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162 lines
4.5 KiB
C++
162 lines
4.5 KiB
C++
//
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// Commodore1540.cpp
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// Clock Signal
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//
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// Created by Thomas Harte on 05/07/2016.
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// Copyright © 2016 Thomas Harte. All rights reserved.
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//
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#include "C1540.hpp"
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#include <string>
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#include "../../../Storage/Disk/Encodings/CommodoreGCR.hpp"
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using namespace Commodore::C1540;
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Machine::Machine() :
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_shift_register(0),
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Storage::DiskDrive(1000000, 4, 300)
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{
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// create a serial port and a VIA to run it
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_serialPortVIA.reset(new SerialPortVIA);
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_serialPort.reset(new SerialPort);
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// attach the serial port to its VIA and vice versa
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_serialPort->set_serial_port_via(_serialPortVIA);
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_serialPortVIA->set_serial_port(_serialPort);
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// set this instance as the delegate to receive interrupt requests from both VIAs
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_serialPortVIA->set_interrupt_delegate(this);
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_driveVIA.set_interrupt_delegate(this);
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_driveVIA.set_delegate(this);
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// set a bit rate
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set_expected_bit_length(Storage::Encodings::CommodoreGCR::length_of_a_bit_in_time_zone(3));
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}
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void Machine::set_serial_bus(std::shared_ptr<::Commodore::Serial::Bus> serial_bus)
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{
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Commodore::Serial::AttachPortAndBus(_serialPort, serial_bus);
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}
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unsigned int Machine::perform_bus_operation(CPU6502::BusOperation operation, uint16_t address, uint8_t *value)
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{
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// static bool log = false;
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// if(operation == CPU6502::BusOperation::ReadOpcode && (address == 0xF3C0)) log = true;
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// if(operation == CPU6502::BusOperation::ReadOpcode && log) printf("%04x\n", address);
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// if(operation == CPU6502::BusOperation::ReadOpcode) printf("%04x\n", address);
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// if(operation == CPU6502::BusOperation::ReadOpcode && (address >= 0xF510 && address <= 0xF553)) printf("%04x\n", address);
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// if(operation == CPU6502::BusOperation::ReadOpcode && (address == 0xE887)) printf("A: %02x\n", get_value_of_register(CPU6502::Register::A));
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/* static bool log = false;
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if(operation == CPU6502::BusOperation::ReadOpcode)
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{
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log = (address >= 0xE85B && address <= 0xE907) || (address >= 0xE9C9 && address <= 0xEA2D);
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if(log) printf("\n%04x: ", address);
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}
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if(log) printf("[%c %04x] ", isReadOperation(operation) ? 'r' : 'w', address);*/
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/*
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Memory map (given that I'm unsure yet on any potential mirroring):
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0x0000–0x07ff RAM
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0x1800–0x180f the serial-port VIA
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0x1c00–0x1c0f the drive VIA
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0xc000–0xffff ROM
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*/
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if(address < 0x800)
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{
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if(isReadOperation(operation))
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*value = _ram[address];
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else
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_ram[address] = *value;
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}
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else if(address >= 0xc000)
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{
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if(isReadOperation(operation))
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*value = _rom[address & 0x3fff];
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}
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else if(address >= 0x1800 && address <= 0x180f)
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{
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if(isReadOperation(operation))
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*value = _serialPortVIA->get_register(address);
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else
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_serialPortVIA->set_register(address, *value);
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}
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else if(address >= 0x1c00 && address <= 0x1c0f)
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{
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if(isReadOperation(operation))
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*value = _driveVIA.get_register(address);
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else
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_driveVIA.set_register(address, *value);
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}
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_serialPortVIA->run_for_half_cycles(2);
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_driveVIA.run_for_half_cycles(2);
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return 1;
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}
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void Machine::set_rom(const uint8_t *rom)
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{
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memcpy(_rom, rom, sizeof(_rom));
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}
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void Machine::run_for_cycles(int number_of_cycles)
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{
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CPU6502::Processor<Machine>::run_for_cycles(number_of_cycles);
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if(_driveVIA.get_motor_enabled()) // TODO: motor speed up/down
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Storage::DiskDrive::run_for_cycles(number_of_cycles);
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}
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#pragma mark - 6522 delegate
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void Machine::mos6522_did_change_interrupt_status(void *mos6522)
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{
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// both VIAs are connected to the IRQ line
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set_irq_line(_serialPortVIA->get_interrupt_line() || _driveVIA.get_interrupt_line());
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}
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#pragma mark - Disk drive
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void Machine::process_input_bit(int value, unsigned int cycles_since_index_hole)
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{
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_shift_register = (_shift_register << 1) | value;
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if((_shift_register & 0x3ff) == 0x3ff)
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{
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_driveVIA.set_sync_detected(true);
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_bit_window_offset = -1; // i.e. this bit isn't the first within a data window, but the next might be
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}
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else
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{
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_driveVIA.set_sync_detected(false);
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}
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_bit_window_offset++;
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if(_bit_window_offset == 8)
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{
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_driveVIA.set_data_input((uint8_t)_shift_register);
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_bit_window_offset = 0;
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if(_driveVIA.get_should_set_overflow())
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{
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set_overflow_line(true);
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}
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}
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else
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set_overflow_line(false);
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}
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// the 1540 does not recognise index holes
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void Machine::process_index_hole() {}
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#pragma mak - Drive VIA delegate
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void Machine::drive_via_did_step_head(void *driveVIA, int direction)
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{
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step(direction);
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}
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void Machine::drive_via_did_set_data_density(void *driveVIA, int density)
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{
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set_expected_bit_length(Storage::Encodings::CommodoreGCR::length_of_a_bit_in_time_zone((unsigned int)density));
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}
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