BARREL SHIFTER OVERFLOW DETECTION CIRCUIT

摘要

PROBLEM TO BE SOLVED: To provide a barrel shifter and a method therefor for reducing the time required for determining whether an overflow state has occurred in the barrel shifter or not. SOLUTION: The barrel shifter overflow detection circuit 10 has a redundant code bit detector 24 for receiving input data and outputting the number of redundant code bits in the input data and a comparator 28 for receiving the number of redundant code bits from the redundant code bit detector 24 as a 1st input and receiving a shift value as a 2nd input, and the comparator 28 compares two inputs 16 and 26 and generates an output 18. That output expresses whether the overflow state occurs inside a barrel shifter 20 or not and the comparator 28 shifts the input data corresponding to the number of bit positions determined by input data 14 and shift values SV and 16.