| 摘要 |
PURPOSE:To obtain a highly reliable logical operation device, by forming the output of a logical operation circuit all with redundancy. CONSTITUTION:The logical operation circuit ALU gives a logical operation to the first operands A and B to obtain the result C at the output. Through the logical operation, the highest-rank output carry signals Cout and C'out are obtained from the circuit ALU and the parity prediction circuit 2 respectively. These signals are then compared with each other through the exclusive OR gate E1. If a noncoincidence is detected, the parity bit CPa produced by the circuit 2 is inverted by the exclusive OR gate E2 to be delivered in the form of the parity bit cp of the result C. As a result, no error occurs to the bit cp in case an error is detected in the result C. Thus the error of the signal Cout can be detected by the parity check circuit pc. Accordingly, the logical operation device 1a is formed all with the redundancy. |
