A loop optimization technique based on scheduling table

摘要

Loop optimization is an important aspect of microcode compaction to minimize execution time. In this paper a new loop optimization technique for horizontal microprograms is presented, which makes use of the cyclic regularity of loops.

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We have extended the concept of reservation table, which is used to develop a pipeline control strategy, so that both data dependencies and resource conflicts are taken into account. Based on the analysis of the extended reservation table, or scheduling table, an optimal schedule can be obtained. The iterations of a loop are then rearranged to form a new loop body, whose length may be greater than that of the original one. But the average initiation latency between iterations is minimal.