Microsoft KB Archive/35827

IEEE vs. Microsoft Binary Format; Rounding Issues PSS ID Number: Q35827 Article last modified on 05-02-1991 PSS database name: B_QuickBas

4.00 4.00b 4.50

MS-DOS

Summary:

An application note is available in the Software/Data Library that discusses the following subjects:

1. Why Microsoft uses the IEEE Floating Point format instead of the Microsoft Binary Format (MBF) in the following products:

   Microsoft QuickBASIC versions 4.00, 4.00b, and 4.50 for the IBM PC; Microsoft BASIC Compiler versions 6.00 and 6.00b for MS-DOS and MS OS/2; Microsoft BASIC PDS version 7.00 for MS-DOS and MS OS/2.

2. Differences between IEEE floating-point format and the Microsoft Binary Format (MBF). Numeric rounding issues in IEEE. (For more information, please search for a separate article with the following words:

   IEEE and tutorial and rounding

3. Microsoft plans to use IEEE instead of Microsoft Binary Format (MBF) in the future.

This application note can be found in the Software/Data Library by searching for the file QBIEEE, the Q number of this article, or S12037. QBIEEE was archived using the PKware file-compression utility.

A printed copy of this application note, titled “IEEE and Rounding,” can be also obtained from Microsoft Product Support Services.

More Information:

The design of IEEE format often causes BASIC to return floating-point results different than you might expect, as explained in many separate articles found with the following query:

floating and point and format and QuickBASIC

Copyright Microsoft Corporation 1991.