9.24.4 Assembler Directives The 68HC11 and 68HC12 version of as
have the following specific assembler directives: - 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. -
This directive specifies the ABI. It overrides the `-mshort',
`-mlong', `-mshort-double' and `-mlong-double' options. - 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. -
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. - This directive is defined
for compatibility with the `Specification for Motorola 8 and
16-Bit Assembly Language Input Standard'