Abstract: In a computer system, a method and apparatus for dispatching and executing multi-cycle and complex instructions. The method results in maximum performance for such without impacting other areas in the processor such as decode, grouping or dispatch units. This invention allows multi-cycle and complex instructions to be dispatched to one port but executed in multiple execution pipes without cracking the instruction and without limiting it to a single execution pipe. Some control signals are generated in the dispatch unit and dispatched with the instruction to the Fixed Point Unit (FXU). The FXU logic then execute these instructions on the available FXU pipes. This method results in optimum performance with little or no other complications. The presented technique places the flexibility of how these instructions will be executed in the FXU, where the actual execution takes place, instead of in the instruction decode or dispatch units or cracking by the compiler.
Type:
Grant
Filed:
May 12, 2003
Date of Patent:
August 1, 2006
Assignee:
International Business Machines Corporation
Inventors:
Fadi Y. Busaba, Steven R. Carlough, Christopher A. Krygowski, John G. Rell, Jr., Timothy J. Slegel