公开(公告)号：MY125518A

公开(公告)日：2006-08-30

申请号：MYPI20003468

申请日：2000-07-28

Applicant: IBM

Inventor： GSCHWIND MICHAEL K ,  SATHAYE SUMEDH

IPC: G06F9/00 ,  G06F9/30 ,  G06F9/32 ,  G06F9/38

Abstract: THERE IS PROVIDED A METHOD FOR EXECUTING AN ORDERED SEQUENCE OF INSTRUCTIONS IN A COMPUTER PROCESSING SYSTEM (300).THE SEQUENCE OF INSTRUCTIONS IS STORED IN A MEMORY (305) OF THE SYSTEM. AT LEAST ONE OF THE INSTRUCTIONS INCLUDES A PREDICATED INSTRUCTION THAT REPRESENTS AT LEAST ONE OPERATION THAT IS TO BE CONDITIONALLY PERFORMED BASED UPON AN ASSOCIATED FLAG VALUE. THE METHOD INCLUDES THE STEP OF FETCHING A GROUP OF INSTRUCTIONS FROM THE MEMORY. EXECUTION OF INSTRUCTIONS ARE SCHEDULED WITHIN THE GROUP, WHEREIN THE PREDICATED INSTRUCTION IS MOVED FROM ITS ORIGINAL POSITION IN THE ORDERED SEQUENCE OF INSTRUCTIONS TO AN OUT-OF-ORDER POSITION IN THE SEQUENCE OF INSTRUCTIONS. THE INSTRUCTIONS ARE EXECUTED IN RESPONSE TO THE SCHEDULING. IN ONE EMBODIMENT OF THE INVENTION, THE METHOD FURTHER INCLUDES GENERATING A PREDICTED VALUE FOR THE ASSOCIATED FLAG VALUE, WHEN THE ASSOCIATED FLAG VALUE IS NOT AVAILBALE AT EXECUTION OF THE PREDICATED INSTRUCTION. IN ANOTHER EMBODIMENT, THE METHOD FURTHER INCLUDES MODIFYING EXCUTION OF THE OPERATIONS REPRESENTED BY THE PREDICATED INSTRUCTION BASED UPON THE PREDICTED VALUE. IN YET ANOTHER EMBODIMENT, THE MODIFYING STEP INCLUDES SELECTIVELY SUPPRESSING EITHER THE EXECUTION OR WRITE BACK OF RESULTS GENERATED BY THE OPERATIONS REPRESENTED BY THE PREDICATED INSTRUCTION BASED UPON THE PREDICTED VALUE. IN STILL ANOTHER EMBODIMENT, THE METHOD INCLUDES PREDICATING A DATA DEPENDENCE RELATIONSHIP OF AN INSTRUCTION WITH A PREVIOUS PREDICATED INSTRUCTION OR ANOTHER PREVIOUS INSTRUCTION. THE CORRECTNESS OF THE RELATIONSHIP PREDICTION MAY BE VERYFIED, AND A SELECTION MAY BE MADE FROM AMONG A NUMBER OF PREDICTED DEPENDENCES. (FIG. 3)