Microsoft KB Archive/26817

MOV EAX Not Flagged ID Number: Q26817

5.00 MS-DOS buglist5.00

Problem:

The following code assembles with no error messages but is not a valid MASM instruction. The opcode generated is for another instruction, MOV DS,AX.

MOV DS,EAX

The 386 register EAX cannot be used in a MOV instruction with any general registers. Special debugging registers can be used with EAX. See your INTEL 386 instruction specification for details.

Response:

Microsoft has confirmed this to be a problem in Version 5.00. This problem was corrected in MASM Version 5.00a. Please call Microsoft Product Support Services at (206) 646-5109 and request an update to MASM Version 5.00a.