content: package com.grapeshot.halfnes.mappers;
  
  import com.grapeshot.halfnes.*;
  
  public class Mapper246 extends Mapper {
  
      @Override
      public void loadrom() throws BadMapperException {
          //needs to be in every mapper. Fill with initial cfg
          super.loadrom();
          //swappable bank
          for (int i = 0; i < 24; ++i) {
              prg_map[i] = (1024 * i) & (prgsize - 1);
          }
          //fixed bank
          for (int i = 1; i <= 8; ++i) {
              prg_map[32 - i] = prgsize - (1024 * i);
          }
          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 < 0x6000 || addr > 0x67ff) {
              super.cartWrite(addr, data);
              return;
          }
          switch (addr & 7) {
              case 0:
                  for (int i = 0; i < 8; ++i) {
                      prg_map[i] = (1024 * (i + 8 * data)) & (prgsize - 1);
                  }
                  break;
              case 1:
                  for (int i = 0; i < 8; ++i) {
                      prg_map[8 + i] = (1024 * (i + 8 * data)) & (prgsize - 1);
                  }
                  break;
              case 2:
                  for (int i = 0; i < 8; ++i) {
                      prg_map[16 + i] = (1024 * (i + 8 * data)) & (prgsize - 1);
                  }
                  break;
              case 3:
                  for (int i = 0; i < 8; ++i) {
                      prg_map[24 + i] = (1024 * (i + 8 * data)) & (prgsize - 1);
                  }
                  break;
              case 4:
                  for (int i = 0; i < 2; ++i) {
                      chr_map[i] = (1024 * (i + 2 * data)) & (chrsize - 1);
                  }
                  break;
              case 5:
                  for (int i = 0; i < 2; ++i) {
                      chr_map[2 + i] = (1024 * (i + 2 * data)) & (chrsize - 1);
                  }
                  break;
              case 6:
                  for (int i = 0; i < 2; ++i) {
                      chr_map[4 + i] = (1024 * (i + 2 * data)) & (chrsize - 1);
                  }
                  break;
              case 7:
                  for (int i = 0; i < 2; ++i) {
                      chr_map[6 + i] = (1024 * (i + 2 * data)) & (chrsize - 1);
                  }
                  break;
          }
      }
  }
  