Merge branch 'MSX2' of github.com:TomHarte/CLK into MSX2

Components/9918/Implementation/9918.cpp

@@ -345,14 +345,16 @@ void TMS9918<personality>::run_for(const HalfCycles cycles) {
 					break;
 				}
 
-				next_line_buffer.is_refresh =
-					this->screen_mode_ == ScreenMode::Blank ||
-					this->is_vertical_blank();
+				next_line_buffer.vertical_state =
+					this->screen_mode_ == ScreenMode::Blank ?
+						VerticalState::Blank :
+						this->vertical_state();
+				const bool is_refresh = next_line_buffer.vertical_state == VerticalState::Blank;
 
 				// TODO: an actual sprites-enabled flag.
-				Storage<personality>::begin_line(this->screen_mode_, next_line_buffer.is_refresh, false);
+				Storage<personality>::begin_line(this->screen_mode_, is_refresh, false);
 
-				if(next_line_buffer.is_refresh) {
+				if(is_refresh) {
 					// The Yamaha handles refresh lines via its own microprogram; other VDPs
 					// can fall back on the regular refresh mechanic.
 					if constexpr (is_yamaha_vdp(personality)) {
@@ -425,7 +427,7 @@ void TMS9918<personality>::run_for(const HalfCycles cycles) {
 
 #define border(left, right)	intersect(left, right, this->output_border(end - start, cram_value))
 
-				if(line_buffer.is_refresh) {
+				if(line_buffer.vertical_state != VerticalState::Pixels) {
 					if(
 						this->output_pointer_.row >= this->mode_timing_.first_vsync_line &&
 						this->output_pointer_.row < this->mode_timing_.first_vsync_line + 4
@@ -1036,7 +1038,7 @@ uint8_t Base<personality>::read_register() {
 
 				return
 					transfer_ready |
-					(is_vertical_blank() ? 0x40 : 0x00) |
+					(vertical_state() != VerticalState::Pixels ? 0x40 : 0x00) |
 					(is_horizontal_blank() ? 0x20 : 0x00) |
 					(Storage<personality>::command_ ? 0x01 : 0x00);
 
@@ -1099,8 +1101,11 @@ int Base<personality>::fetch_line() const {
 }
 
 template <Personality personality>
-bool Base<personality>::is_vertical_blank() const {
-	return fetch_pointer_.row >= mode_timing_.pixel_lines && fetch_pointer_.row != mode_timing_.total_lines - 1;
+VerticalState Base<personality>::vertical_state() const {
+	// TODO: the Yamaha uses an internal flag for visible region which toggles at contextually-appropriate moments.
+	// This test won't work properly there.
+	if(fetch_pointer_.row == mode_timing_.total_lines - 1) return VerticalState::Prefetch;
+	return fetch_pointer_.row >= mode_timing_.pixel_lines ? VerticalState::Blank : VerticalState::Pixels;
 }
 
 template <Personality personality>

Components/9918/Implementation/9918Base.hpp

@@ -29,6 +29,16 @@
 namespace TI {
 namespace TMS {
 
+enum class VerticalState {
+	/// Describes any line on which pixels do not appear and no fetching occurs, including
+	/// the border, blanking and sync.
+	Blank,
+	/// A line on which pixels do not appear but fetching occurs.
+	Prefetch,
+	/// A line on which pixels appear and fetching occurs.
+	Pixels,
+};
+
 // Temporary buffers collect a representation of each line prior to pixel serialisation.
 //
 // TODO: either template on personality, to avoid having to be the union of all potential footprints,
@@ -40,7 +50,7 @@ struct LineBuffer {
 	// screen mode captures proper output mode.
 	FetchMode fetch_mode = FetchMode::Text;
 	ScreenMode screen_mode = ScreenMode::Text;
-	bool is_refresh = false;
+	VerticalState vertical_state = VerticalState::Blank;
 
 	// Holds the horizontal scroll position to apply to this line;
 	// of those VDPs currently implemented, affects the Master System only.
@@ -545,8 +555,8 @@ template <Personality personality> struct Base: public Storage<personality> {
 	LineBufferPointer output_pointer_, fetch_pointer_;
 
 	int fetch_line() const;
-	bool is_vertical_blank() const;
 	bool is_horizontal_blank() const;
+	VerticalState vertical_state() const;
 
 	int masked_address(int address) const;
 	void write_vram(uint8_t);

Components/9918/Implementation/AccessEnums.hpp

@@ -42,7 +42,7 @@ enum class ScreenMode {
 constexpr int pixels_per_byte(ScreenMode mode) {
 	switch(mode) {
 		default:
-		case ScreenMode::Blank:				return 0;
+		case ScreenMode::Blank:				return 1;
 		case ScreenMode::Text:				return 6;
 		case ScreenMode::MultiColour:		return 2;
 		case ScreenMode::ColouredText:		return 8;

Components/9918/Implementation/YamahaCommands.hpp

@@ -22,7 +22,7 @@ struct Vector {
 	template <int offset, bool high> void set(uint8_t value) {
 		constexpr uint8_t mask = high ? (offset ? 0x3 : 0x1) : 0xff;
 		constexpr int shift = high ? 8 : 0;
-		v[offset] = (v[offset] & ~(mask << shift)) | (value << shift);
+		v[offset] = (v[offset] & ~(mask << shift)) | ((value & mask) << shift);
 	}
 
 	template <int offset> void add(int amount) {
@@ -258,17 +258,16 @@ struct HighSpeedFill: public Command {
 	}
 
 	bool done() final {
-		return true;
+		return !context.size.v[1] || !width_;
 	}
 
 	void advance(int pixels_per_byte) final {
 		cycles = 48;
 
-		// TODO: step at byte speed, not pixel speed.
 		advance_axis<0>(pixels_per_byte);
-		--context.size.v[0];
+		context.size.v[0] -= pixels_per_byte;
 
-		if(!context.size.v[0]) {
+		if(!(context.size.v[0] & ~(pixels_per_byte - 1))) {
 			cycles += 56;
 			context.size.v[0] = width_;
 			context.destination.v[0] = start_x_;