Macro Repetitions

Macro repetition specifies the repetition of a directive specified several times. For this purpose, the REPT directive is used, for example:

 A EQU 10       REPT 100       DB  A     ENDM 

This will generate 100 DB 10 directives. It is convenient to use the = operator with this directive, because it allows you to change the variable value multiple times, for example, using expressions like A = A + 5 .

The IRP directive has the following format:

 IRP parameter, <list>     ...     ENDM 

The block will be called the number of times corresponding to the number of parameters in the list. For example:

 IRP    REG,  <EAX, EBX,  ECX, EDX, ESI, EDI>     PUSH   REG     ENDM 

This will generate the following lines of code:

 PUSH   EAX     PUSH   EBX     PUSH   ECX     PUSH   EDX     PUSH   ESI     PUSH   EDI 

The IRPC directive is as follows :

 IRPC  parameter, cstring     Operators     ENDM 

For example:

 IRPC   CHAR,  azklg     CMP    AL,  '&CHAR&'     JZ    EndC     ENDM     EndC: 

This fragment is the equivalent of the following sequence:

 CMP  AL,  'a'        JZ   EndC        CMP  AL,  'z'        JZ   EndC        CMP  AL,  'k'        JZ   EndC        CMP  AL,  'l'        JZ   EndC        CMP  AL,  'g'        JZ   EndC     EndC: 

The & character in the latter example is used to specify that the parameter of the repeat block must be computed even within the quotation marks. The & character stands for the macro operation that works within the repeat block, because repeat blocks are one of the types of macro commands.