rex3_write_go
rex3_write_go(dc, REX3_REG_ZPATTERN, pattern);
rex3_write_go(dc, REX3_REG_ZPATTERN, pattern);
rex3_write_go(dc, REX3_REG_XYENDI, (x2 << REX3_XYENDI_XSHIFT) | y2);
rex3_write_go(dc, REX3_REG_XYMOVE, tmp);