CompiledFunction[args, argregs, nregs, instr, func] represents compiled code for evaluating a compiled function.
args is a list giving a pattern for the type of each argument to the function. The types are specified as in Compile.
argregs is a list of the registers into which actual argument values should be placed to evaluate the compiled code.
nregs is a list of the numbers of logical, integer, real, complex and tensor registers required in evaluating the compiled code.
instr is a list of actual compiled code instructions.
func is a Mathematica pure function to be used if no result can be obtained from the compiled code for any reason.
Compile generates a CompiledFunction object which can be executed by applying it to appropriate arguments.
CompiledFunction objects that are constructed explicitly can also be executed. Basic consistency checks are done when such objects are first evaluated by Mathematica.
The code in a CompiledFunction object is based on an idealized register machine.
See The Mathematica Book: Section 2.2.8 and Section 2.5.15.
See also: InterpolatingFunction.