Q35248: No Data Type for 80-Bit Precision IEEE Real Numbers in BASIC

Article: Q35248
Product(s): See article
Version(s): 3.00 4.00 4.00b 4.50
Operating System(s): MS-DOS
Keyword(s): ENDUSER | B_BasicCom | mspl13_basic
Last Modified: 16-DEC-1989

QuickBASIC's implementation of the ANSI/IEEE Standard 754-1985 for
binary floating-point arithmetic includes two types of real numbers:

   Single-precision numbers, which use 32 bits (4 bytes)
   Double-precision numbers, which use 64 bits (8 bytes)

The ANSI/IEEE standard also describes an 80-bit (10-byte)
floating-point format called Double Extended. QuickBASIC's
intermediate calculations are performed in the 80-bit format for
greater accuracy, but the results are stored in single- or
double-precision variables. There is no data type in QuickBASIC
associated with the 80-bit format.

This article applies to the following products, which use IEEE binary
floating-point arithmetic:

1. Microsoft QuickBASIC Versions 3.00 (QB87.EXE only), 4.00, 4.00b,
   and 4.50 for the IBM PC

2. Microsoft BASIC Compiler Versions 6.00 and 6.00b for MS OS/2 and
   MS-DOS

3. Microsoft BASIC PDS Version 7.00 for MS-DOS and MS OS/2

ANSI is an acronym for the American National Standards Institute. IEEE
is an acronym for the Institute of Electrical and Electronics
Engineers, Inc., which can be reached at the following address:

   IEEE
   345 East 47th Street
   New York, NY 10017 USA

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.

Copyright Microsoft Corporation 1986-2002.