Not to be confused with micro-operation fusion.

Macro-Operation Fusion (Macro-Op Fusion or MOP Fusion) is a hardware optimization technique found in Intel's x86 microarchitectures whereby a pair of macro-operations are merged into a single macro-operation.

History

The technique for fusing instructions is owned by Intel under Patent US6675376 ("System and method for fusing instructions") originally filed in December 2000. MOP Fusion was first introduced in the Core microarchitecture and has been featured in every Intel microarch since.

Overview

After the boundaries of macro-ops are found and marked, they are delivered to the instruction queue. At that stage of the pipeline, macro-operation fusion opportunities can be identified and exploited.