Managing a Register Cache Based on an Architected Computer Instruction Set Having Operand Last-User Information
AssigneeInternational Business Machines Corporation
InventorsMichael K. Gschwind, Valentina Salapura
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Abstract
A multi-level register hierarchy is disclosed comprising a first level pool of registers for caching registers of a second level pool of registers in a system wherein programs can dynamically release and re-enable architected registers such that released architected registers need not be maintained by the processor, the processor accessing operands from the first level pool of registers, wherein a last-use instruction is identified as having a last use of an architected register before being released, the last-use architected register being released causes the multi-level register hierarchy to discard any correspondence of an entry to said last use architected register.
Claims8
1-14. (canceled)
A computer implemented method for managing a multi-level register hierarchy, comprising a first level pool, of registers for caching registers of a second level pool of registers, the method comprising:
- assigning, by a processor, architected registers to available entries of one of said first level pool or said second level pool, wherein architected registers are defined by an instruction set architecture (ISA) and addressable by register field values of instructions of the ISA, wherein the assigning comprises associating each assigned architected register to a corresponding an entry of a pool of registers;
- moving architected register values to said first level pool from said second level pool according to a first level pool replacement algorithm;
- based on instructions being executed, accessing architected register values of the first level pool of registers corresponding to said architected registers;
- based on executing a last-use instruction for using an architected register identified as a last-use architected register, un-assigning the last-use architected register from both the first level pool and the second level pool, wherein un-assigned entries are available for assigning to architected registers.
Dependencies are inferred from the claim text.