Arm Limited

David Gum Lim

Yasuo Ishii

Abhishek Raja

William Elton Burky

Muhammad Umar Farooq

Michael Brian Schinzler

Michael David Achenbach

Jason Lee Setter

A data processing apparatus is provided that comprises rename circuitry for performing a register rename stage of a pipeline in respect of a stream of operations. Move elimination circuitry performs a move elimination operation on the stream of operations in which a move operation is eliminated and the register rename stage performs an adjustment of an identity of registers in the stream of operations to compensate for the move operation being eliminated and demotion circuitry reverses or inhibits the adjustment in response to one or more conditions being met.

Move elimination

There is provided a data processing apparatus comprising decode circuitry responsive to receipt of a block of instructions to generate control signals indicative of each of the block of instructions, and to analyse the block of instructions to detect a potential hazard instruction. The data processing apparatus is provided with decode circuitry to encode information indicative of a clean restart point into the control signals associated with the potential hazard instruction. The data processing apparatus is provided with data processing circuity to perform out-of-order execution of at least some of the block of instructions, and control circuitry responsive to a determination, at execution of the potential hazard instruction, that data values used as operands for the potential hazard instruction have been modified by out-of-order execution of a subsequent instruction, to restart execution from the clean restart point and to flush held data values from the data processing circuitry.

Determining a restart point in out-of-order execution

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Austin, TX, United States of America

David Gum Lim