US 7,568,087 B2
Partial load/store forward prediction
Sudarshan Kadambi, Sunnyvale, Calif. (US); Po-Yung Chang, Saratoga, Calif. (US); and Eric Hao, Cupertino, Calif. (US)
Assigned to Apple Inc., Cupertino, Calif. (US)
Filed on Mar. 25, 2008, as Appl. No. 12/55,016.
Application 12/055016 is a continuation of application No. 11/200744, filed on Aug. 10, 2005, granted, now 7,376,817.
Prior Publication US 2008/0177988 A1, Jul. 24, 2008
This patent is subject to a terminal disclaimer.
Int. Cl. G06F 7/38 (2006.01); G06F 9/00 (2006.01)
U.S. Cl. 712—225  [712/220] 29 Claims
OG exemplary drawing
 
1. A processor comprising:
a prediction circuit configured to predict whether or not a first load instruction will experience a partial store to load forward (PSTLF) event during execution, wherein a PSTLF event occurs for the first load instruction when a plurality of bytes that are to be written to a target of the first load instruction include at least a first byte updated responsive to a previous uncommitted store operation and also include at least a second byte not updated responsive to the previous uncommitted store operation; and
a circuit coupled to the prediction circuit and coupled to receive the first load instruction, wherein the circuit is configured to generate one or more load operations responsive to the first load instruction and further responsive to the prediction from the prediction circuit, wherein the load operations are to be independently executed in the processor to execute the first load instruction, and wherein each load operation accesses a different portion of the plurality of bytes, and wherein a first number of the load operations generated in response to the prediction indicating that the PSTLF event will occur is greater than a second number of the load operations generated in response to the prediction indicating that the PSTLF event will not occur, wherein the prediction circuit is further configured to provide a size indication, and wherein the first number of load operations is further responsive to the size indication.