8_t last_pixel_byte_ = 0;
+		bool is_blank_line_ = false;
 
 		// CRT output
-		uint8_t *current_output_target_, *initial_output_target_;
-		unsigned int current_output_divider_;
+		uint8_t *current_output_target_ = nullptr;
+		uint8_t *initial_output_target_ = nullptr;
+		unsigned int current_output_divider_ = 1;
 
 		std::shared_ptr<Outputs::CRT::CRT> crt_;
 
@@ -119,8 +124,8 @@ class VideoOutput {
 		void setup_screen_map();
 		void emplace_blank_line();
 		void emplace_pixel_line();
-		size_t screen_map_pointer_;
-		int cycles_into_draw_action_;
+		size_t screen_map_pointer_ = 0;
+		int cycles_into_draw_action_ = 0;
 };
 
 }