1METHOD TO PREVENT PIPELINE STALLS IN SUPERSCALAR STACK BASED COMPUTING SYSTEMS

An execution unit for a stack based computing system that can combine instructions into instruction groups for concurrent execution is provided. In accordance with one embodiment, the instructions of the stack based computing system are separated into different instruction types. Certain combinations of instruction types can be combined into instruction groups for concurrent execution. The execution unit includes an instruction folding unit that is configured to determine the instruction type of instructions and combine the instructions into instruction groups, and an instruction pipeline that is configured to process both instructions and instruction groups. In one embodiment, the instruction folding unit includes: an instruction type estimator which estimates the instruction types of various instructions; an instruction selector, which selects the instruction types from the estimated instruction types; and a folding logic circuit which combines the instructions into instruction groups.