KnowledgeBase Archive

An Archive of Early Microsoft KnowledgeBase Articles

View on GitHub

Q106561: FIX: Debug: Single-Step Fails with Emulated Float Intructions

Article: Q106561
Product(s): Microsoft Fortran Compiler
Version(s): 1.0
Operating System(s): 
Keyword(s): 
Last Modified: 24-MAR-2000

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

- Microsoft FORTRAN PowerStation for MS-DOS, version 1.0 
-------------------------------------------------------------------------------

SYMPTOMS
========

When using the debugger, attempting to use the Step Into (F8) or Step Over (F10)
function causes execution to the next breakpoint (or to the end of the program
if no breakpoints are encountered).

CAUSE
=====

The debugger treats the Step commands similar to the Go (F5) command when
stepping into or over an assembler floating-point instruction. This error occurs
only when using floating-point emulation and does not occur when using a math
coprocessor.

STATUS
======

Microsoft has confirmed this to be a problem in FORTRAN PowerStation version 1.0
for MS-DOS. This problem has been resolved with FORTRAN PowerStation maintenance
release version 1.0a for MS-DOS.

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

FORTRAN PowerStation version 1.0 can be differentiated from the maintenance
release version 1.0a by invoking the linker. Typing "link32 | more" (without the
quotation marks) from \F32\BIN directory will show version 2.8 for FORTRAN
PowerStation version 1.0, and it will show version 1.0f for the maintenance
release version 1.0a.

To demonstrate the problem:

1. Disable the PowerStation's use of the coprocessor (if present). This is done
  by typing the following command before starting Windows:

  " set tnt=-fpem " (without the quotation marks)

2. Start Windows and the FORTRAN Visual Workbench.

3. Build a project with F32\DEBUGME


4. Set breakpoints at lines 22 and 26 of F32\DEBUGME\DEBUGME.FOR:

        MyReal4 = MyInt4 * 3.14159

  -and-

        If ((MyInt4 * MyReal4) .EQ. MyReal8) Then

5. Press F5 to "GO"; the current line will be 22.

6. Single-step (press F8 or F10); the next line (24) is skipped and the debugger
  will go to the breakpoint on line 26.

To see what is happening in more detail, after step 5, turn on display of mixed
source and assembly from the View menu (or with the command CTRL+F7).

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

======================================================================
Keywords          :  
Technology        : kbAudDeveloper kbFortranSearch kbZNotKeyword3 kbFORTRANPower100DOS
Version           : :1.0
Issue type        : kbbug
Solution Type     : kbfix

=============================================================================

THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY.