MC_NVRAM_SIZE
if (bus_space_map(sc->sc_bst, ga->ga_offset, MC_NREGS+MC_NVRAM_SIZE,
#define MC_NVRAM_CSUM (MC_NVRAM_START + MC_NVRAM_SIZE - 2)
AcpiGbl_FADT.Century < (MC_NVRAM_START + MC_NVRAM_SIZE))