MFP_AER
mfp_base[MFP_AER] = ((u_int8_t) (a))
#define mfp_get_aer() (mfp_base[MFP_AER])
#define mfp_bit_set_aer(bits) mfp_bit_set(MFP_AER, (bits))
#define mfp_bit_clear_aer(bits) mfp_bit_clear(MFP_AER, (bits))