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Altera_Forum's avatar
Altera_Forum
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22 years ago

Register view

I noticed that while stepping thru some assembly, I could not alter the outcome of a cmpge if I changed one of the register values just before the compare. I thought I would be able to do this, particularly on an e core. This brings up the question of how the debug interface is tied into the different processor cores. How is normal execution altered (pipeline, etc) while stepping?

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  • Altera_Forum's avatar
    Altera_Forum
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    Now I see. You have to use sign extended values for these compares.

    The question about pipeline is still valid. Does running under the debugger basically disable any pipeline?
  • Altera_Forum's avatar
    Altera_Forum
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    When you are single-stepping it appears as though the pipeline is disabled.

    In the Nios II/s and Nios II/f, multiple instructions are dispatched into the pipeline

    when single stepping but only the first is allowed to complete. The other instructions

    are flushed before modifying any programmer-visible state.

    The Nios II/e doesn't really have a pipeline so it is in a sense always single stepping.