Microsoft KB Archive/117903

= FIX: Incorrect Floating-Point Calculations with /Ox and /Op =

PSS ID Number: 117903

Article Last Modified on 3/24/2000

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The information in this article applies to:


 * Microsoft FORTRAN PowerStation for MS-DOS 1.0

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This article was previously published under Q117903



SYMPTOMS
The program produces incorrect floating-point results when it is compiled using the /Ox and /Op optimizations (or /Oxp).



RESOLUTION
Do not use both /Ox and /Op when compiling.



STATUS
Microsoft has confirmed this to be a bug in FORTRAN PowerStation for MS-DOS, version 1.0. This problem was corrected in the FORTRAN PowerStation for MS-DOS maintenance release, version 1.0a.



MORE INFORMATION
FORTRAN PowerStation, version 1.0, can be differentiated from the maintenance release, version 1.0a, by invoking the linker. Typing link32 | more from the \F32\BIN directory will show version 2.8 for FORTRAN PowerStation, version 1.0, and will show version 1.0f for the maintenance release, version 1.0a.

The following sample program can be used to demonstrate this problem. The correct result is:

2.929688E-03

2.929688E-03

Sample Code
C compile options required: /Oxp

n1 = 1024 n2 = 512 c = (1./n1)+(1./n2) write (*,*) c  write (*,*) (1./n1)+(1./n2) end

Additional query words: 1.00 1.00a buglist1.00 fixlist1.00a

Keywords: kbbug KB117903

Technology: kbAudDeveloper kbFORTRANPower100DOS kbFortranSearch kbZNotKeyword3

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