On 680x0 family only.

Address Register indirect With postincrement:

When using the stack pointer (A7) with byte size data, the register
is incremented by two.

Address Register indirect With predecrement:

When using the stack pointer (A7) with byte size data, the register
is decremented by two.

Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Reviewed-by: Thomas Huth <huth@tuxfamily.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Message-Id: <1484332593-16782-6-git-send-email-laurent@vivier.eu>