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Old 05-21-2009, 01:09 PM
Brian Drummond
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Default Re: ISIM and CONV_INTEGER warnings

On Wed, 20 May 2009 10:32:06 +0100, "HT-Lab" <[email protected]> wrote:

>Does anybody know how to disable the CONV_INTEGER warnings in ISIM (11.1)?
>
>at 3000290500 ps(1), Instance /cpu_top_tb/U_12/ : Warning: CONV_INTEGER:
>There is an 'U'|'X'|'W'|'Z'|'-' in an arithmetic operand, and it has been
>converted to 0.
>at 3000365500 ps(1), Instance /cpu_top_tb/U_12/ : Warning: CONV_INTEGER:
>There is an 'U'|'X'|'W'|'Z'|'-' in an arithmetic operand, and it has been
>converted to 0.


I don't see these errors from CONV_INTEGER because I use numeric_std instead,
but it looks like the same situation.

My response is to identify the worst culprits and apply "to_01" functions in
appropriate places. I usually live with the remainder which in my projects are
confined to the first few hundred ns after reset as valid signals propagate
through the pipelines.

This way (a) I don't have to globally suppress the warning, so unexpected
consequences of later changes can be caught as early as possible.
(b) I am aware of where the "problem" is occurring and happy that it is only the
result of expected (and allowed) circumstances as above.

It sounds like a tedious task but you may be surprised by how few "to_01"
functions are required; probably half a dozen on the designs I have experience
of.

- Brian
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