Patent ID: 9389870
Filing Date: 2016-07-12
CPC Classification: G06F

Claim Text:
1. A method for selecting and issuing an oldest ready instruction in an issue queue, the method comprising: receiving, by one or more processors, one or more instructions into one or more entries in an instruction table in an issue queue; identifying, by one or more processors, instructions that are ready to execute among the one or more instructions in the instruction table with a ready bus; representing, by one or more processors, an age of each of the one or more instructions in the instruction table in a first age array wherein an age of an instruction is an age that is relative to each of the one or more instructions in the first age array; generating, by one or more processors, one or more subsets of the one or more instructions that are associated in one-to-one correspondence with one or more subset age arrays, wherein a subset age array holds a representation of an age of up to 2 instructions in an associated subset that is relative to each of the one or more instructions in the associated subset; generating simultaneously, by one or more processors, i) a first 1-hot signal that identifies an oldest ready instruction with an age represented in the first age array and is identified as ready on the ready bus, and ii) an associated second 1-hot signal that identifies an oldest ready instruction with an age that is represented in the associated subset age array with each subset age array and is identified as ready on the ready bus; selecting, by one or more processors, with each second 1-hot signal, a candidate instruction in the issue queue that is represented in the subset age array that is associated with the second 1-hot signal, wherein a candidate instruction is an oldest ready instruction represented in a subset age array; selecting, by one or more processors, a candidate instruction with the first 1-hot signal; and issuing, by one or more processors, the candidate instruction with the first 1-hot signal.