mirror of
https://github.com/MoleskiCoder/EightBit.git
synced 2024-09-23 07:54:30 +00:00
124 lines
3.9 KiB
C++
124 lines
3.9 KiB
C++
#include "stdafx.h"
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#include "Board.h"
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Board::Board(const Configuration& configuration)
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: m_configuration(configuration),
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m_cpu(EightBit::mc6809(*this)),
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m_disassembler(*this, m_cpu) {
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}
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void Board::initialise() {
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// Load our BASIC interpreter
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const auto directory = m_configuration.getRomDirectory() + "\\";
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loadHexFile(directory + "ExBasROM.hex");
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// Get the CPU ready for action
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CPU().powerOn();
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CPU().raise(CPU().NMI());
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CPU().raise(CPU().FIRQ());
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CPU().reset();
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// Get the ACIA ready for action
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ADDRESS() = 0b1010000000000000;
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ACIA().DATA() = EightBit::mc6850::CR0 | EightBit::mc6850::CR1; // Master reset
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updateAciaPins(EightBit::Chip::PinLevel::Low);
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ACIA().lower(ACIA().CTS());
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ACIA().powerOn();
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accessAcia();
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// Once the reset has completed, we can wire the ACIA event handlers...
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ACIA().Transmitting.connect(std::bind(&Board::Acia_Transmitting, this, std::placeholders::_1));
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// Wire bus events...
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WrittenByte.connect(std::bind(&Board::Bus_WrittenByte_Acia, this, std::placeholders::_1));
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ReadingByte.connect(std::bind(&Board::Bus_ReadingByte_Acia, this, std::placeholders::_1));
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// Wire CPU events
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CPU().ExecutedInstruction.connect(std::bind(&Board::Cpu_ExecutedInstruction_Acia, this, std::placeholders::_1));
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if (m_configuration.isDebugMode()) {
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CPU().ExecutingInstruction.connect(std::bind(&Board::Cpu_ExecutingInstruction_Debug, this, std::placeholders::_1));
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CPU().ExecutedInstruction.connect(std::bind(&Board::Cpu_ExecutedInstruction_Debug, this, std::placeholders::_1));
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}
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if (m_configuration.terminatesEarly())
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CPU().ExecutedInstruction.connect(std::bind(&Board::Cpu_ExecutedInstruction_Terminator, this, std::placeholders::_1));
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}
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void Board::Cpu_ExecutingInstruction_Debug(EightBit::mc6809&) {
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m_disassembleAt = CPU().PC();
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m_ignoreDisassembly = m_disassembler.ignore();
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}
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void Board::Cpu_ExecutedInstruction_Debug(EightBit::mc6809&) {
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if (!m_ignoreDisassembly)
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std::cout << m_disassembler.trace(m_disassembleAt) << " " << ACIA().dumpStatus() << std::endl;
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}
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EightBit::MemoryMapping Board::mapping(uint16_t address) {
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if (address < 0x8000)
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return { m_ram, 0x0000, 0xffff, EightBit::MemoryMapping::ReadWrite };
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if (address < 0xa000)
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return { m_unused2000, 0x8000, 0xffff, EightBit::MemoryMapping::ReadOnly };
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if (address < 0xc000)
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return { m_io, 0xa000, 0xffff, EightBit::MemoryMapping::ReadWrite };
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return { m_rom, 0xc000, 0xffff, EightBit::MemoryMapping::ReadOnly };
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}
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void Board::Bus_WrittenByte_Acia(EightBit::EventArgs&) {
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updateAciaPins(EightBit::Chip::Low);
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if (ACIA().selected()) {
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ACIA().DATA() = peek(ADDRESS());
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accessAcia();
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}
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}
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void Board::Bus_ReadingByte_Acia(EightBit::EventArgs&) {
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updateAciaPins(EightBit::Chip::High);
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if (accessAcia())
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poke(ADDRESS(), ACIA().DATA());
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}
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void Board::updateAciaPins(const EightBit::Chip::PinLevel rw) {
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ACIA().RW() = rw;
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ACIA().DATA() = DATA();
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ACIA().match(ACIA().RS(), ADDRESS().word & EightBit::Chip::Bit0);
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ACIA().match(ACIA().CS0(), ADDRESS().word & EightBit::Chip::Bit15);
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ACIA().match(ACIA().CS1(), ADDRESS().word & EightBit::Chip::Bit13);
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ACIA().match(ACIA().CS2(), ADDRESS().word & EightBit::Chip::Bit14);
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}
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void Board::Cpu_ExecutedInstruction_Terminator(EightBit::mc6809&) {
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assert(CPU().cycles() > 0);
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m_totalCycleCount += CPU().cycles();
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if (m_totalCycleCount > Configuration::TerminationCycles)
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CPU().powerOff();
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}
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void Board::Cpu_ExecutedInstruction_Acia(EightBit::mc6809&) {
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assert(CPU().cycles() > 0);
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m_frameCycleCount -= CPU().cycles();
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if (m_frameCycleCount < 0) {
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if (_kbhit()) {
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ACIA().RDR() = _getch();
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ACIA().markReceiveStarting();
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}
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m_frameCycleCount = Configuration::FrameCycleInterval;
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}
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}
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void Board::Acia_Transmitting(EightBit::EventArgs&) {
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std::cout << ACIA().TDR();
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ACIA().markTransmitComplete();
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}
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bool Board::accessAcia() {
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ACIA().raise(ACIA().E());
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const bool accessed = ACIA().tick();
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ACIA().lower(ACIA().E());
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return accessed;
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}
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