Indexing entries of a storage structure shared between multiple threads

An apparatus comprising:

• means for processing instructions from a plurality of threads;
• means for prediction storage shared between the plurality of threads and comprising a plurality of entries for storing information for controlling speculative processing by the means for processing;
• and
• means for mapping a received input value associated with a request from the means for processing to a modified input value for supply to the means for prediction storage;
• wherein the means for mapping is configured to generate the modified input value as a function of the received input value and a key value selected depending on which of the plurality of threads triggered the request.

A data processing method comprising:

• processing instructions from a plurality of threads on processing circuitry;
• storing, in a plurality of entries of a predictive storage structure shared between the plurality of threads, information for controlling speculative processing by the processing circuitry;
• and
• mapping a received input value associated with a request from the processing circuitry to a modified input value for supply to the predictive storage structure;
• wherein the modified input value is generated as a function of the received input value and a key value selected depending on which of the plurality of threads triggered the request.