Microsoft KB Archive/77078

= FIX: Whitespace Character Must Precede DUP Operator =

Article ID: 77078

Article Last Modified on 10/29/2003

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APPLIES TO


 * Microsoft Macro Assembler 6.0 Standard Edition
 * Microsoft Macro Assembler 6.0a
 * Microsoft Macro Assembler 6.0b

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This article was previously published under Q77078



SYMPTOMS
When using the DUP operator in the Microsoft Macro Assembler (MASM), you must place a whitespace character before the DUP operator if using the &quot;?&quot; operator. If no whitespace is present, no error message is produced by the assembler, and incorrect code will be generated. The assembler will generate one data item for the specified type, initialized to the value of the repeat size for the DUP operator.



RESOLUTION
To work around the problem, place a space between the repeat size and the DUP operator. Initializing the variable will cause a syntax error to be generated.



STATUS
Microsoft has confirmed this to be a problem in MASM version 6.0, 6.0a, and 6.0b. This problem was corrected in MASM for MS-DOS version 6.1.



MORE INFORMATION
The code example below generates a listing file that shows the size generated for the respective DUP statements. It can be seen that the first DUP operation generates 4 data bytes; however, the second generates 1 data byte initialized to 4.

The assembler has problems parsing this statement because the DUP operator begins with a letter (d), which is a valid radix suffix.

Sample Code
; Assemble options needed: /Fl

.MODEL small .STACK 4096

.DATA a      DB 4 DUP(0) size_a DB SIZEOF a b       DB 4DUP(?) size_b DB SIZEOF b

.CODE start: mov ax, 4C00H int 21H     ; Terminate Process END start

Additional query words: 6.00 6.00a 6.00b buglist6.00 buglist6.00a buglist6.00b fixlist6.10

Keywords: kbfix KB77078

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