mpic_tm_read
reg = mpic_tm_read(src - mpic->timer_vecs[0]) &
mpic_tm_write(src, mpic_tm_read(src) & ~MPIC_VECPRI_MASK);
mpic_tm_read(src);
mpic_tm_write(src, mpic_tm_read(src) | MPIC_VECPRI_MASK);
mpic_tm_read(src);