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CROSS ASSEMBLER->Assembler Macros->Dummy Labels

If you include an ordinary label in the macro definition then, except where it is being defined using the SET directive, it will only be possible to call that macro once. A second call will generate a duplicate label error. Dummy labels overcome this problem. Dummy labels are \.0 to \.9 and \.A to \.Z (or \.a to \.z since the dummy labels are case insensitive). These symbols are used within the macro definition in place of ordinary labels, and when the macro is expanded the assembler replaces them with labels .00000, .00001, .00002 etc. Unique labels are therefore generated each time the macro is called.

The following example illustrates the use of dummy labels.

Firstly the source code listing:

    NAM    MACXAMPL
    TTL    *** Dummy Labels ***
    LIST
    SYM
    MEX
    ORG 6000H

* This is the macro definition:

macxampl MACR
        LDA\0 $60
        LDA\1 $52
\.0      A\1\0
        BNE \.0
        ENDM

* This is the macro call:

        macxampl A,B

And now the listing generated during assembly:

   1                           NAM     MACXAMPL
   2                           TTL     *** Dummy Labels ***
   3                           LIST
   4                           SYM
   5                           MEX
   6 6000                      ORG     6000H
   7
   8                 * This is the macro definition:
   9
  10                 macxampl MACR
  11                          LDA\0 $60
  12                          LDA\1 $52
  13                 \.0      A\1\0
  14                          BNE \.0
  15                          ENDM
  16
  17                 * This is the macro call:
  18
  19                           macxampl A,B
     6000 96 60                LDAA    $60
     6002 D6 52                LDAB    $52
     6004 1B         .00000    ABA
     6005 26 FD                BNE     .00000
  20
  21
Assembly complete
Bytes filed: 7
0 errors
0 warnings