NetBSD/sys/arch/sparc/dev/btreg.h

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/* $NetBSD: btreg.h,v 1.2 1994/11/20 20:51:55 deraadt Exp $ */
/*
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* 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. 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, Berkeley and its contributors.
* 4. 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.
*
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* @(#)btreg.h 8.2 (Berkeley) 1/21/94
*/
/*
* Several Sun color frame buffers use some kind of Brooktree video
* DAC (e.g., the Bt458, -- in any case, Brooktree make the only
* decent color frame buffer chips).
*
* Color map control on these is a bit funky in a SPARCstation.
* To update the color map one would normally do byte writes, but
* the hardware takes longword writes. Since there are three
* registers for each color map entry (R, then G, then B), we have
* to set color 1 with a write to address 0 (setting 0's R/G/B and
* color 1's R) followed by a second write to address 1 (setting
* color 1's G/B and color 2's R/G). Software must therefore keep
* a copy of the current map.
*
* The colormap address register increments automatically, so the
* above write is done as:
*
* bt->bt_addr = 0;
* bt->bt_cmap = R0G0B0R1;
* bt->bt_cmap = G1B1R2G2;
* ...
*
* Yow!
*
* Bonus complication: on the cg6, only the top 8 bits of each 32 bit
* register matter, even though the cg3 takes all the bits from all
* bytes written to it.
*/
struct bt_regs {
u_int bt_addr; /* map address register */
u_int bt_cmap; /* colormap data register */
u_int bt_ctrl; /* control register */
u_int bt_omap; /* overlay (cursor) map register */
};