RTEMS CPU Architecture Supplement
The MC68xxx architecture supports a simple yet effective call and
return mechanism. A subroutine is invoked via the branch to subroutine
(bsr) or the jump to subroutine (jsr) instructions.
These instructions push the return address on the current stack.
The return from subroutine (rts) instruction pops the return
address off the current stack and transfers control to that instruction.
It is is important to note that the MC68xxx call and return mechanism does
not automatically save or restore any registers. It is the responsibility
of the high-level language compiler to define the register preservation
and usage convention.
RTEMS CPU Architecture Supplement
Copyright © 1988-2008 OAR Corporation