Table of Contents Previous topic Next topic
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 MVI \0,60H MVI \1,52H\.0 DCR \0 JNZ \.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 MVI \0,60H 12 MVI \1,52H 13 \.0 DCR \0 14 JNZ \.0 15 ENDM 16 17 ; This is the macro call: 18 19 macxampl A,B 6000 3E 60 MVI A,60H 6002 06 52 MVI B,52H 6004 3D .00000 DCR A 6005 C2 04 60 JNZ .00000 20 21Assembly completeTotal bytes generated: 80 errors0 warningsSymbol table:.00000 6004 1 symbols.