The invention discloses a multi-element
heuristic instruction selecting method for a VLIW
system structure. The method includes the steps of firstly, acquiring all transmittable instructions in the candidate instruction sets of functional units, wherein the transmittable instructions are instructions whose
data dependence instructions are executed; secondly, calculating the multiple
heuristic quantities corresponding to each transmittable instruction in each functional unit, and the
heuristic quantities include the dependence relation quantity between each instruction and the corresponding dependence instruction, the relation quantity of between each instruction and a
processing unit, and the relation quantity between each instruction and the corresponding functional unit; thirdly, sorting the transmittable instructions in each functional unit for multiple times, selecting one heuristic quantity as the sorting comparison quantity according to priority during each sorting, and using the transmittable
instruction sequence after sorting as the instruction selecting object. The multi-element heuristic instruction selecting method has the advantages that the hardware feature between the instructions and the
processing unit and the association between data and the functional units are fully considered aiming at the features of the VLIW
system structure, and the method is reasonable in
instruction selection and high in parallelism.