/*
* Copyright (c) 2014 Seth J. Morabito <web@loomcom.com>
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
* LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
* OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
package com.loomcom.symon.devices;
import com.loomcom.symon.exceptions.MemoryAccessException;
import com.loomcom.symon.exceptions.MemoryRangeException;
/**
* Very basic implementation of a MOS 6522 VIA.
*
* TODO: Implement timers as threads.
*/
public class Via6522 extends Pia {
public static final int VIA_SIZE = 16;
enum Register {
ORB, ORA, DDRB, DDRA, T1C_L, T1C_H, T1L_L, T1L_H,
T2C_L, T2C_H, SR, ACR, PCR, IFR, IER, ORA_H
}
// Ports A and B
private char[] portData = {0, 0};
private char[] portDirections = {0, 0};
public Via6522(int address) throws MemoryRangeException {
super(address, address + VIA_SIZE - 1, "MOS 6522 VIA");
}
@Override
public void write(int address, int data) throws MemoryAccessException {
Register[] registers = Register.values();
if (address >= registers.length) {
throw new MemoryAccessException("Unknown register: " + address);
}
Register r = registers[address];
switch (r) {
case ORA:
case ORB:
case DDRA:
case DDRB:
case T1C_L:
case T1C_H:
case T1L_L:
case T1L_H:
case T2C_L:
case T2C_H:
case SR:
case ACR:
case PCR:
case IFR:
case IER:
case ORA_H:
default:
}
}
@Override
public int read(int address) throws MemoryAccessException {
Register[] registers = Register.values();
if (address >= registers.length) {
throw new MemoryAccessException("Unknown register: " + address);
}
Register r = registers[address];
switch (r) {
case ORA:
case ORB:
case DDRA:
case DDRB:
case T1C_L:
case T1C_H:
case T1L_L:
case T1L_H:
case T2C_L:
case T2C_H:
case SR:
case ACR:
case PCR:
case IFR:
case IER:
case ORA_H:
default:
}
return 0;
}
}