content: /*
   * HalfNES by Andrew Hoffman
   * Licensed under the GNU GPL Version 3. See LICENSE file
   */
  package com.grapeshot.halfnes.mappers;
  
  //CNROM with copy protection
  public class Mapper185 extends Mapper {
  
      boolean chr_enabled = true;
  
      @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 ppuRead(int addr) {
          if (!chr_enabled) {
              chr_enabled = true;
              return 0x12;
          }
          if (addr < 0x2000) {
              return chr[chr_map[addr >> 10] + (addr & 1023)];
          } else {
              return super.ppuRead(addr);
          }
      }
  
      @Override
      public final void cartWrite(final int addr, final int data) {
          if (addr < 0x8000 || addr > 0xffff) {
              super.cartWrite(addr, data);
              return;
          }
          //remap CHR bank
          for (int i = 0; i < 8; ++i) {
              chr_map[i] = (1024 * (i + 8 * (data & 3))) & (chrsize - 1);
              //copy protection
              chr_enabled = ((chr_map[i] & 0xF) > 0 && (chr_map[i] != 0x13));
          }
      }
  }
  