BUG: Causes of A2042 During Data Initialization

• Microsoft Macro Assembler for MS-DOS, versions 6.0, 6.0a, 6.0b, 6.1, 6.1a, and 6.11
• Microsoft Macro Assembler for OS/2, versions 6.0, 6.0a, and 6.0b

SYMPTOMS

Attempting to initialize a STRUCT or an array with a single data statement may generate the following error when too many initialization values are used:

   error A2042: statement too complex

CAUSE

The error is produced because the token limit for that particular line has been exceeded. This limit may also be exceeded by lines that are extended using the backslash ("\") character or the comma, as shown in the sample code below.

RESOLUTION

Do not attempt to initialize a struct on a single line that contains more than 99 tokens, commas, numbers, and so forth.

The data statement can be broken into several statements as shown by the array D2 in the sample below. Consecutive data items specified in this way are allocated in memory exactly as they would be if they were in a single data declaration.

STATUS

Microsoft has confirmed this to be a problem in the Microsoft Macro Assembler (MASM) versions 6.x. We are researching this problem and will post new information here in the Microsoft Knowledge Base as it becomes available.

MORE INFORMATION

Sample Code

In the sample code below, there are 97 tokens in the line where test_struct0 is declared on a single text line. This line assembles without a problem. The initialization of test_struc1, however, causes error A2042 to be generated. test_struc1 has 99 tokens, which causes the error A2042 to be produced. test_struct2 and test_struct3 are multiple-line demonstrations of the same problem.

The array d1 illustrates the same problem for an array of WORD. Array d2 shows a workaround.

; assembly options needed: /c .MODEL SMALL,C .DATA

prob_struct STRUCT 2 element WORD 60 DUP(0) prob_struct ENDS

; test_struct0 and test_struct1 should be single lines; they were ; broken for readability. Reassemble them to a single line.

test_struct0 prob_struct {{0,1,2,3,4,5,6,7,8,9,0,1,2,3,4,5,6,7,8,9,0,

                           1,2,3,4,5,6,7,8,9,0,1,2,3,4,5,6,7,8,9,0,1,
                           2,3,4,5,6,7}} ; no error

                           1,2,3,4,5,6,7,8,9,0,1,2,3,4,5,6,7,8,9,0,1,
                           2,3,4,5,6,7,8}} ; error produced

                           0,1,2,3,4,5,6,7,8,9,0,1,2,3,4,5,6,7,8,9,
                           0,1,2,3,4,5,6,7}} ; no error

                           0,1,2,3,4,5,6,7,8,9,0,1,2,3,4,5,6,7,8,9,
                           0,1,2,3,4,5,6,7,8}} ; error produced

         21,2,3,4,5,6,7,8,9,30,31,2,3,4,5,6,7,8,9,
         40,41,2,3,4,5,6,7,8,9

d2 WORD 1,2,3,4,5,6,7,8,9,10,11,2,3,4,5,6,7,8,9,20,

        21,2,3,4,5,6,7,8,9,30,31,2,3,4,5,6,7,8,9,40,
        41,2,3,4,5,6,7,8
   WORD 9

END