Re: [Iverilog-devel] How to get more information when internal errors happen

[Stephen W. <st...@ic...>]

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Larry Doolittle wrote:
> This particular bug looks like it's in the vvp code generator.
> It prints out
> 
> L_0x81cde48 .concat [ 4 2 0 0], C4<0000>, L_0x81cdef0;
> 
> but the second width (2) should really be 0.
> The code that prints the erroneous 2 is in tgt-vvp/vvp_scope.c:1828,
> function lpm_concat_inputs().  I didn't trace back width_of_nexus()
> yet to see where the bug really is.  The elaborated design itself
> looks correct.

The elaboration is probably *not* correct if L_0x81cdef0 is
thought to be width of zero. It looks like the concat writer
thinks it should be width of 2.

At this point, the -tstub target may be the needed magic. That
code generator doubles as a compiler sanity checker and may detect
the bad situation here. Just run iverilog -v -Wall -tstub test_tb.v
and see if the resulting a.out has ERROR strings in it anywhere.

- --
Steve Williams                "The woods are lovely, dark and deep.
steve at icarus.com           But I have promises to keep,
http://www.icarus.com         and lines to code before I sleep,
http://www.picturel.com       And lines to code before I sleep."
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