Patents Examined by Daivd Y. Eng
  • Patent number: 6289437
    Abstract: An out-of-order issue mechanism for a data processing system allows two out-of-order instructions to be issued to independent “pipes” from a window of four instructions currently queued for execution. If the two pipes execute floating pipe operations, dependencies between a computationally intensive floating point unit instruction (referred to as an fpu rr instruction) and the two previous computational intensive instructions having a target and a floating point register (the “fpr target”) are tracked to provide a mechanism that quickly determines when dependent data is available from one of the floating point unit pipes. The data is then used to preempt the issue of a dependent instruction until data is available. Additionally, this out-of-order issue mechanism recognizes when consecutive instructions are dependent upon a same operand.
    Type: Grant
    Filed: August 27, 1997
    Date of Patent: September 11, 2001
    Assignee: International Business Machines Corporation
    Inventors: Susan Elizabeth Eisen, James Edward Phillips