EightBit/MC6809/test/Board.cpp
Adrian Conlon dca2e1bb8e Bring the C++ code a little closer to the C# code.
Signed-off-by: Adrian Conlon <Adrian.conlon@gmail.com>
2019-06-02 12:12:04 +01:00

129 lines
3.5 KiB
C++

#include "stdafx.h"
#include "Board.h"
Board::Board(const Configuration& configuration)
: m_configuration(configuration) {}
void Board::raisePOWER() {
EightBit::Bus::raisePOWER();
// Get the CPU ready for action
CPU().raisePOWER();
CPU().lowerRESET();
CPU().raiseINT();
CPU().raiseNMI();
CPU().raiseFIRQ();
CPU().raiseHALT();
// Get the ACIA ready for action
ADDRESS() = 0b1010000000000000;
DATA() = EightBit::mc6850::CR0 | EightBit::mc6850::CR1; // Master reset
ACIA().lower(ACIA().CTS());
ACIA().lower(ACIA().RW());
updateAciaPins();
ACIA().raisePOWER();
accessAcia();
}
void Board::lowerPOWER() {
ACIA().lowerPOWER();
CPU().lowerPOWER();
EightBit::Bus::lowerPOWER();
}
void Board::initialise() {
// Load our BASIC interpreter
const auto directory = m_configuration.getRomDirectory() + "\\";
loadHexFile(directory + "ExBasROM.hex");
// Catch a byte being transmitted
ACIA().Transmitting.connect([this] (EightBit::EventArgs&) {
std::cout << ACIA().TDR();
ACIA().markTransmitComplete();
});
// Marshal data from memory -> ACIA
WrittenByte.connect([this] (EightBit::EventArgs&) {
updateAciaPins();
if (ACIA().selected()) {
ACIA().lower(ACIA().RW());
accessAcia();
}
});
// Marshal data from ACIA -> memory
ReadingByte.connect([this] (EightBit::EventArgs&) {
updateAciaPins();
ACIA().raise(ACIA().RW());
if (accessAcia())
poke(ACIA().DATA());
});
// Keyboard wiring, check for input once per frame
CPU().ExecutedInstruction.connect([this] (EightBit::mc6809& cpu) {
assert(cpu.cycles() > 0);
m_frameCycleCount -= cpu.cycles();
if (m_frameCycleCount < 0) {
if (_kbhit()) {
ACIA().RDR() = _getch();
ACIA().markReceiveStarting();
}
m_frameCycleCount = Configuration::FrameCycleInterval;
}
});
if (m_configuration.isDebugMode()) {
// MC6809 disassembly wiring
CPU().ExecutingInstruction.connect([this] (EightBit::mc6809& cpu) {
m_disassembleAt = cpu.PC();
m_ignoreDisassembly = m_disassembler.ignore();
});
CPU().ExecutedInstruction.connect([this] (EightBit::mc6809&) {
if (!m_ignoreDisassembly)
std::cout << m_disassembler.trace(m_disassembleAt) << " " << ACIA().dumpStatus() << std::endl;
});
}
if (m_configuration.terminatesEarly()) {
// Early termination condition for CPU timing code
CPU().ExecutedInstruction.connect([this] (EightBit::mc6809& cpu) {
assert(cpu.cycles() > 0);
m_totalCycleCount += cpu.cycles();
if (m_totalCycleCount > Configuration::TerminationCycles)
lowerPOWER();
});
}
}
EightBit::MemoryMapping Board::mapping(uint16_t address) {
if (address < 0x8000)
return { m_ram, 0x0000, EightBit::Chip::Mask16, EightBit::MemoryMapping::AccessLevel::ReadWrite };
if (address < 0xa000)
return { m_unused2000, 0x8000, EightBit::Chip::Mask16, EightBit::MemoryMapping::AccessLevel::ReadOnly };
if (address < 0xc000)
return { m_io, 0xa000, EightBit::Chip::Mask16, EightBit::MemoryMapping::AccessLevel::ReadWrite };
return { m_rom, 0xc000, EightBit::Chip::Mask16, EightBit::MemoryMapping::AccessLevel::ReadOnly };
}
void Board::updateAciaPins() {
ACIA().DATA() = DATA();
EightBit::Device::match(ACIA().RS(), ADDRESS().word & EightBit::Chip::Bit0);
EightBit::Device::match(ACIA().CS0(), ADDRESS().word & EightBit::Chip::Bit15);
EightBit::Device::match(ACIA().CS1(), ADDRESS().word & EightBit::Chip::Bit13);
EightBit::Device::match(ACIA().CS2(), ADDRESS().word & EightBit::Chip::Bit14);
}
bool Board::accessAcia() {
ACIA().raise(ACIA().E());
ACIA().tick();
const bool activated = ACIA().activated();
ACIA().lower(ACIA().E());
return activated;
}