Address manipulation using indices and tags

A system comprising one or more processors and a non-transitory computer readable storage media embodying instructions coupled to the one or more processors, the one or more processors operable to execute the instructions to:

• generate a first index from one or more bits of a processor program counter, wherein the first index is used to access a branch predictor bimodal table;
• provide a first branch prediction from the bimodal table, based on the first index;
• match the first branch prediction against a plurality of N tables, wherein:
• each of the plurality of N tables contain prior branch histories;
• the branch history in table T(N) is of greater length than the branch history of table T(N-1);
• determine, for each of the plurality of N tables, a number of hits for that table, each hit comprising a match between the prior branch history in that table and the first branch prediction;
• when a number of hits for at least one table is greater than zero, then manipulate a processor address according to one or more predictions from the table that has the greatest number of hits.

One or more non-transitory computer readable storage media embodying instructions and coupled to one or more processors that are operable to execute the instructions to:

• generate a first index from one or more bits of a processor program counter, wherein the first index is used to access a branch predictor bimodal table;
• provide a first branch prediction from the bimodal table, based on the first index;
• match the first branch prediction against a plurality of N tables, wherein:
• each of the plurality of N tables contain prior branch histories;
• the branch history in table T(N) is of greater length than the branch history of table T(N-1);
• determine, for each of the plurality of N tables, a number of hits for that table, each hit comprising a match between the prior branch history in that table and the first branch prediction;
• when a number of hits for at least one table is greater than zero, then manipulate a processor address according to one or more predictions from the table that has the greatest number of hits.