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From: simpson@trwrb.UUCP (Scott Simpson)
Newsgroups: comp.laser-printers
Subject: Porting METAFONT to the Pyramid
Message-ID: <8708070029.AA08497@brillig.umd.edu>
Date: Wed, 5-Aug-87 22:57:50 EDT
Article-I.D.: brillig.8708070029.AA08497
Posted: Wed Aug  5 22:57:50 1987
Date-Received: Sun, 9-Aug-87 08:33:55 EDT
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Approved: laser-lovers@brillig.umd.edu

A couple of weeks ago I requested a change file for METAFONT that would compile
under the OSx 4.0 Pascal compiler. (The old OSx 3.5 change file did not work).
I expect that many of you Pyramid sites have not upgraded to 4.0 OSx since I
did not receive any offers of a change file.  Consequently, I decided to get my
fingers dirty and fix the METAFONT change file myself.
	It seems that with this new release of the operating system, Pyramid
has made their compiler compatible with the ISO standard and packed array
elements can no longer be passed by reference.  This causes a compilation error
when str_pool is passed to the C calledit routine in TeX and METAFONT.  Since
the Pyramid pascal compiler packs character arrays anyway, you can simply
remove the packed keyword from the str_pool declaration in TeX and METAFONT.
This will enable both to compile and TeX will work fine but inimf will go
into an infinite loop when it tries to read in the plain.mf file.
	METAFONT needs a couple of more changes.  With the new pascal compiler,
you must declare eight bit bytes as 0..255 instead of -128..127 and you must
declare 16 bit half words as 0..65536 instead of -32768..32767.  Consequently,
you will need to set the following constants appropriately in the inimf change
file:
	mem_max=30000
	mem_min=0
	mem_top=30000
	min_quarterword=0
	max_quarterword=255
	min_halfword=0
	max_halfword=65536
Just change the values that are already there.  Inimf will now compile
correctly.  For virmf, I changed the value mem_max to 60000 in the ini_to_vir
script.
	Dvitype breaks too.  There is a bug in the pascal compiler that causes
expressions to sometimes be evaluated incorrectly.  (I reported it to Pyramid.)
In the routine signed_quad, the expression

	signed_quad := (((ord(a) - 256) * 256 + ord(b)) * 256 + ord(c)) * 256 
	+ ord(d);

does not evaluate correctly.  If you declare "i" and change this to

	begin
	    i := ((ord(a) - 256) * 256 + ord(b)) * 256 + ord(c);
	    signed_quad := i * 256 + ord(d);
	end;

dvitype works correctly.  Good luck!
		Scott Simpson
		TRW Space and Defense Sector
		...{decvax,ihnp4,ucbvax}!trwrb!simpson