BYTE_CLIP_MAX
p9100_ctl_write_4(sc, BYTE_CLIP_MAX, ((x + wi - 1) << 16) | 0x3fff);
p9100_ctl_write_4(sc, BYTE_CLIP_MAX, 0x3fff3fff);
p9100_ctl_write_4(sc, BYTE_CLIP_MAX, 0x3fff3fff);
p9100_ctl_write_4(sc, BYTE_CLIP_MAX, 0x3fff3fff);
p9100_ctl_write_4(sc, BYTE_CLIP_MAX, 0x3fff3fff);