[Magic-dev] Starting magic with custom tech file

[R. Timothy Edwards]

Dear Graham,

>    I want to start magic with my own tech file called pharosc.tech. If this is
> in the working directory or in $CAD_ROOT/magic/sys, then I can start magic like
> 
> $ magic -Tpharosc
> 
> But I want to put the file in ~/magic/etc. I tried editing the .magicrc file to
> define the path, but this is read *after* the -T on the command line, so magic
> fails to find pharosc.tech and uses scmos.tech instead (without saying it has
> ignored the -Tpharosc).
> 
>    I added a tech file load after the path in .magicrc:
> 
> path sys ". /home/graham/magic/etc /home/cad/lib/magic/sys"
> tech load pharosc.tech -noprompt
> 
> Now I can start magic
> 
> $ magic
> 
> and it loads my tech file, but after scmos.tech which causes a red warning
> message in the tkcon window

> Warning:  Number of planes has changed.  Any existing layout may be invalid.
> 
>    And I also don't get the version message from my tech file which I would
> like to see.

I can't say that I have thought much about this since I coded the part
that allows you to reload the techfile from the .magicrc file, which
you did correctly.  Basically I've just gotten used to it always generating
one red warning message.

However, there are two things I can do here:  1) Print out the version
information upon "tech load" (which seems sensible enough and simple enough
to implement), and 2) Check for actual layout before printing the abovementioned
warning message.  The "any existing layout may be invalid" is a true statement
to be taken at face value, but it should not be very difficult for magic to
make a quick check that (a) only the default top-level cell has been loaded,
and (b) all planes in the default cell contain only "space" tiles.  If it
passes that check, then it should not print the warning message.

Otherwise, what you have done is exactly correct.  You should be able run
"magic -T /home/graham/magic/etc/pharosc" from the command line (if that
doesn't work, let me know).  I prefer loading the correct techfile from
the .magicrc file, so I create a .magicrc file for each project.

					Regards,
					Tim

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| Dr. R. Timothy Edwards (Tim)   | email: tim at opencircuitdesign.com    |
| Open Circuit Design, Inc.	 | web:   http://opencircuitdesign.com |
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