chipsfb_read_indexed
reg = chipsfb_read_indexed(sc, CT_CONF_INDEX, XR_PIXEL_PIPELINE_CTL_0);
width = chipsfb_read_indexed(sc, CT_FP_INDEX, FP_HSIZE_LSB);
width |= (chipsfb_read_indexed(sc, CT_FP_INDEX, FP_HORZ_OVERFLOW_1)
height = chipsfb_read_indexed(sc, CT_FP_INDEX, FP_VSIZE_LSB);
height |= (chipsfb_read_indexed(sc, CT_FP_INDEX, FP_VERT_OVERFLOW_1)