CRTHiOrd
tmp = read3X4(par, CRTHiOrd) & 0x07;
write3X4(par, CRTHiOrd, tmp);
tmp = read3X4(par, CRTHiOrd) & 0xF8;
write3X4(par, CRTHiOrd, tmp | ((base & 0xE0000) >> 17));