Methods and apparatus to predict non-execution of conditional non-branching instructions

Abstract

Efficient techniques are described for not executing an issued conditional non-branch instruction. A conditional non-branch instruction is identified as being eligible for a prediction, the prediction indicating that the eligible conditional non-branch (ECNB) instruction would not execute. The ECNB instruction executes as a no operation (NOP) instruction in response to the prediction that the ECNB instruction would not execute. A source operand required for the ECNB instruction to execute is not fetched in response to the prediction to not execute.

Description

technical field [0001] The present invention relates generally to the field of processors, and in particular to processors supporting conditional non-branch instructions. Background technique [0002] Many portable products such as cell phones, laptop computers, personal data assistants (PDAs), etc. utilize processing systems that execute programs such as communication and multimedia programs. Processing systems for such products may include multiple processors, complex memory systems for storing instructions and data, controllers, peripherals such as communication interfaces, and fixed function logic blocks configured on, for example, a single chip. At the same time, portable products have limited energy sources in the form of batteries, which are often required to support high performance operations by processing systems. To increase battery life, these operations need to be performed as efficiently as possible. Many personal computers are also being developed with effic...

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Problems solved by technology

Additionally, conditional instructions may exist in software loops where the conditional resolution nature of the conditional instructions occurs in a similar fashion for each iteration of the loop, which can cause significant performance degradation

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