JPS5719854A - History storing system - Google Patents

Abstract

PURPOSE:To suppress the fact that information in a history storing circuit becomes only a redundant address information by a loop, etc., by suppressing a registration by a history registration controlling circuit, in case when a specific pattern contained in a microinstruction word has been detected. CONSTITUTION:When an address information S1 from an address instructing circuit 4 is address alpha, a microinstruction (a) is read out as a microinstruction word S2 from a microinstruction word memory 3, and the address alpha is registered in a history circuit 2. Subsequently, address beta1 from the circuit 4 is sent to the memory 3 as the address information S1, and a microinstruction b1 is read out from the memory 3. In this case, since an inhibit instruction signal S4 is not outputted from a history registration inhibiting and holding circuit 7, and the address beta1 of the instruction b1 is stored in the circuit 2. Subsequently, when an address beta2 is supplied to the memory 3 from the circuit 4, an instruction b2 is read out, a pattern detection signal S3 is outputted from a specific pattern detecting circuit 5, the signal S4 is outputted from the circuit 7, and it is inhibited to register the address beta2 to the circuit 2.