US 12,093,692 B2
Apparatus and method with prediction for load operation
. Abhishek Raja, Niagara Falls, NY (US)
Assigned to Arm Limited, Cambridge (GB)
Filed by Arm Limited, Cambridge (GB)
Filed on Feb. 14, 2023, as Appl. No. 18/109,297.
Application 18/109,297 is a continuation in part of application No. 17/670,762, filed on Feb. 14, 2022, granted, now 11,948,013.
Application 17/670,762 is a continuation in part of application No. 17/208,130, filed on Mar. 22, 2021, granted, now 11,513,966, issued on Nov. 29, 2022.
Prior Publication US 2023/0185573 A1, Jun. 15, 2023
Int. Cl. G06F 9/38 (2018.01); G06F 9/30 (2018.01)
CPC G06F 9/3806 (2013.01) [G06F 9/30043 (2013.01); G06F 9/3842 (2013.01)] 19 Claims
OG exemplary drawing
 
1. An apparatus comprising:
processing circuitry to issue load operations to load data from a data store;
load tracking circuitry to maintain tracking information for one or more load operations issued by the processing circuitry; and
load prediction circuitry to determine a prediction for enabling a load operation to be speculatively issued ahead of an older load operation based on the prediction before it is known whether the prediction is correct; in which:
the load tracking circuitry is configured to:
determine whether the tracking information indicates that there is a risk of target data, corresponding to an address of a speculatively-issued load operation which is speculatively issued based on the prediction determined by the load prediction circuitry, having changed between the target data being loaded for the speculatively-issued load operation and data being loaded for a given older load operation bypassed by the speculatively-issued load operation; and
in response to determining that the tracking information indicates that that there is a risk of the target data having changed between the target data being loaded for the speculatively-issued load operation and data being loaded for the given older load operation, and independent of whether the address of the speculatively-issued load operation corresponds to an address of the given older load operation, request re-issuing of at least the speculatively-issued load operation, even when the prediction for the speculatively-issued load operation is correct.