Device for performing branch target buffer entry prefetching
AssigneeMicrosoft Technology Licensing, LLC
InventorsJulio Gago Alonso, Santiago Galan, Ivan Pizarro
Life of this patent
Estimating the term…
Abstract
A branch prediction device includes a hierarchy of successively slower to access branch target buffers that store branch target buffer entries identifying branch instructions, branch prediction circuitry configured to predict future branch instructions, and a branch target buffer prefetch table coupled to receive candidate entries corresponding to predicted future branch instruction branch target buffer misses, each entry of the candidate entries corresponding to a precursor branch instruction, and to receive predicted precursor branch instructions that trigger promotion of an entry in a branch target buffer of the branch target buffers to a faster branch target buffer of the branch target buffers.
Claims10
A branch prediction device comprising:
- a hierarchy of successively slower to access branch target buffers that store branch target buffer entries identifying branch instructions;
- branch prediction circuitry configured to predict future branch instructions;
- and
- a branch target buffer prefetch table configured to:
- in response to a branch instruction missing from a faster level of the branch target buffers, allocate a candidate entry that stores a reference to a branch target buffer entry corresponding to the branch instruction that missed and identifies a precursor branch instruction that precedes the branch instruction that missed in a sequence of branch predictions;
- and
- trigger promotion of the branch target buffer entry from a slower level branch target buffer to a branch target buffer that is faster when the precursor branch instruction is subsequently encountered.
Dependencies are inferred from the claim text.