content: package com.grapeshot.halfnes.mappers;
  
  import com.grapeshot.halfnes.*;
  
  public class Mapper255 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 < 32; ++i) {
              prg_map[i] = (1024 * i) & (prgsize - 1);
          }
          for (int i = 0; i < 8; ++i) {
              chr_map[i] = (1024 * i) & (chrsize - 1);
          }
      }
  
      @Override
      public final void cartWrite(final int addr, final int data) {
          if (addr < 0x8000 || addr > 0xffff) {
              super.cartWrite(addr, data);
              return;
          }
          final int mode = (~addr >> 12 & 1);
          final int bank = (addr >> 8 & 0x40) | (addr >> 6 & 0x3F);
  
          setmirroring(((addr & 0x2000) != 0) ? MirrorType.H_MIRROR : MirrorType.V_MIRROR);
  
          //remap CHR bank
          for (int i = 0; i < 8; ++i) {
              chr_map[i] = (1024 * (i + 8 * ((addr >> 8 & 0x40) | (addr & 0x3F)))) & (chrsize - 1);
          }
          //remap PRG banks
          for (int i = 0; i < 16; ++i) {
              prg_map[i] = (1024 * (i + 16 * (bank & ~mode))) & (prgsize - 1);
          }
          for (int i = 0; i < 16; ++i) {
              prg_map[16 + i] = (1024 * (i + 16 * (bank | mode))) & (prgsize - 1);
          }
      }
  }
  