Vdp9938Mmio.java

/*
  Vdp9938Mmio.java

  (c) 2008-2016 Edward Swartz

  All rights reserved. This program and the accompanying materials
  are made available under the terms of the Eclipse Public License v1.0
  which accompanies this distribution, and is available at
  http://www.eclipse.org/legal/epl-v10.html
 */
package v9t9.engine.memory;

import v9t9.common.client.ISettingsHandler;
import v9t9.common.memory.IMemory;
import v9t9.engine.video.v9938.VdpV9938;


/** 
 * V9938 mmio chip entry
 * <p>
 * Models the MSX V9938 card access specified in the DIJIT Systems Advanced Video Processor Card (AVPC) manual
 * @author ejs
 */
public class Vdp9938Mmio extends Vdp9918AMmio {

	private BankedMemoryEntry memoryBank;

	private VdpV9938 v9938;

    public Vdp9938Mmio(ISettingsHandler settings, IMemory memory, VdpV9938 vdp, int memSize) {
    	super(settings, memory, vdp, adjustMemorySize(memSize));
    	this.v9938 = vdp;
    }
    
    private static int adjustMemorySize(int memorySize) {
		if (memorySize < 0x4000)
			memorySize = 0x4000;
		else if (memorySize < 0x20000)
			memorySize = 0x20000;
		else
			memorySize = 0x30000;
		return memorySize;
	}

	protected void initMemory(IMemory memory, int memorySize) {
		memoryBank = new WindowBankedMemoryEntry(
				settings,
				memory, "VDP RAM",
				videoMemory,
				0x0000, 0x4000,
				fullRamArea);
    	this.memoryEntry = memoryBank;
		memory.addAndMap(memoryBank);
    }

	@Override
	protected int getAbsoluteAddress(int vdpaddr) {
		return vdpaddr + (memoryBank.getCurrentBank() << 14);
	}
	
	@Override
	protected void autoIncrementAddr() {
		vdpaddr = vdpaddr+1 & 0x3fff;
		if (vdpaddr == 0 && v9938.isEnhancedMode()) {
			byte vdpbank = (byte) v9938.getRegister(14);
			v9938.setRegister(14, (byte) ((vdpbank + 1) & 0x7));
		}
	}
	
	public void write(int addr, byte val) {
		int port = (addr & 6) >> 1;
    	switch (port) {
    	case 0:
    		writeData(val);
    		break;
    	case 1:
    		writeAddress(val);
    		break;
    	case 2:
			// color data port
    		v9938.writeColorData(val);
			break;
		case 3:
			// indirect data write port
			v9938.writeRegisterIndirect(val);
			break;
    	}
    }

	public BankedMemoryEntry getMemoryBank() {
		return memoryBank;
	}
	
	@Override
	public int getBankAddr() {
		return memoryBank.getCurrentBank() << 14;
	}
	
}