Computer Dictionary of Information Technology

Very Long Instruction Word

(VLIW) Used to describe a machine code instruction set implemented using horizontal microcode. A horizontally encoded instruction word which encodes four or more operations might be considered "very long".

VLIW architectures are sometimes classified as a type of static superscalar architecture. They are static in the sense that which units operate in parallel is determined by the instruction rather than by dynamic scheduling at run time.

Producing code for VLIW machines is difficult; trace scheduling is a helpful compiler technique.

The most famous VLIW machine was built by (the late) Multiflow Computer, Inc.