Fault resilient apparatus and method

An apparatus comprising:

• a storage region comprising a plurality of entries, each entry arranged to store compare data and checksum data for the compare data;
• comparison circuitry responsive to receipt of input data to perform, for each entry within the storage region, a comparison operation comprising comparing at least a portion of the input data with at least a corresponding portion of the compare data stored in that entry to produce a data match indication, and comparing checksum data generated from the input data with the checksum data stored in that entry to produce a checksum match indication;
• and
• evaluation circuitry arranged, for each entry, to evaluate both the data match indication and the checksum match indication in order to produce one of a hit indication, a miss indication and an error indication for that entry.

A method of detecting errors within an apparatus, comprising:

• maintaining in storage a plurality of compare data blocks;
• performing, responsive to receipt of input data, for each compare data block, a processing operation using the input data and the compare data block to produce a match condition indication for that compare data block, the apparatus being configured such that, in expected operation, performance of the processing operation for each compare data block will result in one match condition indication indicating a match, and all other match condition indications indicating absence of a match;
• and
• evaluating the match condition indications produced for the plurality of compare data blocks in order to produce an outcome indication, and in presence of one match condition indication indicating a match, and all other match condition indications indicating absence of a match:
• performing a false hit check procedure in order to check for presence of a false hit;
• and
• in the presence of the false hit producing an error indication as the outcome indication, and otherwise producing a hit indication as the outcome indication.

A method of detecting errors in an apparatus comprising:

• providing a storage region comprising a plurality of entries, where each entry stores compare data and checksum data for the compare data;
• performing, responsive to receipt of input data, for each entry within the storage region, a comparison operation comprising comparing at least a portion of the input data with at least a corresponding portion of the compare data stored in that entry to produce a data match indication, and comparing checksum data generated from the input data with the checksum data stored in that entry to produce a checksum match indication;
• and
• evaluating, for each entry, both the data match indication and the checksum match indication in order to produce one of a hit indication, a miss indication and an error indication for that entry.