CFREG_BITBLT_SRC_LOW
cfxga_write_2(sc, CFREG_BITBLT_SRC_LOW, pos);
cfxga_write_2(sc, CFREG_BITBLT_SRC_LOW, srcpos);
cfxga_write_2(sc, CFREG_BITBLT_SRC_LOW, font->fontwidth <= 8 ? 0 : 1);