Early issue of null-predicated operations

摘要

In an embodiment, a processor includes an issue circuit configured to issue instruction operations for execution. The issue circuit may be configured to monitor the source operands of the instruction operations, and to issue instruction operations for which the source operands (including predicate operands, as appropriate) are resolved. Additionally, the issue circuit may be configured to detect a null predicate that indicates that none of the vector elements will be modified by a corresponding instruction operation. The issue circuit may be configured to issue the corresponding instruction operation with the null predicate even if other source operands are not yet resolved.

主权项

1. A processor comprising:
an issue circuit configured to issue instruction operations for execution in the processor, wherein a first instruction operation in the issue circuit has a plurality of source operands including at least one predicate from a first predicate register and one or more vectors from one or more vector registers, and wherein the issue circuit is configured to issue the first instruction operation responsive to the at least one predicate being a null predicate and wherein the issue circuit is configured to issue the first instruction operation even in the case that at least one of the dependencies on the one or more vectors is unresolved when the first instruction operation is issued; and a vector execution unit coupled to the issue circuit and configured to execute the first instruction operation independent of the one or more vectors having the unresolved dependencies, and further configured to forward a result of the first instruction operation to a dependent instruction operation in the issue circuit independent of the one or more vectors having the unresolved dependencies and prior to at least one of the unresolved dependencies being resolved.