FIX: COMM Directive Produces Error If Count Field Not Specified (74221)

SYMPTOMS

The Microsoft Macro Assembler (MASM) version 6.0 will produce a syntax error when multiple variables (separated by commas) are listed following a COMM directive if any variable, except the last one in the list, does not have a count field specified. For example, assembling sample code #1 with MASM 6.0 produces the following error:

error A2008: syntax error: dec

When assembling sample code #2, MASM 6.0 produces this error:

error A2008: syntax error: inc

RESOLUTION

The following methods may be used to work around these problems:

Place the count field with each variable specified. For example:

      COMM NEAR var1:word:1,var2:word:1,var3:word:3

-or-

Make multiple COMM statements. For example:

      COMM NEAR var1:word
      COMM NEAR var2:word

MORE INFORMATION

The sample code below illustrates this problem. MASM version 5.1 and 5.1a assemble the code without any errors. According to the BNF Grammar in Appendix B of the "Microsoft Macro Assembler Programmer's Guide," this should also assemble correctly with MASM version 6.0.

Sample Code #1

; Assemble options needed: none

.MODEL small
.DATA
  COMM NEAR var1:WORD,   var2:WORD    ; This doesn't work
; COMM NEAR var1:WORD:1, var2:WORD    ; This works
END

Sample Code #2

; Assemble options needed: none

.MODEL small
.DATA
  COMM NEAR var1:WORD,
            var2:WORD, var3:WORD      ; This doesn't work

; COMM NEAR var1:WORD:1,
;           var2:WORD:1, var3:WORD:1  ; This works
END