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/*

 * Copyright (c) 1999, 2000 Greg Haerr <greg@censoft.com>

 *

 * 16 color 4 planes EGA/VGA Planar Video Driver for Microwindows

 * Portable C version

 *

 * Based on BOGL - Ben's Own Graphics Library.

 *   Written by Ben Pfaff <pfaffben@debian.org>.

 *       BOGL is licensed under the terms of the GNU General Public License

 *

 * In this driver, psd->linelen is line byte length, not line pixel length

 *

 * This file is meant to compile under Linux, ELKS, and MSDOS

 * without changes.  Please try to keep it that way.

 *

 */

/*#define NDEBUG*/

#if _MINIX

#include <ibm/portio.h>

#endif

#include <assert.h>

#include "device.h"

#include "vgaplan4.h"

#include "fb.h"

#if MSDOS | ELKS | __rtems__

/* assumptions for speed: NOTE: psd is ignored in these routines*/

#define SCREENBASE              EGA_BASE

#define BYTESPERLINE            80

#else

/* run on top of framebuffer*/

#define SCREENBASE              ((char *)psd->addr)

#define BYTESPERLINE            (psd->linelen)

#endif

/* Values for the data rotate register to implement drawing modes. */

static unsigned char mode_table[MWMODE_MAX + 1] = {

  0x00, 0x18, 0x10, 0x08,       /* COPY, XOR, AND, OR implemented*/

  0x00, 0x00, 0x00, 0x00,       /* no VGA HW for other modes*/

  0x00, 0x00, 0x00, 0x00,

  0x00, 0x00, 0x00, 0x00,

};

/* precalculated mask bits*/

static unsigned char mask[8] = {

        0x80, 0x40, 0x20, 0x10, 0x08, 0x04, 0x02, 0x01

};

#if HAVEIOPERM

static int

fbvga_setiopermissions(PSD psd)

{

        /* allow direct access to vga controller space*/

        return ioperm(0x3c0, 0x20, 1);

}

#endif

/* Init VGA controller, calc linelen and mmap size, return 0 on fail*/

int

ega_init(PSD psd)

{

#if HAVEIOPERM

        if(fbvga_setiopermissions(psd) == -1) {

                EPRINTF("Can't set i/o permissions: %m\n");

                return 0;

        }

        /*

         * Fill in entry point for applications to call to

         * regain i/o permissions.  This is required after

         * calling pthreads_create because pthreads resets

         * the i/o permissions after thread creation.

         * Note that this requires that systems using pthreads

         * and VGA16 framebuffer to run setuid root :-(

         */

        psd->SetIOPermissions = fbvga_setiopermissions;

#endif

#if MSDOS | ELKS | __rtems__

        /* fill in screendevice struct if not framebuffer driver*/

        psd->addr = SCREENBASE;         /* long ptr -> short on 16bit sys*/

        psd->linelen = BYTESPERLINE;

#endif

#if _MINIX

        psd->addr = 0;                   /* long ptr -> short on 16bit sys*/

        psd->linelen = 80;

#endif

        /* framebuffer mmap size*/

        psd->size = 0x10000;

        /* Set up some default values for the VGA Graphics Registers. */

        set_enable_sr (0x0f);

        set_op (0);

        set_mode (0);

        return 1;

}

/* draw a pixel at x,y of color c*/

void

ega_drawpixel(PSD psd,unsigned int x, unsigned int y, MWPIXELVAL c)

{

        assert (x >= 0 && x < psd->xres);

        assert (y >= 0 && y < psd->yres);

        assert (c < psd->ncolors);

        DRAWON;

        set_op(mode_table[gr_mode]);

        set_color (c);

        select_and_set_mask (mask[x&7]);

        RMW_FP ((FARADDR)SCREENBASE + (x>>3) + y * BYTESPERLINE);

        DRAWOFF;

}

/* Return 4-bit pixel value at x,y*/

MWPIXELVAL

ega_readpixel(PSD psd,unsigned int x,unsigned int y)

{

        FARADDR         src;

        int             plane;

        MWPIXELVAL      c = 0;

        assert (x >= 0 && x < psd->xres);

        assert (y >= 0 && y < psd->yres);

        DRAWON;

#if _MINIX

        src = (unsigned char *)(SCREENBASE + (x>>3) + y * BYTESPERLINE);

#else

        src = SCREENBASE + (x>>3) + y * BYTESPERLINE;

#endif

        for(plane=0; plane<4; ++plane) {

                set_read_plane(plane);

                if(GETBYTE_FP(src) & mask[x&7])

                        c |= 1 << plane;

        }

        DRAWOFF;

        return c;

}

/* Draw horizontal line from x1,y to x2,y including final point*/

void

ega_drawhorzline(PSD psd, unsigned int x1, unsigned int x2, unsigned int y,

        MWPIXELVAL c)

{

        FARADDR dst, last;

        assert (x1 >= 0 && x1 < psd->xres);

        assert (x2 >= 0 && x2 < psd->xres);

        assert (x2 >= x1);

        assert (y >= 0 && y < psd->yres);

        assert (c < psd->ncolors);

        DRAWON;

        set_color (c);

        set_op(mode_table[gr_mode]);

        /*

        * The following fast drawhline code is buggy for XOR drawing,

        * for some reason.  So, we use the equivalent slower drawpixel

        * method when not drawing MWMODE_COPY.

        */

        if(gr_mode == MWMODE_COPY) {

#if _MINIX

                dst = (unsigned char *)(SCREENBASE + (x1>>3) + y*BYTESPERLINE);

#else

                dst = SCREENBASE + (x1>>3) + y * BYTESPERLINE;

#endif

                if ((x1>>3) == (x2>>3)) {

                        select_and_set_mask ((0xff >> (x1 & 7)) & (0xff << (7 - (x2 & 7))));

                        RMW_FP (dst);

                } else {

                        select_and_set_mask (0xff >> (x1 & 7));

                        RMW_FP (dst++);

                        set_mask (0xff);

#if _MINIX

                        last = (unsigned char *)(SCREENBASE + (x2>>3) + y * BYTESPERLINE);

#else

                        last = SCREENBASE + (x2>>3) + y * BYTESPERLINE;

#endif

                        while (dst < last)

                                PUTBYTE_FP(dst++, 1);

                        set_mask (0xff << (7 - (x2 & 7)));

                        RMW_FP (dst);

                }

        } else {

                /* slower method, draw pixel by pixel*/

                select_mask ();

                while(x1 <= x2) {

                        set_mask (mask[x1&7]);

                        RMW_FP ((FARADDR)SCREENBASE + (x1++>>3) + y * BYTESPERLINE);

                }

        }

        DRAWOFF;

}

/* Draw a vertical line from x,y1 to x,y2 including final point*/

void

ega_drawvertline(PSD psd,unsigned int x, unsigned int y1, unsigned int y2,

        MWPIXELVAL c)

{

        FARADDR dst, last;

        assert (x >= 0 && x < psd->xres);

        assert (y1 >= 0 && y1 < psd->yres);

        assert (y2 >= 0 && y2 < psd->yres);

        assert (y2 >= y1);

        assert (c < psd->ncolors);

        DRAWON;

        set_op(mode_table[gr_mode]);

        set_color (c);

        select_and_set_mask (mask[x&7]);

#if _MINIX

        dst = (unsigned char *)(SCREENBASE + (x>>3) + y1 * BYTESPERLINE);

        last = (unsigned char *)(SCREENBASE + (x>>3) + y2 * BYTESPERLINE);

#else

        dst = SCREENBASE + (x>>3) + y1 * BYTESPERLINE;

        last = SCREENBASE + (x>>3) + y2 * BYTESPERLINE;

#endif

        while (dst <= last) {

                RMW_FP (dst);

                dst += BYTESPERLINE;

        }

        DRAWOFF;

}

#if FBVGA

SUBDRIVER vgaplan4 = {

        (void *)ega_init,

        (void *)ega_drawpixel,

        (void *)ega_readpixel,

        (void *)ega_drawhorzline,

        (void *)ega_drawvertline,

        (void *)gen_fillrect,

        (void *)ega_blit

};

#endif /* FBVGA*/