Specifies the ports (pinstubs) of a primitive, megafunction, or macrofunction in AHDL. A Function Prototype consists of the name of the function, and a list of its inputs and outputs. For mega- and macrofunctions, the Function Prototype can also contain parameters that are used to specify the characteristics of the function. Function Prototypes are specified in the Function Prototype Statement. They are often stored in AHDL Include Files (.inc). INC Files that contain Function Prototypes for Altera-provided megafunctions are located in the \quartus\libraries\megafunctions directory created during installation.

To implement an instance of a mega- or macrofunction in AHDL, you must define its logic in a design file and declare its Function Prototype. (Function Prototypes are optional for primitives.) You can then create an instance of the function with an Instance Declaration or an in-line logic function reference.

When you use a Module Instantiation in Verilog HDL, the Compiler uses the port name and order information in INC Files that contain Function Prototypes to implement an instance of the logic function.

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