公开(公告)号：GB2322718A

公开(公告)日：1998-09-02

申请号：GB9725995

申请日：1997-12-09

Applicant: IBM

Inventor： HICKS TROY NEAL ,  LE HUNG OUI ,  MUHICH JOHN STEPHEN ,  WHITE STEVEN WAYNE

IPC: G06F9/38

Abstract: A pre-execution queue PEQ 42 stores instructions for an information handling system, and schedules the issuing of these instructions to at least one execution cluster 54, 56, each comprising an early, 46, 50, and a late, 48, 52, execution unit. Each execution unit executes an instruction dispatched from PEQ 42, and generates and forwards a result to another unit for execution of a further instruction. This result data forwarding takes longer if it is between units of different clusters. In particular, a result from early unit 46 is available to late unit 48 in the same cluster 54 in the same clock cycle. The instruction scheduling takes into account this non-uniform forwarding of result data (for example, by "pairing" dependent instructions and issuing them to the same cluster), and ensures that only instructions whose operands are available are scheduled. PEQ 42 classifies and groups the instructions into buckets with associated selection priorities (fig. 6). Instructions can be dynamically reassigned to buckets in response to execution delays and priority conflicts.