From af61bbc3e2fb0e0ee6a8f4690bb7ff7d2307c59f Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Tue, 24 Apr 2018 08:29:05 -0700
Subject: [PATCH] Attempts actual performance of the state machine.

---
 Components/DiskII/DiskII.cpp    | 52 ++++++++++++++++++++++++---------
 Components/DiskII/DiskII.hpp    |  5 ++++
 Machines/AppleII/DiskIICard.cpp |  4 +--
 Machines/AppleII/DiskIICard.hpp |  1 -
 4 files changed, 45 insertions(+), 17 deletions(-)

diff --git a/Components/DiskII/DiskII.cpp b/Components/DiskII/DiskII.cpp
index cab110b8c..a7802385c 100644
--- a/Components/DiskII/DiskII.cpp
+++ b/Components/DiskII/DiskII.cpp
@@ -14,26 +14,28 @@ using namespace Apple;
 
 void DiskII::set_control(Control control, bool on) {
 	printf("Set control %d %s\n", control, on ? "on" : "off");
+	// TODO: seeking, motor control.
 }
 
 void DiskII::set_mode(Mode mode) {
 	printf("Set mode %d\n", mode);
-	state_ = (state_ & ~0x08) | ((mode == Mode::Write) ? 0x8 : 0x0);
+	inputs_ = (inputs_ & ~0x08) | ((mode == Mode::Write) ? 0x2: 0x0);
 }
 
 void DiskII::select_drive(int drive) {
 	printf("Select drive %d\n", drive);
+	// TODO: select a drive.
 }
 
 void DiskII::set_data_register(uint8_t value) {
 	printf("Set data register (?)\n");
-	state_ |= 0x4;
+	inputs_ |= 0x1;
 	data_register_ = value;
 }
 
 uint8_t DiskII::get_shift_register() {
-	printf("Get shift register (?)\n");
-	state_ &= ~0x4;
+	printf("[%02x] ", shift_register_);
+	inputs_ &= ~0x1;
 	return shift_register_;
 }
 
@@ -51,20 +53,42 @@ void DiskII::run_for(const Cycles cycles) {
 The bytes in the P6 ROM has the high four bits reversed compared to the BAPD charts, so you will have to reverse them after fetching the byte.
 
 */
+	// TODO: optimise the resting state.
 
-	uint8_t command = 0;
-	switch(command) {
-		case 0x0:	shift_register_ = 0;	break;	// clear
-		case 0x9:	shift_register_ = static_cast<uint8_t>(shift_register_ << 1);			break;	// shift left, bringing in a zero
-		case 0xd:	shift_register_ = static_cast<uint8_t>((shift_register_ << 1) | 1);		break;	// shift left, bringing in a one
-		case 0xa:
-			shift_register_ = (shift_register_ >> 1) | (is_write_protected() ? 0x80 : 0x00);
-		break;	// shift right, bringing in write protected status
-		case 0xb:	shift_register_ = data_register_;				break;	// load
-		default: break;
+	int integer_cycles = cycles.as_int();
+	while(integer_cycles--) {
+		const int address =
+			(inputs_ << 2) |
+			((shift_register_&0x80) >> 6) |
+			((state_&0x2) >> 1) |
+			((state_&0x1) << 7) |
+			((state_&0x4) << 4) |
+			((state_&0x8) << 2);
+		// TODO: add pulse state in bit 4.
+
+		const uint8_t update = state_machine_[static_cast<std::size_t>(address)];
+		state_ = update >> 4;
+		state_ = ((state_ & 0x8) ? 0x1 : 0x0) | ((state_ & 0x4) ? 0x2 : 0x0) | ((state_ & 0x2) ? 0x4 : 0x0) | ((state_ & 0x1) ? 0x8 : 0x0);
+
+		uint8_t command = update & 0xf;
+		switch(command) {
+			case 0x0:	shift_register_ = 0;													break;	// clear
+			case 0x9:	shift_register_ = static_cast<uint8_t>(shift_register_ << 1);			break;	// shift left, bringing in a zero
+			case 0xd:	shift_register_ = static_cast<uint8_t>((shift_register_ << 1) | 1);		break;	// shift left, bringing in a one
+			case 0xb:	shift_register_ = data_register_;										break;	// load
+			case 0xa:
+				shift_register_ = (shift_register_ >> 1) | (is_write_protected() ? 0x80 : 0x00);
+			break;	// shift right, bringing in write protected status
+			default: break;
+		}
 	}
 }
 
 bool DiskII::is_write_protected() {
 	return true;
 }
+
+void DiskII::set_state_machine(const std::vector<uint8_t> &state_machine) {
+	state_machine_ = state_machine;
+	// TODO: shuffle ordering here?
+}
diff --git a/Components/DiskII/DiskII.hpp b/Components/DiskII/DiskII.hpp
index 45155918f..faa845d17 100644
--- a/Components/DiskII/DiskII.hpp
+++ b/Components/DiskII/DiskII.hpp
@@ -10,7 +10,9 @@
 #define DiskII_hpp
 
 #include "../../ClockReceiver/ClockReceiver.hpp"
+
 #include <cstdint>
+#include <vector>
 
 namespace Apple {
 
@@ -33,13 +35,16 @@ class DiskII {
 		uint8_t get_shift_register();
 
 		void run_for(const Cycles cycles);
+		void set_state_machine(const std::vector<uint8_t> &);
 
 	private:
 		uint8_t state_ = 0;
+		uint8_t inputs_ = 0;
 		uint8_t shift_register_ = 0;
 		uint8_t data_register_ = 0;
 
 		bool is_write_protected();
+		std::vector<uint8_t> state_machine_;
 };
 
 }
diff --git a/Machines/AppleII/DiskIICard.cpp b/Machines/AppleII/DiskIICard.cpp
index 38bbb203d..76c8229f8 100644
--- a/Machines/AppleII/DiskIICard.cpp
+++ b/Machines/AppleII/DiskIICard.cpp
@@ -18,7 +18,7 @@ DiskIICard::DiskIICard(const ROMMachine::ROMFetcher &rom_fetcher, bool is_16_sec
 			"state-machine.rom"
 		});
 	boot_ = std::move(*roms[0]);
-	state_machine_ = std::move(*roms[1]);
+	diskii_.set_state_machine(*roms[1]);
 }
 
 void DiskIICard::perform_bus_operation(CPU::MOS6502::BusOperation operation, uint16_t address, uint8_t *value) {
@@ -61,5 +61,5 @@ void DiskIICard::perform_bus_operation(CPU::MOS6502::BusOperation operation, uin
 }
 
 void DiskIICard::run_for(Cycles cycles, int stretches) {
-	diskii_.run_for(cycles);
+	diskii_.run_for(Cycles(cycles.as_int() * 2));
 }
diff --git a/Machines/AppleII/DiskIICard.hpp b/Machines/AppleII/DiskIICard.hpp
index 08b80027a..9213adf52 100644
--- a/Machines/AppleII/DiskIICard.hpp
+++ b/Machines/AppleII/DiskIICard.hpp
@@ -26,7 +26,6 @@ class DiskIICard: public Card {
 
 	private:
 		std::vector<uint8_t> boot_;
-		std::vector<uint8_t> state_machine_;
 		Apple::DiskII diskii_;
 };