Patent ID: 7669038

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 computer program product executable in a computer readable storage medium for selecting an instruction during a particular cycle for issue during the very next cycle following said particular cycle in said succession, said computer program product comprising: program instructions for selecting said particular cycle to be a cycle during which a previously designated instruction is allowed to issue; program instructions for identifying the oldest ready instruction in said queue during said particular cycle; program instructions, operable when an instruction was designated during a previous cycle to issue during said particular cycle, for 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 program instructions for selecting said first instruction for issue during said very next following cycle only if said first instruction complies with each condition in said set.