Abstract

This paper describes the results of an experiment that empirically evaluated six different schemes for saving and restoring registers on CISC machines. The methods do not require special hardware or inter procedural analysis to be performed. The six schemes were logically divided into two classes. Three of the techniques do not require the compiler to perform data-flow analysis, whereas the other three schemes do. Within each class one scheme delegates the responsibility of preserving the state of the registers to the calling function. The second scheme of each class delegates the responsibility of saving the registers to the function being called. In the third scheme of the two classes, the registers are partitioned into two disjoint sets. The calling function is responsible for preserving register values in one of the sets whereas the called function is responsible for the other set. For each class the third scheme is shown to produce the most effective code

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