A data processing apparatus includes plural data registers, an arithmetic logic unit and a status register. The status register stores a plurality of different types of status bits. These status bits could be a negative status bit, a carry status bit, an overflow status bit and a zero status bit. These...http://www.google.com.tw/patents/US6173394?utm_source=gb-gplus-share專利 US6173394 - Instruction having bit field designating status bits protected from modification corresponding to arithmetic logic unit result
