MICRO PROCESSOR WITH DECIMAL MULTIPLIER

摘要

PURPOSE:To directly execute the multiplication of the multiplicand data of an integer and multiplier data of a decimal by providing a multiplication control block which sets an arithmetic logical operation means to add data in which a previous addition result is shifted right to multiplicand data. CONSTITUTION:In a micro processor having a decimal multiplier, a multiplication control circuit 41 consisting of a decoder 34 and a bit AND circuit 31 discriminates values for the bits of multiplicand data supplied through a data bus 10 by the signal of a multiplication control circuit 35 and the multiplication control block 30 which drives a switch group 32 by said result and which sets an arithmetic logical operation unit ALU 20 to add data in which the previous addition result is shifted right 33 to multiplicand data supplied from the bus 10 is provided. With such a constitution, multiplicand data of the integer and multiplication data can directly be added and an execution speed can be made faster than a multiplier which deals only integers.