Re: [Iverilog-devel] $time et al. in continuous assignments

[Cary R. <cy...@ya...>]

--- On Sun, 12/14/08, Martin Whitaker <mai...@ma...> wrote:

> Aren't you going to have to write code to check that a
> function meets the conditions that allow it to be replaced
> by a constant? Or were you intending to do this on the fly
> as you evaluated the function.

I already have checks to verify that the arguments are
constant and yes I'm planning to do the rest on the fly
in the eval_tree infrastructure. If I run into something
that isn't allowed I just return 0 and everything unwinds
into a normal function call. It would be nice to know if
the function was being evaluated in a constant context vs
a compiler optimization. The later is allowed to become a
normal function call, but the former should really give an
error vs a zero result. Actually this will give an error
message, but it is only that the function did not evaluate
to a constant value instead of exactly why the function
could not be evaluated as a constant. I plan to keep all
this in mind as I'm working on things, but may add this
after I get constant functions fully implemented. In
reality all of the eval_tree functions could benefit
from the constant context information.

> > I really need to get myself a copy of 1364-2005!
...
> I found it was cheaper to buy online from ANSI
> (www.ansi.org) than from the IEEE. It may be different if
> you're an IEEE member.

Thanks, I will check both since I have easy access to
multiple IEEE members.

Cary