public void handler(int offset, int data) {
            UBytePtr RAM = memory_region(REGION_CPU1);

            cpu_setbank(1, new UBytePtr(RAM, 0x20000 + 0x1000 * ((data & 0xc0) >> 6)));
            cpu_setbank(2, new UBytePtr(RAM, 0x10000 + 0x0400 * (data & 0x3c)));
        }