Begins a basic get/set state API, allowing some actual unit tests, implying an ABCD fix.

OSBindings/Mac/Clock SignalTests/68000Tests.mm

@@ -64,6 +64,14 @@ class RAM68000: public CPU::MC68000::BusHandler {
 			return HalfCycles(0);
 		}
 
+		CPU::MC68000::Processor<RAM68000, true>::State get_processor_state() {
+			return m68000_.get_state();
+		}
+
+		void set_processor_state(const CPU::MC68000::Processor<RAM68000, true>::State &state) {
+			m68000_.set_state(state);
+		}
+
 	private:
 		CPU::MC68000::Processor<RAM68000, true> m68000_;
 		std::vector<uint16_t> ram_;
@@ -85,10 +93,24 @@ class RAM68000: public CPU::MC68000::BusHandler {
 }
 
 - (void)testABCD {
-	_machine->set_program({
-		0xc100		// ABCD D0, D0
-	});
-    _machine->run_for(HalfCycles(400));
+	for(int d = 0; d < 100; ++d) {
+		_machine.reset(new RAM68000());
+		_machine->set_program({
+			0xc100		// ABCD D0, D0
+		});
+
+		auto state = _machine->get_processor_state();
+		const uint8_t bcd_d = ((d / 10) * 16) + (d % 10);
+		state.data[0] = bcd_d;
+		_machine->set_processor_state(state);
+
+		_machine->run_for(Cycles(40 + 6));
+
+		state = _machine->get_processor_state();
+		const uint8_t double_d = (d * 2) % 100;
+		const uint8_t bcd_double_d = ((double_d / 10) * 16) + (double_d % 10);
+		XCTAssert(state.data[0] == bcd_double_d, "%02x + %02x = %02x; should equal %02x", bcd_d, bcd_d, state.data[0], bcd_double_d);
+	}
 }
 
 - (void)testSBCD {

Processors/68000/68000.hpp

@@ -157,12 +157,28 @@ class BusHandler {
 class ProcessorBase: public ProcessorStorage {
 };
 
+struct ProcessorState {
+	uint32_t data[8];
+	uint32_t address[7];
+	uint32_t user_stack_pointer, supervisor_stack_pointer;
+	uint32_t program_counter;
+	uint16_t status;
+
+	// TODO: More state needed to indicate current instruction, the processor's
+	// progress through it, and anything it has fetched so far.
+//			uint16_t current_instruction;
+};
+
 template <class T, bool dtack_is_implicit> class Processor: public ProcessorBase {
 	public:
 		Processor(T &bus_handler) : ProcessorBase(), bus_handler_(bus_handler) {}
 
 		void run_for(HalfCycles duration);
 
+		using State = ProcessorState;
+		State get_state();
+		void set_state(const State &);
+
 	private:
 		T &bus_handler_;
 };

Processors/68000/Implementation/68000Implementation.hpp

@@ -93,7 +93,7 @@ template <class T, bool dtack_is_implicit> void Processor<T, dtack_is_implicit>:
 								int result = (destination & 0xf) + (source & 0xf) + (extend_flag_ ? 1 : 0);
 								if(result > 0x9) result += 0x06;
 								result += (destination & 0xf0) + (source & 0xf0);
-								if(result > 0x90) result += 0x60;
+								if((result&0xff0) > 0x90) result += 0x60;
 
 								// Set all flags essentially as if this were normal addition.
 								zero_flag_ |= result & 0xff;
@@ -114,7 +114,7 @@ template <class T, bool dtack_is_implicit> void Processor<T, dtack_is_implicit>:
 								int result = (destination & 0xf) - (source & 0xf) - (extend_flag_ ? 1 : 0);
 								if(result > 0x9) result -= 0x06;
 								result += (destination & 0xf0) - (source & 0xf0);
-								if(result > 0x90) result -= 0x60;
+								if((result&0xff0) > 0x90) result -= 0x60;
 
 								// Set all flags essentially as if this were normal subtraction.
 								zero_flag_ |= result & 0xff;
@@ -176,3 +176,26 @@ template <class T, bool dtack_is_implicit> void Processor<T, dtack_is_implicit>:
 			}
 	}
 }
+
+template <class T, bool dtack_is_implicit> ProcessorState Processor<T, dtack_is_implicit>::get_state() {
+	write_back_stack_pointer();
+
+	State state;
+	memcpy(state.data, data_, sizeof(state.data));
+	memcpy(state.address, address_, sizeof(state.address));
+	state.user_stack_pointer = stack_pointers_[0].full;
+	state.supervisor_stack_pointer = stack_pointers_[1].full;
+
+	// TODO: status word.
+
+	return state;
+}
+
+template <class T, bool dtack_is_implicit> void Processor<T, dtack_is_implicit>::set_state(const ProcessorState &state) {
+	memcpy(data_, state.data, sizeof(state.data));
+	memcpy(address_, state.address, sizeof(state.address));
+	stack_pointers_[0].full = state.user_stack_pointer;
+	stack_pointers_[1].full = state.supervisor_stack_pointer;
+
+	// TODO: update address[7], once there's a status word to discern the mode this processor should now be in.
+}

Processors/68000/Implementation/68000Storage.cpp

@@ -388,7 +388,7 @@ CPU::MC68000::ProcessorStorage::ProcessorStorage() {
 	ProcessorStorageConstructor constructor(*this);
 
 	// Create the exception programs.
-	const size_t reset_offset = constructor.assemble_program("n- n- n- n- n- nn nF nf nV nv np np");
+	const size_t reset_offset = constructor.assemble_program("n n n n n nn nF nf nV nv np np");
 
 	// Install operations.
 	constructor.install_instructions();
@@ -401,3 +401,16 @@ CPU::MC68000::ProcessorStorage::ProcessorStorage() {
 	effective_address_ = 0;
 	is_supervisor_ = 1;
 }
+
+void CPU::MC68000::ProcessorStorage::write_back_stack_pointer() {
+	stack_pointers_[is_supervisor_] = address_[7];
+}
+
+void CPU::MC68000::ProcessorStorage::set_is_supervisor(bool is_supervisor) {
+	const int new_is_supervisor = is_supervisor ? 1 : 0;
+	if(new_is_supervisor != is_supervisor_) {
+		stack_pointers_[is_supervisor_] = address_[7];
+		is_supervisor_ = new_is_supervisor;
+		address_[7] = stack_pointers_[is_supervisor_];
+	}
+}

Processors/68000/Implementation/68000Storage.hpp

@@ -141,6 +141,12 @@ class ProcessorStorage {
 		MicroOp *active_micro_op_ = nullptr;
 		BusStep *active_step_ = nullptr;
 
+		/// Copies address_[7] to the proper stack pointer based on current mode.
+		void write_back_stack_pointer();
+
+		/// Sets or clears the supervisor flag, ensuring the stack pointer is properly updated.
+		void set_is_supervisor(bool);
+
 	private:
 		friend class ProcessorStorageConstructor;
 };