mirror of
https://github.com/MoleskiCoder/EightBit.git
synced 2024-11-15 21:10:07 +00:00
129 lines
3.5 KiB
C++
129 lines
3.5 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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void Board::raisePOWER() {
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EightBit::Bus::raisePOWER();
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// Get the CPU ready for action
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CPU().raisePOWER();
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CPU().lowerRESET();
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CPU().raiseINT();
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CPU().raiseNMI();
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CPU().raiseFIRQ();
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CPU().raiseHALT();
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// Get the ACIA ready for action
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ADDRESS() = 0b1010000000000000;
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DATA() = EightBit::mc6850::CR0 | EightBit::mc6850::CR1; // Master reset
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ACIA().lower(ACIA().CTS());
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ACIA().lower(ACIA().RW());
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updateAciaPins();
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ACIA().raisePOWER();
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accessAcia();
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}
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void Board::lowerPOWER() {
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ACIA().lowerPOWER();
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CPU().lowerPOWER();
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EightBit::Bus::lowerPOWER();
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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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// Catch a byte being transmitted
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ACIA().Transmitting.connect([this] (EightBit::EventArgs&) {
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std::cout << ACIA().TDR();
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ACIA().markTransmitComplete();
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});
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// Marshal data from memory -> ACIA
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WrittenByte.connect([this] (EightBit::EventArgs&) {
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updateAciaPins();
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if (ACIA().selected()) {
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ACIA().lower(ACIA().RW());
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accessAcia();
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}
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});
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// Marshal data from ACIA -> memory
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ReadingByte.connect([this] (EightBit::EventArgs&) {
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updateAciaPins();
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ACIA().raise(ACIA().RW());
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if (accessAcia())
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poke(ACIA().DATA());
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});
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// Keyboard wiring, check for input once per frame
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CPU().ExecutedInstruction.connect([this] (EightBit::mc6809& cpu) {
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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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if (m_configuration.isDebugMode()) {
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// MC6809 disassembly wiring
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CPU().ExecutingInstruction.connect([this] (EightBit::mc6809& cpu) {
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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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CPU().ExecutedInstruction.connect([this] (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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}
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if (m_configuration.terminatesEarly()) {
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// Early termination condition for CPU timing code
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CPU().ExecutedInstruction.connect([this] (EightBit::mc6809& cpu) {
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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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lowerPOWER();
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});
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}
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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, EightBit::Chip::Mask16, EightBit::MemoryMapping::AccessLevel::ReadWrite };
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if (address < 0xa000)
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return { m_unused2000, 0x8000, EightBit::Chip::Mask16, EightBit::MemoryMapping::AccessLevel::ReadOnly };
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if (address < 0xc000)
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return { m_io, 0xa000, EightBit::Chip::Mask16, EightBit::MemoryMapping::AccessLevel::ReadWrite };
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return { m_rom, 0xc000, EightBit::Chip::Mask16, EightBit::MemoryMapping::AccessLevel::ReadOnly };
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}
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void Board::updateAciaPins() {
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ACIA().DATA() = DATA();
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EightBit::Device::match(ACIA().RS(), ADDRESS().word & EightBit::Chip::Bit0);
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EightBit::Device::match(ACIA().CS0(), ADDRESS().word & EightBit::Chip::Bit15);
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EightBit::Device::match(ACIA().CS1(), ADDRESS().word & EightBit::Chip::Bit13);
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EightBit::Device::match(ACIA().CS2(), ADDRESS().word & EightBit::Chip::Bit14);
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}
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bool Board::accessAcia() {
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ACIA().raise(ACIA().E());
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ACIA().tick();
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const bool activated = ACIA().activated();
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ACIA().lower(ACIA().E());
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return activated;
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}
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