igs_ext_read
curctl = igs_ext_read(iot, ioh, IGS_EXT_SPRITE_CTL);
busctl = igs_ext_read(dc->dc_iot, dc->dc_ioh, IGS_EXT_BUS_CTL);
curctl = igs_ext_read(dc->dc_iot, dc->dc_ioh, IGS_EXT_SPRITE_CTL);
reg = igs_ext_read(iot, ioh, IGS_EXT_SPRITE_CTL);
reg = igs_ext_read(iot, ioh, IGS_EXT_SPRITE_CTL);