MC68HC908GP20 Datasheet, PDF (246/406 Pages) Freescale Semiconductor, Inc – M68HC08 Microcontrollers

During a subroutine call, the CPU uses two bytes of the stack to store
the return address. The stack pointer decrements during pushes and
increments during pulls.
NOTE:
Be careful when using nested subroutines. The CPU may overwrite data
in the RAM during a subroutine or during the interrupt stacking
operation.
Advance Information
246
MC68HC908GP20 — Rev 2.1
Freescale Semiconductor