The r0 register holds the system_off function pointer. As r0 is a scratch
register, the pointer needs to moved to a preserved register before
branching to a (custom) marker function.
Furthermore, in accordance to rule 6.2.1.2 of aapcs32, the stack pointer
needs to align on 8 bytes. Hence r0 is pushed to the stack in addition to
the lr register, before calling the public interface of checking the
s2ram marker.
Signed-off-by: Hessel van der Molen <hvandermolen@dexels.com>
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