PREPROCESSING IMPLIED SPECIFIERS IN A PIPELINED PROCESSOR

An instruction decoder (20) generates implied specifiers for certain predefined instructions, and an operand processing unit (21) preprocesses most of the implied specifiers in the same fashion as express operand specifiers. For instructions having an implied autoincrement or autodecrement of the stack pointer, an implied read or write access type is assigned to the instruction and the decode logic is configured accordingly. Conflicts created by the implied specifiers are handled in the same manner as conflicts for express specifiers. Moreover, by using the same data paths for both the implied specifiers and the express specifiers, and by inserting queues between the instruction unit and the execution unit, performance gains are realised for instructions having implied specifiers as well as just express specifiers.