1 /* 2 * Copyright (c) 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This software was developed by the Computer Systems Engineering group 6 * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and 7 * contributed to Berkeley. 8 * 9 * All advertising materials mentioning features or use of this software 10 * must display the following acknowledgement: 11 * This product includes software developed by the University of 12 * California, Lawrence Berkeley Laboratory. 13 * 14 * %sccs.include.redist.c% 15 * 16 * @(#)btvar.h 8.2 (Berkeley) 01/21/94 17 * 18 * from: $Header: btvar.h,v 1.1 93/10/12 15:29:01 torek Exp $ 19 */ 20 21 /* 22 * Brooktree color frame buffer state variables (see btreg.h). 23 * 24 * Unfortunately, remarkably little code can be shared between the 25 * cg3 and cg6 drivers here, as the cg3 registers do longword-ops 26 * `as expected', but the cg6 ones use only the upper byte. 27 * 28 * Still, the software color map manipulation is not completely trivial. 29 */ 30 union bt_cmap { 31 u_char cm_map[256][3]; /* 256 R/G/B entries */ 32 u_int cm_chip[256 * 3 / 4]; /* the way the chip gets loaded */ 33 }; 34 35 /* 36 * Routines in bt_subr.c. 37 */ 38 int bt_getcmap __P((struct fbcmap *, union bt_cmap *, int)); 39 int bt_putcmap __P((struct fbcmap *, union bt_cmap *, int)); 40 41 /* 42 * Compute (x / 4) * 3 and (x / 4) * 4. These are used in turning 43 * RGB indices (which are in multiples of three) into `chip RGB' values 44 * (which are in multiples of four). 45 */ 46 #define BT_D4M3(x) ((((x) >> 2) << 1) + ((x) >> 2)) /* (x / 4) * 3 */ 47 #define BT_D4M4(x) ((x) & ~3) /* (x / 4) * 4 */ 48