text: /*	$OpenBSD: btvar.h,v 1.5 2003/06/02 23:27:53 millert Exp $	*/
  /*	$NetBSD: btvar.h,v 1.2 1994/11/20 20:51:56 deraadt Exp $ */
  
  /*
   * Copyright (c) 1993
   *	The Regents of the University of California.  All rights reserved.
   *
   * This software was developed by the Computer Systems Engineering group
   * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
   * contributed to Berkeley.
   *
   * All advertising materials mentioning features or use of this software
   * must display the following acknowledgement:
   *	This product includes software developed by the University of
   *	California, Lawrence Berkeley Laboratory.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   * 3. Neither the name of the University nor the names of its contributors
   *    may be used to endorse or promote products derived from this software
   *    without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   *
   *	@(#)btvar.h	8.2 (Berkeley) 1/21/94
   */
  
  /*
   * Brooktree color frame buffer state variables (see btreg.h).
   *
   * Unfortunately, remarkably little code can be shared between the
   * cg3 and cg6 drivers here, as the cg3 registers do longword-ops
   * `as expected', but the cg6 ones use only the upper byte.
   *
   * Still, the software color map manipulation is not completely trivial.
   */
  union bt_cmap {
  	u_char  cm_map[256][3];		/* 256 R/G/B entries */
  	u_int   cm_chip[256 * 3 / 4];	/* the way the chip gets loaded */
  };
  
  /*
   * Routines in bt_subr.c.
   */
  int	bt_getcmap(union bt_cmap *, struct wsdisplay_cmap *);
  int	bt_putcmap(union bt_cmap *, struct wsdisplay_cmap *);
  void	bt_loadcmap(union bt_cmap *, volatile struct bt_regs *,
      u_int, u_int, int);
  void	bt_setcolor(union bt_cmap *, volatile struct bt_regs *,
      u_int, u_int8_t, u_int8_t, u_int8_t, int);
  
  /*
   * Compute (x / 4) * 3 and (x / 4) * 4.  These are used in turning
   * RGB indices (which are in multiples of three) into `chip RGB' values
   * (which are in multiples of four).
   */
  #define	BT_D4M3(x) ((((x) >> 2) << 1) + ((x) >> 2))	/* (x / 4) * 3 */
  #define	BT_D4M4(x) ((x) & ~3)				/* (x / 4) * 4 */
  