A system for adding advanced instructions to a microprocessor includes a language for formally capturing the new instructions and a method for generating hardware implementations and software tools for the extended processors. The extension language provides for additions of VLIW instructions, complex load/store instructions, more powerful description styles using functions, more powerful register operands, and a new set of built-in modules. The method is capable of generating fully-pipelined micro-architectural implementations for the new instructions in the form of synthesizable HDL descriptions which can be processed by standard CAD tools. The method is also capable of generating software components for extending software development tools for the microprocessor with new instructions.