Systems, methods, and apparatuses for last branch record support compatible with binary translation and speculative execution using an architectural bit array and a write bit array

摘要

Systems, methods, and apparatuses for last branch record support are described. In an embodiment, a hardware processor core comprises a hardware execution unit to execute a branch instruction, at least two last branch record (LBR) registers to store a source and destination information of a branch taken during program execution, wherein an entry in a LBR register is to include an encoding of the branch, a write bit array to indicate which LBR register is architecturally correct, an architectural bit array to indicate when an LBR register has been written, and a plurality of top of stack pointers to indicate which LBR register in a LBR register stack is to be written.