9.22.4 Assembler Directives

The 68HC11 and 68HC12 version of as have the following specific assembler directives:

.relax

The relax directive is used by the ‘GNU Compiler’ to emit a specific relocation to mark a group of instructions for linker relaxation. The sequence of instructions within the group must be known to the linker so that relaxation can be performed.

.mode [mshort|mlong|mshort-double|mlong-double]

This directive specifies the ABI. It overrides the ‘-mshort’, ‘-mlong’, ‘-mshort-double’ and ‘-mlong-double’ options.

.far symbol

This directive marks the symbol as a ‘far’ symbol meaning that it uses a ‘call/rtc’ calling convention as opposed to ‘jsr/rts’. During a final link, the linker will identify references to the ‘far’ symbol and will verify the proper calling convention.

.interrupt symbol

This directive marks the symbol as an interrupt entry point. This information is then used by the debugger to correctly unwind the frame across interrupts.

.xrefb symbol

This directive is defined for compatibility with the ‘Specification for Motorola 8 and 16-Bit Assembly Language Input Standard’ and is ignored.