ksymon/src/main/java/com/loomcom/symon/machines/MichaelBillingtonMachine.java

package com.loomcom.symon.machines;

import com.loomcom.symon.Bus;
import com.loomcom.symon.Cpu;
import com.loomcom.symon.InstructionTable;
import com.loomcom.symon.devices.*;
import com.loomcom.symon.exceptions.MemoryRangeException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.File;

public class MichaelBillingtonMachine implements Machine{

    private static final Logger logger = LoggerFactory.getLogger(MichaelBillingtonMachine.class.getName());

    // Constants used by the simulated system
    private static final int BUS_BOTTOM = 0x0000;
    private static final int BUS_TOP    = 0xffff;

    // 32k of ram, from $0000 to $7fff
    private static final int MEMORY_BASE = 0x0000;
    private static final int MEMORY_SIZE = 0x8000;

    // VIA at $8000-$800f
    private static final int PIA_BASE = 0x8000;

    // ACIA at $8400-$8403
    private static final int ACIA_BASE = 0x8400;

    // 16k ROM from $c000 to $ffff
    private static final int ROM_BASE = 0xc000;
    private static final int ROM_SIZE = 0x4000;

    private final   Bus     bus;
    private final   Cpu     cpu;
    private final   Acia    acia;
    private final   Pia     pia;
    private final   Memory  ram;
    private         Memory  rom;

    public MichaelBillingtonMachine(String romFile) throws Exception {
        this.bus = new Bus(BUS_BOTTOM, BUS_TOP);
        this.cpu = new Cpu();
        this.ram = new Memory(MEMORY_BASE, MEMORY_BASE + MEMORY_SIZE - 1);
        this.pia = new Via6522(PIA_BASE);
        this.acia = new Acia6551(ACIA_BASE);

        bus.addCpu(cpu);
        bus.addDevice(ram);
        bus.addDevice(pia);
        bus.addDevice(acia);

        if (romFile != null) {
            File romImage = new File(romFile);
            if (romImage.canRead()) {
                logger.info("Loading ROM image from file {}", romImage);
                this.rom = Memory.makeROM(ROM_BASE, ROM_BASE + ROM_SIZE - 1, romImage);
            } else {
                logger.info("Default ROM file {} not found, loading empty R/W memory image.", romImage);
                this.rom = Memory.makeRAM(ROM_BASE, ROM_BASE + ROM_SIZE - 1);
            }
        } else {
            logger.info("No ROM file specified, loading empty R/W memory image.");
            this.rom = Memory.makeRAM(ROM_BASE, ROM_BASE + ROM_SIZE - 1);
        }

        bus.addDevice(rom);
    }

    @Override
    public Bus getBus() {
        return bus;
    }

    @Override
    public Cpu getCpu() {
        return cpu;
    }

    @Override
    public Memory getRam() {
        return ram;
    }

    @Override
    public Acia getAcia() {
        return acia;
    }

    @Override
    public Pia getPia() {
        return pia;
    }

    @Override
    public Crtc getCrtc() {
        return null;
    }

    @Override
    public Memory getRom() {
        return rom;
    }

    @Override
    public void setRom(Memory rom) throws MemoryRangeException {
        if (this.rom != null) {
            bus.removeDevice(this.rom);
        }
        this.rom = rom;
        bus.addDevice(this.rom);
    }

    @Override
    public int getRomBase() {
        return ROM_BASE;
    }

    @Override
    public int getRomSize() {
        return ROM_SIZE;
    }

    @Override
    public int getMemorySize() {
        return MEMORY_SIZE;
    }

    @Override
    public String getName() {
        return "mike42";
    }
}