5.9.4 .macro symbol arg₁[=default]
 [, ..., arg_n [=default] ]
...
.endm

Define macros that generate assembly output. A macro accepts optional arguments and can call other macros or even itself recursively.

If a macro definition requires arguments, specify their names after the macro name, separated by commas or spaces. To refer to arguments within the macro block, use \arg or &arg&. The second form can be used to combine an argument with additional characters to create a symbol name.

For example, assembling:

.macro display_int sym
  mov \sym,w0
  rcall display
.endm

display_int result

is equivalent to assembling:

mov result,w0
rcall display

In the next example, a macro is used to define HI- and LO-word constants for a 32-bit integer.

       .macro LCONST name,value
       .equ \name,\value
       .equ &name&LO,(\value) & 0xFFFF
       .equ &name&HI,((\value)>>16) & 0xFFFF
       .endm

       LCONST seconds_per_day 60*60*24

       mov #seconds_per_dayLO,w0
       mov #seconds_per_dayHI,w1

xc-dsc-as maintains a counter of how many macros have been executed in the psuedo-variable \@. This value can be copied to the assembly output, but only within a macro definition. In the following example, a recursive macro is used to allocate an arbitrary number of labeled buffers.

       .macro make_buffers num,size
BUF\@: .space \size
       .if (\num - 1)
       make_buffers (\num - 1),\size
       .endif
       .endm

       .bss
       make_buffers 4,16 ; create BUF0..BUF3, 16 bytes each