public void handler() {
            int t, r;
            t=EXTBYTE();
            r = (m6800.a + t)&0xFFFF;
            CLR_HNZVC();
            SET_FLAGS8(m6800.a, t, r);
            SET_H(m6800.a, t, r);
            m6800.a = r & 0xFF;
        }