content: package com.grapeshot.halfnes.mappers;
  
  import com.grapeshot.halfnes.*;
  
  public class Mapper15 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(int addr, int data) {
          if (addr < 0x8000 || addr > 0xffff) {
              super.cartWrite(addr, data);
              return;
          }
  
          int prgbank = (data << 1) & 0xFE;
          int prgflip = data >> 7;
          setmirroring(((data & (utils.BIT6)) != 0) ? MirrorType.H_MIRROR : MirrorType.V_MIRROR);
  
          switch (addr & 0xFFF) {
              case 0x000:
                  for (int i = 0; i < 8; ++i) {
                      prg_map[i] = (1024 * (i + 8 * (prgbank | 0 ^ prgflip))) & (prgsize - 1);
                  }
                  for (int i = 0; i < 8; ++i) {
                      prg_map[8 + i] = (1024 * (i + 8 * (prgbank | 1 ^ prgflip))) & (prgsize - 1);
                  }
                  for (int i = 0; i < 8; ++i) {
                      prg_map[16 + i] = (1024 * (i + 8 * (prgbank | 2 ^ prgflip))) & (prgsize - 1);
                  }
                  for (int i = 0; i < 8; ++i) {
                      prg_map[24 + i] = (1024 * (i + 8 * (prgbank | 3 ^ prgflip))) & (prgsize - 1);
                  }
                  break;
              case 0x001:
                  for (int i = 0; i < 8; ++i) {
                      prg_map[i] = (1024 * (i + 8 * (prgbank | (0 ^ prgflip)))) & (prgsize - 1);
                  }
                  for (int i = 0; i < 8; ++i) {
                      prg_map[8 + i] = (1024 * (i + 8 * (prgbank | (1 ^ prgflip)))) & (prgsize - 1);
                  }
                  for (int i = 0; i < 8; ++i) {
                      prg_map[16 + i] = (1024 * (i + 8 * (0x7E | (0 ^ prgflip)))) & (prgsize - 1);
                  }
                  for (int i = 0; i < 8; ++i) {
                      prg_map[24 + i] = (1024 * (i + 8 * (0x7F | (1 ^ prgflip)))) & (prgsize - 1);
                  }
                  break;
              case 0x002:
                  prgbank |= prgflip;
  
                  for (int i = 0; i < 8; ++i) {
                      prg_map[i] = (1024 * (i + 8 * prgbank)) & (prgsize - 1);
                  }
                  for (int i = 0; i < 8; ++i) {
                      prg_map[8 + i] = (1024 * (i + 8 * prgbank)) & (prgsize - 1);
                  }
                  for (int i = 0; i < 8; ++i) {
                      prg_map[16 + i] = (1024 * (i + 8 * prgbank)) & (prgsize - 1);
                  }
                  for (int i = 0; i < 8; ++i) {
                      prg_map[24 + i] = (1024 * (i + 8 * prgbank)) & (prgsize - 1);
                  }
                  break;
              case 0x003:
                  prgbank |= prgflip;
  
                  for (int i = 0; i < 8; ++i) {
                      prg_map[i] = (1024 * (i + 8 * prgbank)) & (prgsize - 1);
                  }
                  for (int i = 0; i < 8; ++i) {
                      prg_map[8 + i] = (1024 * (i + 8 * (prgbank + 1))) & (prgsize - 1);
                  }
                  for (int i = 0; i < 8; ++i) {
                      prg_map[16 + i] = (1024 * (i + 8 * (prgbank + (~addr >> 1 & 1)))) & (prgsize - 1);
                  }
                  for (int i = 0; i < 8; ++i) {
                      prg_map[24 + i] = (1024 * (i + 8 * (prgbank + 1))) & (prgsize - 1);
                  }
                  break;
              default:
                  break;
          }
      }
  }
  