public void handler(int lines) {
            UBytePtr RAM = memory_region(REGION_CPU1);

            if (lines >= 0x1c) {
                if (errorlog != null) {
                    fprintf(errorlog, "PC = %04x : Unknown bank selected %02x\n", cpu_get_pc(), lines);
                }
            } else {
                cpu_setbank(1, new UBytePtr(RAM, 0x10000 + (lines * 0x2000)));
            }
        }