Microsoft KB Archive/11343

Assemble Problem with FMUL and FADD ID Number: Q11343

4.00 MS-DOS buglist4.00 fixlist5.00

Problem:

MASM assembles the following instructions, which are incorrect and should be flagged as errors:

fmul st(1), st(1) fadd st(2), st(1)

Response:

The instructions are invalid and should not be assembled. The instructions are being assembled as if the second argument were “st”, which would make them valid mnemonics, as the following “.lst” shows:

9B DC C9 fmul st(1), st 9B DC CA fmul st(2), st 9B DC C1 fadd st(1), st

9B DC C9 fmul st(1), st(1) 9B DC CA fmul st(2), st(1) 9B DC C1 fadd st(1), st(2)

Microsoft has confirmed this to be a problem in Version 4.00. This problem was corrected in Version 5.00.