usr/src/sys/sparc/sbus/btvar.h

/*
 * 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.
 *
 * %sccs.include.redist.c%
 *
 *      @(#)btvar.h     8.2 (Berkeley) %G%
 *
 * from: $Header: btvar.h,v 1.1 93/10/12 15:29:01 torek Exp $
 */

/*
 * 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 __P((struct fbcmap *, union bt_cmap *, int));
int     bt_putcmap __P((struct fbcmap *, union bt_cmap *, 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 */