Fujitsu MB91F109 FR30 Hardware Manual page 402

APPENDIX A I/O Maps
<Note>
Do not execute RMW instructions for registers for which a write-only bit is set.
RMW instructions (RMW: Read Modify Write)
AND Rj, @Ri
ANDH Rj, @Ri
ANDB Rj, @Ri
BANDL #u4, @Ri
BANDH #u4, @Ri
Data in areas marked as "Reserved" or "-" is undefined.
378
OR Rj, @Ri
ORH Rj, @Ri
ORB Rj, @Ri
BORL #u4, @Ri
BORH #u4, @Ri
EOR Rj, @Ri
EORH Rj, @Ri
EORB Rj, @Ri
BEORL #u4, @Ri
BEORH #u4, @Ri