FIX: Nested Structures May Hang Macro Assembler 6.0

The information in this article applies to:

• Microsoft Macro Assembler for MS-DOS, version 6.0
• Microsoft Macro Assembler for OS/2, version 6.0

SYMPTOMS

Nested structures may cause the Microsoft Macro Assembler (MASM) version 6.0 to hang when one structure contains a field of the type of another structure and it is initialized. The code below demonstrates the problem more clearly.

RESOLUTION

Pad the initializer to make it the size declared. In the sample code below, padding the initializer for the member called People to three characters corrects the problem.

STATUS

Microsoft has confirmed this to be a problem in MASM version 6.0. This problem was corrected in MASM version 6.0a.

MORE INFORMATION

In the sample code, notice that the structure member Nme has a length of three bytes. However, the structure called People initializes its Nme member to 'R', which is one character instead of three. This produces the problem.

Under MS-DOS, the assembler logo will appear, and the system will hang. Under OS/2, the following message appears:

   The process has stopped.
   The software diagnostic code (trap number) is  013.

Sample Code

; Assemble options needed: /c

.MODEL small

aStruct STRUCT

    Nme BYTE 3 DUP (?)

bStruct STRUCT

    People aStruct <'R'>

;   People aStruct <'R  '>    ; 'R' is followed by two spaces

.DATA

    Crash bStruct { }