Functional test guarantees that the circuit is tested under normal conditions, thus avoiding any over-as well as under-test. This work is based on the use of Software-Based-Self-Test that allows a special application of functional test to the processor-based systems. This strategy applies the so-called functional test programs that are executed by the processor to guarantee a given fault coverage. The main goal of this paper is to investigate the static test compaction of a given set of functional test programs. The investigation aims at understanding and determining how to select the best functional test program candidates to obtain the smallest set having the best fault coverage. Results carried out on two different microprocessors show that a 49% reduction in test length and a 28.7% reduction in test application time can be achieved.