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- Output of lpm_divide is x's when inputs are 0 in modelsim

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Altera_Forum

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01-24-2013
10:23 PM

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Output of lpm_divide is x's when inputs are 0 in modelsim

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Altera_Forum

Honored Contributor I

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01-25-2013
06:46 AM

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Although zero divide by zero is mathematically NAN (not-a-number), a parallel divider should give a defined '0'/'1' bit vector.

I don't see a reason to expect an all '0' output. The MegaFunction user manual specifies 'x' output for divide by zero. I think, this means it's up to the synthesis tool optimization to make individual bit either '0' or '1'. The simulator is apparently reflecting this ambiguity, you should run a gate level simulation to see the actual output. Forcing zero output for divide by zero requires additional logic anyway.
Altera_Forum

Honored Contributor I

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01-25-2013
05:25 PM

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For more complete information about compiler optimizations, see our Optimization Notice.