DOCUMENT:Q100377  24-MAR-2000  [fortran]
TITLE   :FIX: F1001: confold.c Line 253, Negative Integer Exponent
PRODUCT :Microsoft Fortran Compiler
PROD/VER::1.0,1.0a
OPER/SYS:
KEYWORDS:kberrmsg kbCompiler kbFL32 kbFortranPS

======================================================================
-------------------------------------------------------------------------------
The information in this article applies to:

 - Microsoft FORTRAN PowerStation for MS-DOS, versions 1.0, 1.0a 
 - Microsoft Fortran Powerstation 32 for Windows NT, version 1.0 
-------------------------------------------------------------------------------

SYMPTOMS
========

An attempt to compile an application fails and Microsoft FORTRAN PowerStation
version 1.0 for MS-DOS displays the following message:

   fatal error F1001: INTERNAL COMPILER ERROR
   (compiler file '@(#)confold.c:1.144', line 253)
   Contact Microsoft Product Support Services

FORTRAN PowerStation version 1.0a for MS-DOS displays the following error
message:

   fatal error F1001: INTERNAL COMPILER ERROR
   (compiler file '@(#)confold.c:1.144', line 254)
   Contact Microsoft Product Support Services

CAUSE
=====

The command line specifies the /Ox optimization and the code contains an
expression that computes a negative integer power of a constant integer or of an
integer expression. The error above occurs when the compiler processes the unary
minus operator in an integer exponentiation expression.

RESOLUTION
==========

There are two methods to work around this problem:

 - Modify the compiler command line to specify the /Oxp compiler option switch.

 - Modify the source code to remove the unary minus operator from integer
   expressions used as exponents. Assign the exponent to a temporary variable
   and negate the value. Then specify the temporary as the exponent.

STATUS
======

Microsoft has confirmed this to be a problem in the Microsoft products listed at
the beginning of this article. This problem was fixed in FORTRAN PowerStation
32, version 4.0.

MORE INFORMATION
================

The following sample code demonstrates this problem:

Sample Code #1
--------------

   c Compiler options needed: /Ox

         program test
         integer j
         real    x

         j = 1
         x = 2**(-j)
         print *, x
         end

The following sample code demonstrates one method to work around this problem:

Sample Code #2
--------------

   c Compile options needed: /Ox

         program test
         integer j
         real    x

         j = 1
         j = -j      ! Negation occurs here.
         x = 2**(j)
         print *, x
         end

Additional query words: 1.00 1.00a

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Keywords          : kberrmsg kbCompiler kbFL32 kbFortranPS 
Technology        : kbAudDeveloper kbFortranSearch kbZNotKeyword2 kbZNotKeyword3 kbFORTRANPower32100NT kbFORTRANPower100DOS kbFORTRANPower100aDOS
Version           : :1.0,1.0a
Issue type        : kbbug
Solution Type     : kbfix

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