Patent ID: 7380104

Claim:
In a computer system having an out of order issue queue containing instructions, wherein the issue queue is operated during a succession of cycles to issue instructions during at least some of the cycles, a method for selecting an instruction during a particular cycle for issue during the cycle immediately following said particular cycle in said succession, said method comprising the steps of: selecting said particular cycle to be a cycle during which a previously designated instruction is allowed to issue; identifying the oldest ready instruction in said queue during said particular cycle; when an instruction was designated during a previous cycle to issue during said particular cycle, determining during said particular cycle whether at least a first instruction in said issue queue complies with each condition in a set of conditions, said first instruction complying with a first one of said conditions if it is determined during said particular cycle that said first instruction has a dependency on said designated instruction, and said first instruction complying with a second one of said conditions if it is determined during said particular cycle that said first instruction is older than said oldest ready instruction; and selecting said first instruction for issue during said cycle immediately following said particular cycle only if said first instruction complies with each condition in said set.