Patent ID: 8484508

Claim:
A data processing apparatus, comprising: processing circuitry for performing a sequence of data processing operations; a redundant copy of said processing circuitry for operating in parallel with said processing circuitry to perform said sequence of data processing operations; error detection circuitry for detecting an error condition when output data generated by said processing circuitry differs from corresponding output data generated by said redundant copy; and shared prediction circuitry for generating predicted data input to both the processing circuitry and the redundant copy, the processing circuitry and redundant copy arranged to perform speculative processing of one or more of the data processing operations in said sequence in dependence on said predicted data; each of the processing circuitry and said redundant copy including checking circuitry for determining whether the speculative processing was correct, and initiating corrective action if the speculative processing was not correct, wherein said processing circuitry and said redundant copy are configured to generate computed data during performance of said sequence of data processing operations, and the checking circuitry is configured to compare the predicted data with corresponding computed data in order to determine whether the speculative processing was correct.