Digital CPU peripheral for calibrating a pseudo-random-number generator, based on the attached paper by Intel "A 4Gbps 0.57pJ/bit Process-Voltage-Temperature Variation Tolerant All-Digital True Random Number Generator in 45nm CMOS: The rng_self_calib controller follows Fig. 7 in the reference paper, generating control bits nconf[3:0] and pconf[3:0] as needed.