[Magic-dev] Re: Magic error message

[R. Timothy Edwards]

Dear Aswin Ramachandran,

> I work as a Teaching Assistant for Dr. James Stine at Oklahoma State 
> University.  We have a question regarding Magic and I'm sure you could 
> help us.
> 
> When I run magic with a filename as a parameter, we get the below 
> message (in red),
> 
> /x/cadence/lib/magic/sys/scmos.tech: line 6615: section drc:
>      OK types "space" in more than one plane.
>      Assuming same plane (active) as edge.
> 
> Though we could use the editor tools normally, we like to know if we 
> have to do something to fix this error message.

This error showed up when I rewrote some of the DRC parsing routines.
It turns out that pretty much all of the SCMOS set of techfiles has
one or two rules with an ambiguous use of "space".  Space appears
on all planes and therefore should be qualified with a plane (e.g.,
"space/a", "space/m1", etc.).  In the original syntax, there was only
one way to interpret the lines as written.  With my extended syntax,
it can be ambiguous, so I flag a warning message.  For example,
running magic on SCN4ME_SUBM.20.TSMC, I get the same error coming
from this line:

    edge4way poly,fp,rp,pc/a \
    ~(poly,fp,rp,pc/a,nfet,pfet,fet,hnfet,hpfet,hfet,prp)/active \
    1 space space 1 \
    "Poly spacing to Diffusion < 1 (Mosis #3.5)"

The use of "space" here means that ONLY space and no other material
type is allowed within 1 unit of poly where poly abuts field.  What's
ambiguous is that Magic can potentially check for material in any
plane, not just the plane of the edge.  The correct, unambiguous
rule should state "space/a" instead of "space".

This is not, in fact, an error, since Magic uses the most obvious
interpretation, which is correct in this case.

Hope that explanation helps!

					Regards,
					Tim

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