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p8init.c
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1993-12-06
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/**
** P8INIT.C
**
** Copyright (C) 1992, Csaba Biegl
** 820 Stirrup Dr, Nashville, TN, 37221
** csaba@vuse.vanderbilt.edu
**
** This file is distributed under the terms listed in the document
** "copying.cb", available from the author at the address above.
** A copy of "copying.cb" should accompany this file; if not, a copy
** should be available from where this file was obtained. This file
** may not be distributed without a verbatim copy of "copying.cb".
** You should also have received a copy of the GNU General Public
** License along with this program (it is in the file "copying");
** if not, write to the Free Software Foundation, Inc., 675 Mass Ave,
** Cambridge, MA 02139, USA.
**
** This program is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
** GNU General Public License for more details.
**/
#include "p8.h"
#include "grdriver.h"
/*
* An element of this table gets XOR-ed with the significant bits of
* the color. It has to be drawn only if the result is nonzero
*/
int _GrP8DrawTable[4] = {
~C_SIGNIF, /* C_SET -- always draw */
0, /* C_XOR -- draw only if non-zero */
0, /* C_OR -- draw only if non-zero */
C_SIGNIF /* C_AND -- draw only if not all 1-s */
};
int _GrP8LmaskTable[] = { 0, 0x0e, 0x0c, 0x08 };
int _GrP8RmaskTable[] = { 0, 0x01, 0x03, 0x07 };
int _GrP8Chain4Off;
int _GrP8Chain4On;
char _GrP8PlanarModeOn;
char _GrP8UsePlanarMode;
void _GrP8Init(int accesstype)
{
_GrP8UsePlanarMode = FALSE;
if(accesstype == GRD_8_F_PLANES) {
__READ_VGA_REG__(VGA_SEQUENCER_PORT,4,_GrP8Chain4On);
_GrP8Chain4Off = _GrP8Chain4On & ~8;
_GrP8Chain4Off = (_GrP8Chain4Off << 8) | 4;
_GrP8Chain4On = (_GrP8Chain4On << 8) | 4;
_GrP8PlanarModeOn = FALSE;
_GrP8UsePlanarMode = TRUE;
}
}