公开(公告)号：US20240354109A1

公开(公告)日：2024-10-24

申请号：US18305151

申请日：2023-04-21

Applicant: Apple Inc.

Inventor： Yuan C. Chou ,  Deepankar Duggal ,  Debasish Chandra ,  Niket K. Choudhary ,  Richard F. Russo

IPC: G06F9/38 ,  G06F9/30

CPC classification number: G06F9/3802 ,  G06F9/30043 ,  G06F9/3016 ,  G06F9/3861

Abstract: Disclosed techniques relate to re-use of speculative results from an incorrect execution path. In some embodiments, when a control transfer instruction is mispredicted, a load instruction may have been executed on the wrong path. In disclosed embodiments, result storage circuitry records information that indicates destination registers of speculatively-executed load instructions including a first load instruction. Control flow tracker circuitry may store information indicating a reconvergence point for the control transfer instruction. Re-use control circuitry may track registers written by instructions prior to the reconvergence point, determine that the first load instruction does not depend on data from any instruction between the control transfer instruction and the reconvergence point, and use, as a result of the first load instruction, a value from a recorded destination register that was written based on speculative execution of the first load, notwithstanding the misprediction of the control transfer instruction.

公开(公告)号：US12045615B1

公开(公告)日：2024-07-23

申请号：US17933040

申请日：2022-09-16

Applicant: Apple Inc.

Inventor： Deepankar Duggal ,  Kulin N Kothari ,  Mridul Agarwal ,  Chang Xu ,  Yanran Yang ,  Richard F Russo ,  Yuan C Chou ,  Douglas C Holman

IPC: G06F9/30 ,  G06F9/38 ,  G06F9/52

CPC classification number: G06F9/30087 ,  G06F9/3802 ,  G06F9/522

Abstract: A system, e.g., a system on a chip (SOC), may include one or more processors. A processor may execute an instruction synchronization barrier (ISB) instruction to enforce an ordering constraint on instructions. To execute the ISB instruction, the processor may determine whether contexts of the processor required for execution of instructions older than the ISB instruction are consumed for the older instructions. Responsive to determining that the contexts are consumed for the older instructions, the processor may initiate fetching of an instruction younger than the ISB instruction, without waiting for the older instructions to retire.

公开(公告)号：US11416254B2

公开(公告)日：2022-08-16

申请号：US16705023

申请日：2019-12-05

Applicant: Apple Inc.

Inventor： Deepankar Duggal ,  Kulin N. Kothari ,  Conrado Blasco ,  Muawya M. Al-Otoom

IPC: G06F9/30 ,  G06F9/38

Abstract: Systems, apparatuses, and methods for implementing zero cycle load bypass operations are described. A system includes a processor with at least a decode unit, control logic, mapper, and free list. When a load operation is detected, the control logic determines if the load operation qualifies to be converted to a zero cycle load bypass operation. Conditions for qualifying include the load operation being in the same decode group as an older store operation to the same address. Qualifying load operations are converted to zero cycle load bypass operations. A lookup of the free list is prevented for a zero cycle load bypass operation and a destination operand of the load is renamed with a same physical register identifier used for a source operand of the store. Also, the data of the store is bypassed to the load.

公开(公告)号：US09952863B1

公开(公告)日：2018-04-24

申请号：US14842421

申请日：2015-09-01

Applicant: Apple Inc.

Inventor： Conrado Blasco ,  Deepankar Duggal ,  Richard F. Russo

IPC: G06F9/44 ,  G06F9/45 ,  G06F9/445 ,  G06F9/30 ,  G06F9/38 ,  G06F9/32

CPC classification number: G06F9/3005 ,  G06F9/30079 ,  G06F9/30145 ,  G06F9/327 ,  G06F9/3855 ,  G06F11/30

Abstract: Techniques are disclosed relating to capturing information related to instructions executing on in a processor. In one embodiment, an integrated circuit is disclosed that includes an execution pipeline configured to execute a sequence of instructions. The integrated circuit includes monitoring circuitry configured to monitor the execution pipeline for occurrences of an event associated with the sequence of instructions, and in response to detecting a particular number of occurrences of the event, capture a value of a program counter corresponding to an instruction of the sequence of instructions that is associated with an occurrence of the event. The monitoring circuitry stores the captured value of the program counter in a distinct capture register and signals an interrupt indicating that the captured value of the program counter is retrievable from the capture register. In some embodiments, a debugging application may retrieve the value and present it to a developer attempting perform code profiling.