Importance

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Abstract

A data processor assigns a unique identifier to each instruction. As there are a finite number of unique identifiers, the identifiers are reused during execution of a program within the data processing system. To maintain an age relationship between instructions executing in the pipeline processor, a methodology is developed to ensure that reused identifiers are properly designated as being younger than their older but larger in magnitude, counterparts. To resolve this issue, assume that the identifier assigned to each instruction has N bits, and therefore, there are 2.sup.N identifiers to be assigned to instructions in the program. The 2.sup.N identifiers are separated into 2.sup.m banks. In addition to assigning identifiers to each instruction, an identifier assignment logic circuit within the pipeline processor provides a global signal that indicates which bank is a youngest bank from which the identifiers are assigned to a remaining portion of the pipeline processor. The global signal preconditions portions of the two identifiers being compared. Subsequently, a result of this conditioning is concatenated with a remaining portion of a selected identifier. The modification of the upper bits of the identifier maintains a relative age position for the identifiers and their associated instructions in the pipelined processor.

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First Claim