/*
$Id: I8254Generic.java,v 1.2 2012-07-08 10:40:43 user Exp $
 */

package mce.arch;

import mce.Cat;
import mce.Emulation;
import mce.cpu.CPU;
import mce.cpu.CPUPlugin;
import mce.cpu.ResPlugin;
import mce.memory.Memory;
import mce.memory.RAM16;
import mce.tools.ConfigException;
import mce.tools.JDOMUtils;

import java.util.Map;

/**
 * MCE Generic I8254 handler.
 * This module holds a basic handler for I8254 port access.
 */
public class I8254Generic extends RAM16 implements ResPlugin, CPUPlugin, I8254Listener {

    // local references
    private I8254 timer;

    // local variables
    private int freqDivisor;
    private int timerTicksRemaining;

    /**
     * MemoryAccess interface: Get memory access type
     *
     * @return int containing the implemented memory access type (one of Memory.MEMTYPE_* constants)
     */
    public int getMemoryType() {

        return Memory.MEMTYPE_OTHER;
    }

    /**
     * Get subname from memory handler for read operation on the given address
     *
     * @param addr Address for which to get the name
     * @return String containing the name (or null if no name was defined)
     */
    public String getReadMemorySubName(int addr) {

        switch (addr & 3) {
            case 0:
                return "cntr0";
            case 1:
                return "cntr1";
            case 2:
                return "cntr2";
            case 3:
                return "cntr?";
        }
        return null;
    }

    /**
     * Get subname from memory handler for write operation on the given address
     *
     * @param addr Address for which to get the name
     * @return String containing the name (or null if no name was defined)
     */
    public String getWriteMemorySubName(int addr) {

        switch (addr & 3) {
            case 0:
                return "cntr0";
            case 1:
                return "cntr1";
            case 2:
                return "cntr1";
            case 3:
                return "cntrc";
        }
        return null;
    }

    /**
     * Get byte from port memory
     *
     * @param addr int containing the flat port address
     * @return int containing the unsigned byte of the requested port
     */
    public int getByte(int addr) {

        return timer.getPort(addr);
//    System.out.println("I8254 get pc = " + FormatUtils.toHex( cpu.getRegPC(), 4 ) + ", addr = " + FormatUtils.toHex( addr, 4 ) + ", value " + FormatUtils.toHex( value, 2 ) );
//    if( ( addr & 3 ) == 2 )
//      System.out.println("timer = " + timer);
//    return value;
    }

    /**
     * MemoryAccess interface: Set byte to port memory
     *
     * @param addr  int containing the flat port address
     * @param value int containing the unsigned byte
     * @return int containing the spent cpu t-states (in the low byte of the high word)
     */
    public int setByte(int addr, int value) {

//    System.out.println("I8254 set pc = " + FormatUtils.toHex( cpu.getRegPC(), 4 ) + ", addr = " + FormatUtils.toHex( addr, 4 ) + ", value " + FormatUtils.toHex( value, 2 ) );
        timer.setPort(addr, value);
        return 0;
    }

    /**
     * Processes interrupt generation signal from given counter
     *
     * @param counter counter number
     */
    public void processCounterInterrupt(int counter) {
    }

    /**
     * Returns I8254 timer
     *
     * @return working timer object
     */
    public I8254 getTimer() {

        return timer;
    }

    /**
     * Processes specific timer counter
     *
     * @param counter counter number
     * @param ticks   number of ticks
     */
    public void processTimer(int counter, int ticks) {

        timer.processTimer(counter, ticks);
    }

    /**
     * CPUPlugin interface: process routine externally from CPU unit
     *
     * @param ticks number of ticks since last method call
     * @return number of ticks to add to the ticks count
     */
    public int processCPUExternal(int ticks) {

        int timerTicks = ticks * freqDivisor + timerTicksRemaining;
        int timerTicksProcessed = timerTicks >> 10;
        timerTicksRemaining = timerTicks - (timerTicksProcessed << 10);
        if (timerTicksProcessed > 0)
            timer.processTimer(0, timerTicksProcessed);
        return 0;
    }

    /**
     * ResPlugin interface: do reset routine external to CPU unit (called when CPU does a reset)
     *
     * @param ticks number of ticks since last method call
     * @return number of ticks to add to the ticks count
     */
    public int doCPUReset(CPU cpu, int ticks) {

        timer.doCPUReset(cpu, ticks);
        timer.setSignalGate(0, false);
        timer.setSignalGate(1, true);
        timer.setSignalGate(2, true);
        timerTicksRemaining = 0;
        return 0;
    }

    /**
     * Configurable interface: configure according to the given configuration parameters
     *
     * @param emu    Emulation object used as the object resource
     * @param config a Map containing the configuration
     */
    public void configure(Emulation emu, Map<String, Object> config) throws ConfigException {

        // call the ancestor
        super.configure(emu, config);

        // get the frequency divisor for CPU Plugin / counter 0
        String freqVal = JDOMUtils.getStringParam(config, "freq-divisor");
        try {
            if (freqVal == null)
                freqVal = "3.2";
            freqDivisor = (int) ((1F / Float.parseFloat(freqVal)) * 1024);
        } catch (NumberFormatException nfe) {
            throw new ConfigException(this, "freq-divisor", Cat.get("must contain proper timer frequency divisor"));
        }

        // create the counter instance and set gate to true for counters 1,2
        timer = new I8254();
        timer.setSignalGate(0, false);
        timer.setSignalGate(1, true);
        timer.setSignalGate(2, true);
        timer.addListener(this);
    }
}