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From: morgan@ms.uky.edu (Wes Morgan)
Newsgroups: comp.lang.fortran
Subject: Strange EQUIVALENCES and data inits
Keywords: VAX FORTRAN --> UNIX F77
Message-ID: <14121@s.ms.uky.edu>
Date: 12 Feb 90 20:02:49 GMT
Organization: U of Ky, Math. Sciences, Lexington KY
Lines: 45


I am attempting to port the PD MATLAB package to a 3B20 with f77.
The following chunk of code refuses to compile:

      DOUBLE PRECISION MASK(14),XX,MM
      real mas(2,14)
      equivalence (mask(1),mas(1))
      data mas/
     $ z'ffffffff',z'fff0ffff',
     $ z'ffffffff',z'ff00ffff',
     $ z'ffffffff',z'f000ffff',
     $ z'ffffffff',z'0000ffff',
     $ z'ffffffff',z'0000fff0',
     $ z'ffffffff',z'0000ff00',
     $ z'ffffffff',z'0000f000',
     $ z'ffffffff',z'00000000',
     $ z'fff0ffff',z'00000000',
     $ z'ff00ffff',z'00000000',
     $ z'f000ffff',z'00000000',
     $ z'0000ffff',z'00000000',
     $ z'0000fff0',z'00000000',
     $ z'0000ff80',z'00000000'/

My errors have been "initializing noncharacter datum with a character
string" and "invalid types in initialization".

It would appear that the original author is trying to force bit patterns
into a real array.  My first attempt was to change the equivalence args
to (mask(1),mas(1,1)); that crashed and burned.  My second thought was 
to redefine mas as character*32, rather than real. That, too, bit the
dirt.

Could some fortran wizard out there kindly fill me in on
   a) What the author is *really* attempting to do here, and
   b) How to make the f77 compiler swallow this mess? 

Many thanks,
Wes Morgan


-- 
  The opinions expressed above are not those of UKECC unless so noted.
Wes Morgan                 \       {rutgers,rayssd,uunet}!ukma!ukecc!morgan
University of Kentucky      \   or morgan@engr.uky.edu
Engineering Computing Center \  or morgan%engr.uky.edu@UKMA.BITNET