From 8827597363ac5d7c8bb555ea14841b144cd2d003 Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Fri, 8 Jul 2016 19:00:39 -0400
Subject: [PATCH] Messier and messier, but I've at least attempted to implement
 hardware attention acknowledge.

---
 Machines/Commodore/1540/Commodore1540.cpp | 13 +++++++++++-
 Machines/Commodore/1540/Commodore1540.hpp | 25 ++++++++++++++++++-----
 2 files changed, 32 insertions(+), 6 deletions(-)

diff --git a/Machines/Commodore/1540/Commodore1540.cpp b/Machines/Commodore/1540/Commodore1540.cpp
index 335113474..0d803fc6e 100644
--- a/Machines/Commodore/1540/Commodore1540.cpp
+++ b/Machines/Commodore/1540/Commodore1540.cpp
@@ -30,7 +30,14 @@ void Machine::set_serial_bus(std::shared_ptr<::Commodore::Serial::Bus> serial_bu
 
 unsigned int Machine::perform_bus_operation(CPU6502::BusOperation operation, uint16_t address, uint8_t *value)
 {
-//	if(operation == CPU6502::BusOperation::ReadOpcode) printf("%04x\n", address);
+	static bool log = false;
+
+	if(operation == CPU6502::BusOperation::ReadOpcode)
+	{
+		log = (address >= 0xE85B && address <= 0xE907) || (address >= 0xE9C9 && address <= 0xEA2D);
+		 if(log) printf("\n%04x: ", address);
+	}
+	if(log)  printf("[%c %04x] ", isReadOperation(operation) ? 'r' : 'w', address);
 
 	if(address < 0x800)
 	{
@@ -46,6 +53,10 @@ unsigned int Machine::perform_bus_operation(CPU6502::BusOperation operation, uin
 	}
 	else if(address >= 0x1800 && address <= 0x180f)
 	{
+		if(address == 0x1805)
+		{
+			printf("Timer\n");
+		}
 		if(isReadOperation(operation))
 			*value = _serialPortVIA->get_register(address);
 		else
diff --git a/Machines/Commodore/1540/Commodore1540.hpp b/Machines/Commodore/1540/Commodore1540.hpp
index f5df4c36e..153dc5b8c 100644
--- a/Machines/Commodore/1540/Commodore1540.hpp
+++ b/Machines/Commodore/1540/Commodore1540.hpp
@@ -20,7 +20,7 @@ class SerialPortVIA: public MOS::MOS6522<SerialPortVIA>, public MOS::MOS6522IRQD
 	public:
 		using MOS6522IRQDelegate::set_interrupt_status;
 
-		SerialPortVIA() : _portB(0x9f), _attention_acknowledge_level(false) {}
+		SerialPortVIA() : _portB(0x00), _attention_acknowledge_level(false), _attention_level_input(true), _data_level_output(false) {}
 
 		uint8_t get_port_input(Port port) {
 			if(port) {
@@ -37,10 +37,10 @@ class SerialPortVIA: public MOS::MOS6522<SerialPortVIA>, public MOS::MOS6522IRQD
 					printf("1540 output: %02x\n", value);
 					// "ATNA (Attention Acknowledge) is an output from PB4 which is sensed on the serial data line after being exclusively "ored" by the attention line and inverted"
 					_attention_acknowledge_level = !(value&0x10);
-					serialPort->set_output(::Commodore::Serial::Line::Clock, (::Commodore::Serial::LineLevel)!(value&0x08));
-					serialPort->set_output(::Commodore::Serial::Line::Data, (::Commodore::Serial::LineLevel)!(value&0x02));
+					_data_level_output = (value&0x02);
 
-//					serialPort->set_output(::Commodore::Serial::Line::Data, _attention_acknowledge_level )
+					serialPort->set_output(::Commodore::Serial::Line::Clock, (::Commodore::Serial::LineLevel)!(value&0x08));
+					update_data_line();
 				}
 //				printf("1540 serial port VIA port B: %02x\n", value);
 			}
@@ -56,8 +56,10 @@ class SerialPortVIA: public MOS::MOS6522<SerialPortVIA>, public MOS::MOS6522IRQD
 				case ::Commodore::Serial::Line::Clock:		_portB = (_portB & ~0x04) | (value ? 0x00 : 0x04);		break;
 				case ::Commodore::Serial::Line::Attention:
 					// "ATN (Attention) is an input on pin 3 of P2 and P3 that is sensed at PB7 and CA1 of UC3 after being inverted by UA1"
+					_attention_level_input = !value;
 					_portB = (_portB & ~0x80) | (value ? 0x00 : 0x80);
 					set_control_line_input(Port::A, Line::One, !value);
+					update_data_line();
 				break;
 			}
 		}
@@ -69,7 +71,20 @@ class SerialPortVIA: public MOS::MOS6522<SerialPortVIA>, public MOS::MOS6522IRQD
 	private:
 		uint8_t _portB;
 		std::weak_ptr<::Commodore::Serial::Port> _serialPort;
-		bool _attention_acknowledge_level;
+		bool _attention_acknowledge_level, _attention_level_input, _data_level_output;
+
+		void update_data_line()
+		{
+			std::shared_ptr<::Commodore::Serial::Port> serialPort = _serialPort.lock();
+			if(serialPort) {
+				serialPort->set_output(::Commodore::Serial::Line::Data,
+					(::Commodore::Serial::LineLevel)!(_data_level_output
+					|| (_attention_level_input == _attention_acknowledge_level))
+					);
+
+//
+ 			}
+		}
 };
 
 class DriveVIA: public MOS::MOS6522<DriveVIA>, public MOS::MOS6522IRQDelegate {