g77 problem

[Kevin Maguire]

Hi

I am using

% g77 -v
Reading specs from /usr/local/egcs/lib/gcc-lib/i686-pc-linux-gnu/egcs-2.90.29/specs
gcc version egcs-2.90.29 980515 (egcs-1.0.3 release)

I have a F77 code which is giving me problems.  I have tracked it down
to this section:

....
       SCTT=DEXP(-SCT1)
       SCT3=DEXP(-SCT1)
       print "(3F20.10)",SCT1,SCTT,SCT3
       STOP

which is producing

        1.9546141298                 NaN        0.1416191127

i.e. DEXP is returning NaN the first time it is called, with a valid
argument?  Is this a known problem, if it is is there a fix.  Might
this be a problem somewhere else in the code, if so how can I
diagnose the problem.

I tried to reduce the problem to a smaller size (the code is about 40k
lines of F77), but so far I have been unable to get a shorter test
progam to fail!!

Cheers
Kev
-- 
   /\___/\    ==============================================
   | o o |    Kevin Maguire          Computational Scientist
  __\_^_/__   DCI                  CLRC Daresbury Laboratory
 (__/   \__)  e-mail:                     K.Maguire@dl.ac.uk
  _|  :  |_   Tel: 01925 603221            Fax: 01925 603634
 (__\___/__)  ==============================================