1. A method of using a multiprocessor computer system having a first processor and a second processor in data communication with each other via a communications buffer, to call and execute an extended function, wherein said extended function is called by programing of said first processor, but executed by said second processor with function arguments transferred from said first processor to said second processor, comprising the steps of: storing a communications program in memory of said first processor, wherein said communications program has a predetermined number of a plurality of different routines for transferring different types of function arguments to said communications buffer, and wherein each routine has an entry point for receiving entry point arguments; providing an application program having a plurality of extended function calls; redefining said extended function call as an entry point call, wherein said entry point call comprises an entry point command, said entry point command representing an entry point of said communications program of a corresponding one of said routines, and an entry point argument, said entry point argument having values representing a function identifier of said extended function and said types of function arguments corresponding to said corresponding one of said routines; using said first processor to execute said application program having said redefined extended function call; using said first processor to execute a selected one of said routines of said communications program at said entry point corresponding to said entry point command in accordance with said entry point argument, such that said function identifier and data represented by said extended function arguments are uploaded to said communications buffer; using said second processor to download said extended function identifier from said communications buffer; using said second processor to select an extended function definition associated with said extended function identifier from memory of said second processor system; using said second processor to pass arguments to said extended function by passing to said extended function a buffer pointer to said communications buffer; and using said second processor to execute said extended function.