FIX: .IF with Multiple Tests Adds a JMP Instruction

Last reviewed: September 18, 1997
Article ID: Q120067

6.10 MS-DOS kbtool kbfixlist kbbuglist

The information in this article applies to:

Microsoft Macro Assembler (MASM) for MS-DOS, version 6.1

SYMPTOMS

If two or more values known at assembly time evaluate as TRUE, .IF (below) will add a JMP instruction. In this first example, only the NOP is assembled:

   .IF 1
      nop
   .ENDIF

In this second example, a JMP instruction is added:

   .IF 1 || 3
      nop
   .ENDIF

If you use a register, as in this third example, the result is a conditional JMP to the location following the .IF:

   .IF ax || 3
      nop
   .ENDIF

The code runs as expected, despite the extra instructions.

RESOLUTION

To eliminate the extra generated code, replace the "||" with an "OR".

STATUS

Microsoft has confirmed this to be a bug in MASM version 6.1. This problem was corrected in MASM version 6.11.

Additional reference words: 6.10 buglist6.10 fixlist6.11
KBCategory: kbtool kbfixlist kbbuglist
KBSubCategory: MLIss
Solution Type : kbfix

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Last reviewed: September 18, 1997
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