Microsoft KB Archive/37301

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Why QuickBASIC's "Generate 68881 Code" Option Dims Out

Article ID: 37301

Article Last Modified on 11/21/2006

This article was previously published under Q37301


In the compiler Options... choice on the Run menu of Macintosh QuickBASIC, the "Generate 68881 Code" check box is disabled (marked in dim letters) until you click the "Generate 68020 Code" check box in the Binary Math version. In the Decimal Math version, the "Generate 68881 Code" check box remains permanently disabled because Microsoft QuickBASIC (d) cannot take advantage of the coprocessor.

This feature prevents you from generating 68881 instructions for a machine that could not have this chip.

To generate code that takes advantage of the 68881 math coprocessor, do the following:

  1. Run Microsoft QuickBASIC (b), Binary Math version.
  2. Click the box labeled "Generate 68020 Code."
  3. Click the box labeled "Generate 68881 Code."

A program compiled with the 68020 and 68881 options requires the presence of the 68881 math-coprocessor chip at run time.


The 68881 chip must not be on an accelerator board; it must be built into the Macintosh as standard equipment. QuickBASIC has not been tested with accelerator boards.

Additional query words: MQuickB

Keywords: KB37301