RTEMS Motorola MC68xxx Applications 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 Motorola MC68xxx Applications Supplement
Copyright © 1988-2004 OAR Corporation