List of Basics Using MBF versus IEEE Floating-Point Format (11936)




This article was previously published under Q11936

SUMMARY

This article lists which Basic versions (for MS-DOS) use Microsoft Binary Format (MBF) and which versions use IEEE format for storing single- and double-precision floating-point numbers.

MORE INFORMATION

Single- and double-precision real numbers are stored in the Microsoft Binary Format (MBF) in the following languages:

  1. QuickBasic versions 1.00, 1.01, 1.02, 2.00, 2.01, and the non-coprocessor QB.EXE version 3.00, for MS-DOS
  2. IBM and Compaq BasicA Interpreters (BasicA.COM) for MS-DOS
  3. GW-Basic Interpreter versions 3.20, 3.22, and 3.23 (GWBasic.EXE) for MS-DOS
  4. Microsoft Basic Interpreter version 5.28 for MS-DOS
  5. Microsoft Basic Compiler versions 5.35 and 5.36 for MS-DOS
QuickBasic versions 4.00, 4.00b, and 4.50 (QB.EXE, BC.EXE) and the coprocessor version of QuickBasic version 3.00 (QB87.EXE) use IEEE floating-point format for single- and double-precision real numbers.

Note that Microsoft Business Basic Compiler versions 1.00 and 1.10 use a different floating-point format called Decimal Math. Decimal Math is very slow but has no rounding or representation errors because numbers are stored in their exact decimal form, instead of in an approximate binary form. (Sales of Business Basic were discontinued.)

In QuickBasic version 3.00, the coprocessor version of QuickBasic uses IEEE format numbers. Conversion routines are provided in version 3.00 to convert between the MBF used in the non-coprocessor version (QB.EXE) and the IEEE floating-point format used in the coprocessor version (QB87.EXE).

QuickBasic versions 4.00, 4.00b, and 4.50; Microsoft Basic Compiler versions 6.00 and 6.00b; and Microsoft Basic Professional Development System (PDS) versions 7.00 and 7.10 only use IEEE format numbers, but conversion routines and a compiler switch are provided to convert between MBF and IEEE format. This conversion is necessary if you want to retrieve floating-point numbers from random access files that were created using MBF.

REFERENCES

For additional articles that discuss MBF and IEEE, search for the following words:

floating and point and format and QuickBasic

The IEEE floating point format is documented in the following manuals:

  1. Pages 16-21 of "Microsoft QuickBasic 4.0: Basic Language Reference" for QuickBasic versions 4.00 and 4.00b. Note that 4.00 manuals need a correction on page 19 in the MHex$ code example, as explained in a separate article found with the following query:

    MHex$ AND 19

  2. Pages 12-17 of "Microsoft QuickBasic 4.5: Basic Language Reference" for QuickBasic version 4.50. Note that this optional manual must be ordered separately using an order card provided with 4.50.
  3. Pages 702-705 of the "Microsoft Basic 7.0: Programmer's Guide" for Microsoft Basic PDS versions 7.00 and 7.10.
MBF is documented in a separate article found with the following query:

MBF AND conversion AND exponent

Modification Type: Minor Last Reviewed: 1/8/2003
Keywords: KB11936
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