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mismatching instruction cycles between the simulator and manual

jay kim

Hi,

While evaluating the efficiency of Cortex-M4, I found that simulator's cycle counts for several instructions are inconsistent with the manual.
For example, the simulator counts 3 cycles for SMULL, while it is denoted as 1 in the Cortex-M4 technical reference manual (doc number DDI0439C, table3-1).

please someone tell me which one is correct??

I am using MDK-ARM 4.60 eval. with 'generic Cortex-M4' setting.

Thanks and regards,
jay

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  • 0

    The simulator is just an approximation.

    And the simulation of Cortex-Mx chips are just extensions of simulations of other ARM chips in Thumb mode. So the simulator is likely to be wrong now and then.

    Do you have any reasons to not trust ARM:s documentation of their own processor cores?

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  • 0

    The simulator is just an approximation.

    And the simulation of Cortex-Mx chips are just extensions of simulations of other ARM chips in Thumb mode. So the simulator is likely to be wrong now and then.

    Do you have any reasons to not trust ARM:s documentation of their own processor cores?

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