Mapper203.java

package com.grapeshot.halfnes.mappers;

import com.grapeshot.halfnes.*;

public class Mapper203 extends Mapper {

    @Override
    public void loadrom() throws BadMapperException {
        //needs to be in every mapper. Fill with initial cfg
        super.loadrom();
        for (int i = 0; i < 16; ++i) {
            prg_map[i] = (1024 * i) & (prgsize - 1);
        }
        for (int i = 0; i < 8; ++i) {
            chr_map[i] = (1024 * i) & (chrsize - 1);
        }
    }

    @Override
    public int cartRead(final int addr) {
        return prg[prg_map[((addr & 0x3fff)) >> 10] + ((addr & 0x3fff) & 1023)];
    }

    @Override
    public final void cartWrite(final int addr, final int data) {
        if (addr < 0x8000 || addr > 0xffff) {
            super.cartWrite(addr, data);
            return;
        }
        int prgselect = data >> 2;
        int chrselect = data & 3;

        //remap CHR bank
        for (int i = 0; i < 8; ++i) {
            chr_map[i] = (1024 * (i + 8 * chrselect)) & (chrsize - 1);
        }
        //remap PRG bank
        for (int i = 0; i < 16; ++i) {
            prg_map[i] = (1024 * (i + 16 * prgselect)) & (prgsize - 1);
        }
    }
}