A system for adding reconfigurable computational instructions to a computer, the system comprising a processor operable to execute a set of instructions of a computer program comprising a set of computational instructions and long instruction word instructions with at least one of the long instruction word instructions comprising an instruction extension, an extension adapter coupled to the processor and operable to detect the execution of the instruction extension, and programmable logic coupled to the extension adapter and operable to receive configuration data for defining the instruction extension and execute the instruction extension.