Abstract: Systems and methods pertain to a branch target instruction cache (BTIC) of a processor. The BTIC is configured to store one or more branch target instructions at branch target addresses of branch instructions executable by the processor. At least one of the branch target instructions stored in the BTIC is a conditional branch instruction. Branch prediction techniques for predicting the direction of the conditional branch instruction allow one or more instructions following the conditional branch instruction, as well as a branch target address of the conditional branch instruction to also be stored in the BTIC.

Abstract: Systems and methods relate to a hierarchical register file system including a level 1 physical register file (L1 PRF) and a backing physical register file (PRF). A subset of productions of instructions executed in an instruction pipeline of a processor which have a high likelihood of use for one or more future instructions are identified. The subset of productions are stored in the L1 PRF, while all productions are stored in the backing PRF.

Abstract: Indexing subroutine entries in a branch target instruction cache (BTIC) using a target address of the subroutine. The instructions returned by the BTIC may be injected into an execution pipeline to remove a cycle bubble in the processing pipeline.

Abstract: A method and apparatus for allowing an out-of-order processor to reuse an in-use physical register is disclosed herein. The method and apparatus uses identifiers, such as tokens and/or other identifiers in a rename map table (RMT) and a physical register file (PRF), to indicate whether an instruction result is allowed or disallowed to be written into a physical register.

Abstract: Identifying two instructions without intervening potential pipeline flushers that write to the same architected destination register in order to free the physical register corresponding to the older of the two instructions.