s = (mcf_fec_state *)qemu_mallocz(sizeof(mcf_fec_state));
s->irq = irq;
- s->mmio_index = cpu_register_io_memory(0, mcf_fec_readfn,
+ s->mmio_index = cpu_register_io_memory(mcf_fec_readfn,
mcf_fec_writefn, s);
cpu_register_physical_memory(base, 0x400, s->mmio_index);