Macro directives

Description

Operation

The .macro directive defines a new macro with name macro_name, and zero or more named parameters. The body of the macro extends to the matching .endm directive.

Once a macro is defined, it can be instantiated by using it like an instruction mnemonic:

macro_name argument[, argument]...

Inside a macro body, \@ expands to a counter value which is unique to each macro instantiation. This value can be used to create unique label names, which does not interfere with other instantiations of the same macro.

The .exitm directive allows exiting a macro instantiation before reaching the end.

Examples

    // Macro for defining global variables, with the symbol binding, type and
    // size set appropriately. The 'value' parameter can be omitted, in which
    // case the variable gets an initial value of 0. It is an error to not
    // provide the 'name' argument.
    .macro global_int, name:req, value=0
    .global \name
    .type \name, %object
    .size \name, 4
  \name:
    .word \value
    .endm

    .data
    global_int foo
    global_int bar, 42