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From: herndon@umn-cs.UUCP
Newsgroups: comp.lang.c
Subject: Re: Long Branches
Message-ID: <53900002@umn-cs.UUCP>
Date: Thu, 22-Jan-87 17:30:00 EST
Article-I.D.: umn-cs.53900002
Posted: Thu Jan 22 17:30:00 1987
Date-Received: Sat, 24-Jan-87 08:38:08 EST
References: <3950006@nucsrl.UUCP>
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Nf-ID: #R:nucsrl:-395000600:umn-cs:53900002:000:1059
Nf-From: umn-cs!herndon    Jan 22 16:30:00 1987



  The code in question appears to the York Prolog interpreter.
I had exactly the same problem with the interpreter and found
that turning on the optimizer fixed the problem.  I did not
actually examine the assembler code produced.  I often ran
into strange problems with the BSD 4.2 C compiler and didn't
really have time to putz around trying to fix the compiler.
  As I recall, the York interpreter itself had some problems.
Variable lookup was very slow (linear search; not even a hashing
scheme) and the initialization time was long (that I fixed by
'checkpointing' the interpreter after initialization and
constructing an executable binary image of the initialized
interpreter).  The code appeared to be otherwise well written
in strict ISO pascal.
  We later got Cprolog -- York is now (virtually) unused.
It is much faster, has better debugging features, ...

				Robert Herndon
				...!ihnp4!umn-cs!herndon
				herndon@umn-cs.ARPA
				Dept. of Computer Science,
				Univ. of Minnesota,
				136 Lind Hall, 207 Church St. SE
				Minneapolis, MN  55455