Digital Equipment Corporation

Cheryl A Wiecek

Tryggve Fossum

Francis X McKeen

Dileep P Bhandarkar

A method for translating an initial program flow representation of a computer program into a modified program flow representation examines paths in the initial program flow representation, selects for replication nodes which have multiple predecessor nodes and a single successor node which have never been path search exit nodes and which are neither loop members of successors of loop members. Some of those selected nodes are then replicated and replace the nodes that were replicated. The program flow representation can then be reduced by combining nodes which have a predetermined relationship. This resulting flow representation is well suited for translation into a desired computer language.

Methods and apparatus for transforming machine language program control

A data processing system handles memory management exceptions caused by a faulting vector instruction in a vector processor by halting the execution of the faulting vector instruction being executed when the exception occurred and by setting the state information for the vector processor to acknowledge the presence of the exception and to include information about the suboperation of the vector instruction being executed when the exception occurred. The scalar processor is not interrupted at this time, however. Any other vector instructions executing simutaneously with the faulting vector instruction are allowed to continue so long as those instructions do not require data from the faulting instruction. The faulting partially completed vector instruction resumes execution after the operating system has processed the memory management exception.

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Westford, MA, United States of America

Cheryl A Wiecek