RTEMS Motorola MC68xxx Applications Supplement
As discussed above, the bsr and jsr instructions do not automatically save any registers. RTEMS uses the registers D0, D1, A0, and A1 as scratch registers. These registers are not preserved by RTEMS directives therefore, the contents of these registers should not be assumed upon return from any RTEMS directive.
RTEMS Motorola MC68xxx Applications Supplement
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