1. A processing system with reconfigurable instruction extensions, the system comprising: a processor operable to execute a computer program comprising a set of computational instructions and at least one instruction extension; programmable logic operable to receive configuration information to configure the programmable logic for the instruction extension and operable to execute the instruction extension; an extension adapter coupled to the processor, the extension adapter operable to: detect an instruction extension issued by the processor, detect a residency of the issued instruction extension in the programmable logic, and communicate an exception to the processor based on residency of the issued instruction extension in the programmable logic; the processor operable to issue a fault to the operating system in response to the exception; a register file coupled to the programmable logic and operable to store data; and a load/store module operable to transfer the data directly between the register file and a system memory.