PURPOSE: To facilitate the test of an initialized state as against the reset inputs of various registers such as PC, SP, DP and SFR in an information processor which has been made into LSI.

CONSTITUTION: Micro ROM 22 storing a microprogram for special processing for reading and checking data of the various initialized internal registers, an address register 21 generating the address, a switching circuit 5 switching the output of micro ROM for regular instruction execution control 12 and the output of micro ROM for special processing 22, ROM 32 for data processing, in which the initialization expectation value of the internal register is stored, and external control input terminals T1, T2 and T3 for selecting micro ROM for special processing 22 and setting the head address of the microprogram incorporated in an address register 11 are provided.