Separates the 8272's drive selection signalling from actual drive ownership.

Thereby returns working motor control to the CPC.

Components/8272/i8272.cpp

@@ -119,11 +119,12 @@ void i8272::run_for(Cycles cycles) {
 					// Perform a step.
 					int direction = (drives_[c].target_head_position < drives_[c].head_position) ? -1 : 1;
 					printf("Target %d versus believed %d\n", drives_[c].target_head_position, drives_[c].head_position);
-					drives_[c].drive->step(direction);
+					select_drive(c);
+					get_drive().step(direction);
 					if(drives_[c].target_head_position >= 0) drives_[c].head_position += direction;
 
 					// Check for completion.
-					if(drives_[c].seek_is_satisfied()) {
+					if(seek_is_satisfied(c)) {
 						drives_[c].phase = Drive::CompletedSeeking;
 						drives_seeking_--;
 						break;
@@ -192,12 +193,6 @@ uint8_t i8272::get_register(int address) {
 	}
 }
 
-void i8272::set_disk(std::shared_ptr<Storage::Disk::Disk> disk, int drive) {
-	if(drive < 4 && drive >= 0) {
-		drives_[drive].drive->set_disk(disk);
-	}
-}
-
 #define BEGIN_SECTION()	switch(resume_point_) { default:
 #define END_SECTION()	}
 
@@ -235,7 +230,7 @@ void i8272::set_disk(std::shared_ptr<Storage::Disk::Disk> disk, int drive) {
 #define SET_DRIVE_HEAD_MFM()	\
 	active_drive_ = command_[1]&3;	\
 	active_head_ = (command_[1] >> 2)&1;	\
-	set_drive(drives_[active_drive_].drive);	\
+	select_drive(active_drive_);	\
 	get_drive().set_head((unsigned int)active_head_);	\
 	set_is_double_density(command_[0] & 0x40);
 
@@ -503,7 +498,7 @@ void i8272::posit_event(int event_type) {
 	write_data:
 			printf("Write [deleted] data [%02x %02x %02x %02x ... %02x %02x]\n", command_[2], command_[3], command_[4], command_[5], command_[6], command_[8]);
 
-			if(drives_[active_drive_].drive->get_is_read_only()) {
+			if(get_drive().get_is_read_only()) {
 				SetNotWriteable();
 				goto abort;
 			}
@@ -618,7 +613,7 @@ void i8272::posit_event(int event_type) {
 	// Performs format [/write] track.
 	format_track:
 			printf("Format track\n");
-			if(drives_[active_drive_].drive->get_is_read_only()) {
+			if(get_drive().get_is_read_only()) {
 				SetNotWriteable();
 				goto abort;
 			}
@@ -711,6 +706,7 @@ void i8272::posit_event(int event_type) {
 	seek:
 			{
 				int drive = command_[1]&3;
+				select_drive(drive);
 
 				// Increment the seeking count if this drive wasn't already seeking.
 				if(drives_[drive].phase != Drive::Seeking) {
@@ -740,7 +736,7 @@ void i8272::posit_event(int event_type) {
 				}
 
 				// Check whether any steps are even needed; if not then mark as completed already.
-				if(drives_[drive].seek_is_satisfied()) {
+				if(seek_is_satisfied(drive)) {
 					drives_[drive].phase = Drive::CompletedSeeking;
 					drives_seeking_--;
 				}
@@ -792,12 +788,13 @@ void i8272::posit_event(int event_type) {
 			printf("Sense drive status\n");
 			{
 				int drive = command_[1] & 3;
+				select_drive(drive);
 				result_stack_.push_back(
 					(command_[1] & 7) |	// drive and head number
 					0x08 |				// single sided
-					(drives_[drive].drive->get_is_track_zero() ? 0x10 : 0x00)	|
+					(get_drive().get_is_track_zero() ? 0x10 : 0x00)	|
-					(drives_[drive].drive->get_is_ready() ? 0x20 : 0x00)		|
+					(get_drive().get_is_ready() ? 0x20 : 0x00)		|
-					(drives_[drive].drive->get_is_read_only() ? 0x40 : 0x00)
+					(get_drive().get_is_read_only() ? 0x40 : 0x00)
 				);
 			}
 			goto post_result;
@@ -852,9 +849,9 @@ void i8272::posit_event(int event_type) {
 	END_SECTION()
 }
 
-bool i8272::Drive::seek_is_satisfied() {
+bool i8272::seek_is_satisfied(int drive) {
-	return	(target_head_position == head_position) ||
+	return	(drives_[drive].target_head_position == drives_[drive].head_position) ||
-			(target_head_position == -1 && drive->get_is_track_zero());
+			(drives_[drive].target_head_position == -1 && get_drive().get_is_track_zero());
 }
 
 void i8272::set_dma_acknowledge(bool dack) {

Components/8272/i8272.hpp

@@ -39,10 +39,11 @@ class i8272: public Storage::Disk::MFMController {
 		void set_dma_acknowledge(bool dack);
 		void set_terminal_count(bool tc);
 
-		void set_disk(std::shared_ptr<Storage::Disk::Disk> disk, int drive);
-
 		bool is_sleeping();
 
+	protected:
+		virtual void select_drive(int number) = 0;
+
 	private:
 		// The bus handler, for interrupt and DMA-driven usage.
 		BusHandler &bus_handler_;
@@ -91,24 +92,20 @@ class i8272: public Storage::Disk::MFMController {
 			int steps_taken;
 			int target_head_position;	// either an actual number, or -1 to indicate to step until track zero
 
-			/// @returns @c true if the currently queued-up seek or recalibrate has reached where it should be.
-			bool seek_is_satisfied();
-
 			// Head state.
 			int head_unload_delay[2];
 			bool head_is_loaded[2];
 
-			// The connected drive.
-			std::shared_ptr<Storage::Disk::Drive> drive;
-
 			Drive() :
 				head_position(0), phase(NotSeeking),
-				drive(new Storage::Disk::Drive(8000000, 300)),	// TODO: these constants can't live here.
 				head_is_loaded{false, false},
 				head_unload_delay{0, 0} {};
 		} drives_[4];
 		int drives_seeking_;
 
+		/// @returns @c true if the selected drive, which is number @c drive, can stop seeking.
+		bool seek_is_satisfied(int drive);
+
 		// User-supplied parameters; as per the specify command.
 		int step_rate_time_;
 		int head_unload_time_;

Machines/AmstradCPC/AmstradCPC.cpp

@@ -582,13 +582,25 @@ class KeyboardState: public GI::AY38910::PortHandler {
 class FDC: public Intel::i8272::i8272 {
 	private:
 		Intel::i8272::BusHandler bus_handler_;
+		std::shared_ptr<Storage::Disk::Drive> drive_;
 
 	public:
-		FDC() : i8272(bus_handler_, Cycles(8000000)) {}
+		FDC() :
+			i8272(bus_handler_, Cycles(8000000)),
+			drive_(new Storage::Disk::Drive(8000000, 300)) {
+			set_drive(drive_);
+		}
 
 		void set_motor_on(bool on) {
-			// TODO: should set all motors on, not 8272.hjust the one active drive.
+			drive_->set_motor_on(on);
-			get_drive().set_motor_on(on);
+		}
+
+		void select_drive(int c) {
+			// TODO: support more than one drive.
+		}
+
+		void set_disk(std::shared_ptr<Storage::Disk::Disk> disk, int drive) {
+			drive_->set_disk(disk);
 		}
 };