Some experiments in global microcode compaction

Global microcode compaction is an open problem in firmware engineering. Although Fisher's trace scheduling method may produce significant reductions in the execution time of compacted microcode, it has some drawbacks. There have been four methods. Tree, SRDAG, ITSC , and GDDG, presented recently to mitigate those drawbacks in different ways. The purpose of the research reported in this paper is to evaluate these new methods. In order to do this, we have tested the published algorithms on several unified microcode sequences of two real machines and compared them on the basis of the results of experiments using three criteria: time efficiency, space efficiency, and complexity.