Microsoft Binary Format

In computing, Microsoft Binary Format (MBF) was a format for floating point numbers used in Microsoft's BASIC language products including MBASIC, QuickBasic and GW-BASIC.^[1]

MBF double-precision numbers consist of a sign bit, an eight bit exponent and a 55 bit significand, providing slightly more precison than the IEEE 754 format, but less scale.^[2][3]

By the time Visual Basic was released, the IEEE 754 standard had become widely adopted - for example, it was incorporated into Intel's 387 coprocessor and every x86 processor from the 486 on. Visual Basic uses the IEEE 754 format instead of MBF.

See also

Microsoft provides a 16 bit dynamic link library with C source code containing functions to convert MBF data to IEEE 754.

MBF to IEEE function written in Python

MBF to IEEE conversion functions in C/C++ stolen from old Microsoft supported code.

See also

Computer Science portal

• Floating point
• IEEE 754 — Standard for Binary Floating-Point Arithmetic
• IBM Floating Point Architecture

Notes and references

1. ^ "IEEE vs. Microsoft Binary Format; Rounding Issues (Complete)". Microsoft Support. November 21, 2006. http://support.microsoft.com/kb/35826. Retrieved February 24, 2010. 
2. ^ "IEEE vs. Microsoft Binary Format; Rounding Issues (Complete)". Microsoft Support. November 21, 2006. http://support.microsoft.com/kb/35826. Retrieved February 24, 2010. 
3. ^ "Need to access MBF (Microsoft Binary Format) data". Experts Exchange. December 11, 2001. http://www.experts-exchange.com/Programming/Languages/Pascal/Delphi/Q_20245266.html. Retrieved February 24, 2010.