In the research of reconfigurable instruction set processors based on instruction-set extension

the effectiveness of reconfigurable resources utilization will greatly impact the implementation of function units for custom instructions and furthermore performance improvement of the whole system.For the problem

this paper first designs a resource model

which weakens the functions and amounts of reconfigurable resources and mainly provides their types and locations that can calculate utility time.Based on the model

an assignment algorithm for coarse-grained reconfigurable resources is proposed.The algorithm deals with the problem as a multi-coloring graph

and assigns resources for custom instructions through extending graph coloring algorithm in graph theory.Experimental results prove the correctness and effectiveness of the algorithm

and reveal some interesting rules which have guiding significance to improve resource utilization and system performance.