Re: [Iverilog-devel] Numeric attributes

[Martin W. <ic...@ma...>]

Indeed, the standard allows an attribute value to be any constant 
expression. So real values would be allowed too. But nobody has complained 
that they aren't accepted, so I guess they aren't widely used.

Stephen Williams wrote:
> Recently I noticed that there may be a problem with numeric attributes
> at the ivl_target.h API. Specifically, the API is converting numeric
> attributes to host integers. This winds up truncating values to 64
> (63) bits, and drops x and z bit values. My reading of the standard is
> that numeric attributes have no such limitations, so it appears that
> the API is wrong.
> 
> So, my questions are:
> 
> 1) Anybody out there using attributes? They are accessible at the
> ivl_target.h API level, so if you are writing code generators, you
> might be using attributes. I don't think they are available through
> PLI.
> 
> 2) Anybody have an opinion on whether numeric attributes are treated
> as 4-value logic in other tools? Or am I fooling myself and numeric
> attributes really do evaluate down to host integers?
> 
> 3) What do other tools do?
> 
>