The multiplex bit shift device, being the device (50) which runs the data

摘要

PURPOSE: To provide an arithmetic circuit having a carrying function. ;CONSTITUTION: A multiunit shift device 50 of a data processor is provided with a multiplier 55 such as a decoding multipher in an improved booth used for a normal multiplying operation. The multibit shift device 50 executes programming enabling right and left shifts by using the multiplier 55, and saves a circuit area. During the shift operation, a remapping circuit 54 receives the number of times of shift, remaps the number of times of shift according to the shift direction, and provides a remapped signal. The multiplier 55 receives both a shift operand and the remapped signal as the input. The multiplier 55 provides a first shift result as the output. In a certain execution example, an output shifter 57 selectively shifts the first shift result only by a constant amount according to the shift direction, and provides a second shift result. The second shift result includes the outputs of the both right and left shifts at a common bit position.;COPYRIGHT: (C)1995,JPO