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119 lines
2.8 KiB
C++
119 lines
2.8 KiB
C++
//
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// Vic20.cpp
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// Clock Signal
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//
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// Created by Thomas Harte on 04/06/2016.
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// Copyright © 2016 Thomas Harte. All rights reserved.
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//
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#include "Vic20.hpp"
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#include <algorithm>
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using namespace Vic20;
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Machine::Machine() :
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_userPortVIA(new UserPortVIA()),
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_keyboardVIA(new KeyboardVIA())
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{
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_userPortVIA->set_delegate(this);
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_keyboardVIA->set_delegate(this);
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set_reset_line(true);
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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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set_reset_line(false);
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// run the phase-1 part of this cycle, in which the VIC accesses memory
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uint16_t video_address = _mos6560->get_address();
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uint8_t video_value = 0xff; // TODO
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if(!(video_address&0x2000))
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{
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video_value = _characterROM[video_address & 0x0fff];
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}
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else
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{
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video_address &= 0x1fff;
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if(video_address < sizeof(_userBASICMemory)) video_value = _userBASICMemory[video_address];
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else if(video_address >= 0x1000 && video_address < 0x2000) video_value = _screenMemory[video_address&0x0fff];
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}
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_mos6560->set_graphics_value(video_value, _colorMemory[video_address & 0x03ff]);
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// run the phase-2 part of the cycle, which is whatever the 6502 said it should be
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if(isReadOperation(operation))
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{
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*value = read_memory(address);
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if((address&0xfff0) == 0x9000)
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{
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*value = _mos6560->get_register(address - 0x9000);
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}
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else if((address&0xfff0) == 0x9110)
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{
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*value = _userPortVIA->get_register(address - 0x9110);
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}
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else if((address&0xfff0) == 0x9120)
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{
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*value = _keyboardVIA->get_register(address - 0x9120);
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}
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}
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else
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{
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uint8_t *ram = ram_pointer(address);
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if(ram) *ram = *value;
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else if((address&0xfff0) == 0x9000)
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{
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_mos6560->set_register(address - 0x9000, *value);
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}
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else if((address&0xfff0) == 0x9110)
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{
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_userPortVIA->set_register(address - 0x9110, *value);
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}
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else if((address&0xfff0) == 0x9120)
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{
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_keyboardVIA->set_register(address - 0x9120, *value);
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}
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}
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_userPortVIA->run_for_cycles(1);
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_keyboardVIA->run_for_cycles(1);
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return 1;
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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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bool irq = _userPortVIA->get_interrupt_line() || _keyboardVIA->get_interrupt_line();
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set_irq_line(irq);
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}
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#pragma mark - Setup
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void Machine::setup_output(float aspect_ratio)
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{
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_mos6560 = std::unique_ptr<MOS::MOS6560>(new MOS::MOS6560());
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}
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void Machine::set_rom(ROMSlot slot, size_t length, const uint8_t *data)
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{
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uint8_t *target = nullptr;
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size_t max_length = 0x2000;
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switch(slot)
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{
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case ROMSlotKernel: target = _kernelROM; break;
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case ROMSlotCharacters: target = _characterROM; max_length = 0x1000; break;
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case ROMSlotBASIC: target = _basicROM; break;
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}
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if(target)
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{
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size_t length_to_copy = std::min(max_length, length);
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memcpy(target, data, length_to_copy);
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}
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}
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void Machine::add_prg(size_t length, const uint8_t *data)
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{
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}
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