/* Copyright (C) 1991, 1995, 1996, 1997, 1998, 1999 artofcode LLC.  All rights reserved.
  
  This program is free software; you can redistribute it and/or modify it
  under the terms of the GNU General Public License as published by the
  Free Software Foundation; either version 2 of the License, or (at your
  option) any later version.

  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.

  You should have received a copy of the GNU General Public License along
  with this program; if not, write to the Free Software Foundation, Inc.,
  59 Temple Place, Suite 330, Boston, MA, 02111-1307.

*/

/*$Id: gdevsvga.c,v 1.2.6.1.2.1 2003/01/17 00:49:01 giles Exp $ */
/* SuperVGA display drivers */
#include "memory_.h"
#include "gconfigv.h"		/* for USE_ASM */
#include "gx.h"
#include "gserrors.h"
#include "gxarith.h"		/* for ...log2 */
#include "gxdevice.h"
#include "gdevpccm.h"
#include "gdevpcfb.h"
#include "gdevsvga.h"
#include "gsparam.h"

/* The color map for dynamically assignable colors. */
#define first_dc_index 64
private int next_dc_index;

#define dc_hash_size 293	/* prime, >num_dc */
typedef struct {
    ushort rgb, index;
} dc_entry;
private dc_entry dynamic_colors[dc_hash_size + 1];

#define num_colors 255

/* Macro for casting gx_device argument */
#define fb_dev ((gx_device_svga *)dev)

/* Procedure records */
#define svga_procs(open) {\
	open, NULL /*get_initial_matrix*/,\
	NULL /*sync_output*/, NULL /*output_page*/, svga_close,\
	svga_map_rgb_color, svga_map_color_rgb,\
	svga_fill_rectangle, NULL /*tile_rectangle*/,\
	svga_copy_mono, svga_copy_color, NULL /*draw_line*/,\
	svga_get_bits, NULL /*get_params*/, svga_put_params,\
	NULL /*map_cmyk_color*/, NULL /*get_xfont_procs*/,\
	NULL /*get_xfont_device*/, NULL /*map_rgb_alpha_color*/,\
	gx_page_device_get_page_device, NULL /*get_alpha_bits*/,\
	svga_copy_alpha\
}

/* Save the controller mode */
private int svga_save_mode = -1;

/* ------ Internal routines ------ */

#define regen 0xa000

/* Construct a pointer for writing a pixel. */
/* Assume 64K pages, 64K granularity. */
/* We know that y is within bounds. */
#define set_pixel_ptr(ptr, fbdev, x, y, wnum)\
{	ulong index = (ulong)(y) * fbdev->raster + (uint)(x);\
	if ( (uint)(index >> 16) != fbdev->current_page )\
	   {	(*fbdev->set_page)(fbdev, (fbdev->current_page = index >> 16), wnum);\
	   }\
	ptr = (fb_ptr)MK_PTR(regen, (ushort)index);\
}
#define set_pixel_write_ptr(ptr, fbdev, x, y)\
  set_pixel_ptr(ptr, fbdev, x, y, fbdev->wnum_write)
#define set_pixel_read_ptr(ptr, fbdev, x, y)\
  set_pixel_ptr(ptr, fbdev, x, y, fbdev->wnum_read)

/* Find the graphics mode for a desired width and height. */
/* Set the mode in the device structure and return 0, */
/* or return an error code. */
int
svga_find_mode(gx_device * dev, const mode_info * mip)
{
    for (;; mip++) {
	if (mip->width >= fb_dev->width &&
	    mip->height >= fb_dev->height ||
	    mip[1].mode < 0
	    ) {
	    fb_dev->mode = mip;
	    gx_device_adjust_resolution(dev, mip->width, mip->height, 1);
	    fb_dev->raster = fb_dev->width;
	    return 0;
	}
    }
    return_error(gs_error_rangecheck);
}

/* Set the index for writing into the color DAC. */
#define svga_dac_set_write_index(i) outportb(0x3c8, i)

/* Write 6-bit R,G,B values into the color DAC. */
#define svga_dac_write(r, g, b)\
  (outportb(0x3c9, r), outportb(0x3c9, g), outportb(0x3c9, b))

/* ------ Common procedures ------ */

#define cv_bits(v,n) (v >> (gx_color_value_bits - n))

/* Initialize the dynamic color table, if any. */
void
svga_init_colors(gx_device * dev)
{
    if (fb_dev->fixed_colors)
	next_dc_index = num_colors;
    else {
	memset(dynamic_colors, 0,
	       (dc_hash_size + 1) * sizeof(dc_entry));
	next_dc_index = first_dc_index;
    }
}

/* Load the color DAC with the predefined colors. */
private void
svga_load_colors(gx_device * dev)
{
    int ci;

    svga_dac_set_write_index(0);
    if (fb_dev->fixed_colors)
	for (ci = 0; ci < num_colors; ci++) {
	    gx_color_value rgb[3];

	    pc_8bit_map_color_rgb(dev, (gx_color_index) ci, rgb);
	    svga_dac_write(cv_bits(rgb[0], 6), cv_bits(rgb[1], 6),
			   cv_bits(rgb[2], 6));
    } else
	for (ci = 0; ci < 64; ci++) {
	    static const byte c2[10] =
	    {0, 42, 0, 0, 0, 0, 0, 0, 21, 63};

	    svga_dac_write(c2[(ci >> 2) & 9], c2[(ci >> 1) & 9],
			   c2[ci & 9]);
	}
}

/* Initialize the device structure and the DACs. */
int
svga_open(gx_device * dev)
{
    fb_dev->x_pixels_per_inch =
	fb_dev->y_pixels_per_inch =
	fb_dev->height / PAGE_HEIGHT_INCHES;
    /* Set the display mode. */
    if (svga_save_mode < 0)
	svga_save_mode = (*fb_dev->get_mode) ();
    (*fb_dev->set_mode) (fb_dev->mode->mode);
    svga_init_colors(dev);
    svga_load_colors(dev);
    fb_dev->current_page = -1;
    return 0;
}

/* Close the device; reinitialize the display for text mode. */
int
svga_close(gx_device * dev)
{
    if (svga_save_mode >= 0)
	(*fb_dev->set_mode) (svga_save_mode);
    svga_save_mode = -1;
    return 0;
}

/* Map a r-g-b color to a palette index. */
/* The first 64 entries of the color map are set */
/* for compatibility with the older display modes: */
/* these are indexed as 0.0.R0.G0.B0.R1.G1.B1. */
gx_color_index
svga_map_rgb_color(gx_device * dev, gx_color_value r, gx_color_value g,
		   gx_color_value b)
{
    ushort rgb;

    if (fb_dev->fixed_colors) {
	gx_color_index ci = pc_8bit_map_rgb_color(dev, r, g, b);

	/* Here is where we should permute the index to match */
	/* the old color map... but we don't yet. */
	return ci;
    } {
	ushort r5 = cv_bits(r, 5), g5 = cv_bits(g, 5), b5 = cv_bits(b, 5);
	static const byte cube_bits[32] =
	{0, 128, 128, 128, 128, 128, 128, 128, 128, 128,
	 8, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128,
	 1, 128, 128, 128, 128, 128, 128, 128, 128, 128,
	 9
	};
	uint cx = ((uint) cube_bits[r5] << 2) +
	((uint) cube_bits[g5] << 1) +
	(uint) cube_bits[b5];

	/* Check for a color on the cube. */
	if (cx < 64)
	    return (gx_color_index) cx;
	/* Not on the cube, check the dynamic color table. */
	rgb = (r5 << 10) + (g5 << 5) + b5;
    }
    {
	register dc_entry *pdc;

	for (pdc = &dynamic_colors[rgb % dc_hash_size];
	     pdc->rgb != 0; pdc++
	    )
	    if (pdc->rgb == rgb)
		return (gx_color_index) (pdc->index);
	if (pdc == &dynamic_colors[dc_hash_size]) {	/* Wraparound */
	    for (pdc = &dynamic_colors[0]; pdc->rgb != 0; pdc++)
		if (pdc->rgb == rgb)
		    return (gx_color_index) (pdc->index);
	}
	if (next_dc_index == num_colors) {	/* No space left, report failure. */
	    return gx_no_color_index;
	}
	/* Not on the cube, and not in the dynamic table. */
	/* Put in the dynamic table if space available. */
	{
	    int i = next_dc_index++;

	    pdc->rgb = rgb;
	    pdc->index = i;
	    svga_dac_set_write_index(i);
	    svga_dac_write(cv_bits(r, 6), cv_bits(g, 6),
			   cv_bits(b, 6));
	    return (gx_color_index) i;
	}
    }
}

/* Map a color code to r-g-b. */
/* This routine must invert the transformation of the one above. */
/* Since this is practically never used, we just read the DAC. */
int
svga_map_color_rgb(gx_device * dev, gx_color_index color,
		   gx_color_value prgb[3])
{
    uint cval;

    outportb(0x3c7, (byte) color);
#define dacin() (cval = inportb(0x3c9) >> 1,\
  ((cval << 11) + (cval << 6) + (cval << 1) + (cval >> 4)) >>\
   (16 - gx_color_value_bits))
    prgb[0] = dacin();
    prgb[1] = dacin();
    prgb[2] = dacin();
#undef dacin
    return 0;
}

/* Fill a rectangle. */
int
svga_fill_rectangle(gx_device * dev, int x, int y, int w, int h,
		    gx_color_index color)
{
    uint raster = fb_dev->raster;
    ushort limit = (ushort) - raster;
    int yi;
    fb_ptr ptr;

    fit_fill(dev, x, y, w, h);
    set_pixel_write_ptr(ptr, fb_dev, x, y);
    /* Most fills are very small and don't cross a page boundary. */
    yi = h;
    switch (w) {
	case 0:
	    return 0;		/* no-op */
	case 1:
	    while (--yi >= 0 && PTR_OFF(ptr) < limit)
		ptr[0] = (byte) color,
		    ptr += raster;
	    if (!++yi)
		return 0;
	    break;
	case 2:
	    while (--yi >= 0 && PTR_OFF(ptr) < limit)
		ptr[0] = ptr[1] = (byte) color,
		    ptr += raster;
	    if (!++yi)
		return 0;
	    break;
	case 3:
	    while (--yi >= 0 && PTR_OFF(ptr) < limit)
		ptr[0] = ptr[1] = ptr[2] = (byte) color,
		    ptr += raster;
	    if (!++yi)
		return 0;
	    break;
	case 4:
	    while (--yi >= 0 && PTR_OFF(ptr) < limit)
		ptr[0] = ptr[1] = ptr[2] = ptr[3] = (byte) color,
		    ptr += raster;
	    if (!++yi)
		return 0;
	    break;
	default:
	    if (w < 0)
		return 0;
	    /* Check for erasepage. */
	    if (w == dev->width && h == dev->height &&
		color < first_dc_index
		)
		svga_init_colors(dev);
    }
    while (--yi >= 0) {
	if (PTR_OFF(ptr) < limit) {
	    memset(ptr, (byte) color, w);
	    ptr += raster;
	} else if (PTR_OFF(ptr) <= (ushort) (-w)) {
	    memset(ptr, (byte) color, w);
	    if (yi > 0)
		set_pixel_write_ptr(ptr, fb_dev, x, y + h - yi);
	} else {
	    uint left = (uint) 0x10000 - PTR_OFF(ptr);

	    memset(ptr, (byte) color, left);
	    set_pixel_write_ptr(ptr, fb_dev, x + left, y + h - 1 - yi);
	    memset(ptr, (byte) color, w - left);
	    ptr += raster - left;
	}
    }
    return 0;
}

/* Copy a monochrome bitmap.  The colors are given explicitly. */
/* Color = gx_no_color_index means transparent (no effect on the image). */
int
svga_copy_mono(gx_device * dev,
	       const byte * base, int sourcex, int sraster, gx_bitmap_id id,
      int x, int y, int w, int h, gx_color_index czero, gx_color_index cone)
{
    uint raster = fb_dev->raster;
    ushort limit;
    register int wi;
    uint skip;
    int yi;
    register fb_ptr ptr = (fb_ptr) 0;
    const byte *srow;
    uint invert;

    fit_copy(dev, base, sourcex, sraster, id, x, y, w, h);
    limit = (ushort) - w;
    skip = raster - w + 1;
    srow = base + (sourcex >> 3);
#define izero (int)czero
#define ione (int)cone
    if (ione == no_color) {
	gx_color_index temp;

	if (izero == no_color)
	    return 0;		/* no-op */
	temp = czero;
	czero = cone;
	cone = temp;
	invert = ~0;
    } else
	invert = 0;
    /* Pre-filling saves us a test in the loop, */
    /* and since tiling is uncommon, we come out ahead. */
    if (izero != no_color)
	svga_fill_rectangle(dev, x, y, w, h, czero);
    for (yi = 0; yi < h; yi++) {
	const byte *sptr = srow;
	uint bits;
	int bitno = sourcex & 7;

	wi = w;
	if (PTR_OFF(ptr) <= skip) {
	    set_pixel_write_ptr(ptr, fb_dev, x, y + yi);
	} else if (PTR_OFF(ptr) > limit) {	/* We're crossing a page boundary. */
	    /* This is extremely rare, so it doesn't matter */
	    /* how slow it is. */
	    int xi = (ushort) - PTR_OFF(ptr);

	    svga_copy_mono(dev, srow, sourcex & 7, sraster,
			   gx_no_bitmap_id, x, y + yi, xi, 1,
			   gx_no_color_index, cone);
	    set_pixel_write_ptr(ptr, fb_dev, x + xi, y + yi);
	    sptr = srow - (sourcex >> 3) + ((sourcex + xi) >> 3);
	    bitno = (sourcex + xi) & 7;
	    wi -= xi;
	}
	bits = *sptr ^ invert;
	switch (bitno) {
#define ifbit(msk)\
  if ( bits & msk ) *ptr = (byte)ione;\
  if ( !--wi ) break; ptr++
	    case 0:
	      bit0:ifbit(0x80);
	    case 1:
		ifbit(0x40);
	    case 2:
		ifbit(0x20);
	    case 3:
		ifbit(0x10);
	    case 4:
		ifbit(0x08);
	    case 5:
		ifbit(0x04);
	    case 6:
		ifbit(0x02);
	    case 7:
		ifbit(0x01);
#undef ifbit
		bits = *++sptr ^ invert;
		goto bit0;
	}
	ptr += skip;
	srow += sraster;
    }
#undef izero
#undef ione
    return 0;
}

/* Copy a color pixelmap.  This is just like a bitmap, */
/* except that each pixel takes 8 bits instead of 1. */
int
svga_copy_color(gx_device * dev,
		const byte * base, int sourcex, int sraster, gx_bitmap_id id,
		int x, int y, int w, int h)
{
    int xi, yi;
    int skip;
    const byte *sptr;
    fb_ptr ptr;

    fit_copy(dev, base, sourcex, sraster, id, x, y, w, h);
    skip = sraster - w;
    sptr = base + sourcex;
    for (yi = y; yi - y < h; yi++) {
	ptr = 0;
	for (xi = x; xi - x < w; xi++) {
	    if (PTR_OFF(ptr) == 0)
		set_pixel_write_ptr(ptr, fb_dev, xi, yi);
	    *ptr++ = *sptr++;
	}
	sptr += skip;
    }
    return 0;
}

/* Put parameters. */
int
svga_put_params(gx_device * dev, gs_param_list * plist)
{
    int ecode = 0;
    int code;
    const char *param_name;

    if ((code = ecode) < 0 ||
	(code = gx_default_put_params(dev, plist)) < 0
	) {
    }
    return code;
}

/* Read scan lines back from the frame buffer. */
int
svga_get_bits(gx_device * dev, int y, byte * data, byte ** actual_data)
{
    uint bytes_per_row = dev->width;
    ushort limit = (ushort) - bytes_per_row;
    fb_ptr src;

    if (y < 0 || y >= dev->height)
	return gs_error_rangecheck;
    set_pixel_read_ptr(src, fb_dev, 0, y);
    /* The logic here is similar to fill_rectangle. */
    if (PTR_OFF(src) <= limit)
	memcpy(data, src, bytes_per_row);
    else {
	uint left = (uint) 0x10000 - PTR_OFF(src);

	memcpy(data, src, left);
	set_pixel_read_ptr(src, fb_dev, left, y);
	memcpy(data + left, src, bytes_per_row - left);
    }
    if (actual_data != 0)
	*actual_data = data;
    return 0;
}

/* Copy an alpha-map to the screen. */
/* Depth is 1, 2, or 4. */
private int
svga_copy_alpha(gx_device * dev, const byte * base, int sourcex,
		int sraster, gx_bitmap_id id, int x, int y, int w, int h,
		gx_color_index color, int depth)
{
    int xi, yi;
    int skip;
    const byte *sptr;
    byte mask;
    int ishift;

    /* We fake alpha by interpreting it as saturation, i.e., */
    /* alpha = 0 is white, alpha = 1 is the full color. */
    byte shades[16];
    gx_color_value rgb[3];
    int log2_depth = depth >> 1;	/* works for 1,2,4 */
    int n1 = (1 << depth) - 1;

    fit_copy(dev, base, sourcex, sraster, id, x, y, w, h);
    shades[0] = (byte) svga_map_rgb_color(dev, gx_max_color_value,
					  gx_max_color_value,
					  gx_max_color_value);
    shades[n1] = (byte) color;
    if (n1 > 1) {
	memset(shades + 1, 255, n1 - 1);
	svga_map_color_rgb(dev, color, rgb);
    }
    skip = sraster - ((w * depth) >> 3);
    sptr = base + (sourcex >> (3 - log2_depth));
    mask = n1;
    ishift = (~sourcex & (7 >> log2_depth)) << log2_depth;
    for (yi = y; yi - y < h; yi++) {
	fb_ptr ptr = 0;
	int shift = ishift;

	for (xi = x; xi - x < w; xi++, ptr++) {
	    uint a = (*sptr >> shift) & mask;

	    if (PTR_OFF(ptr) == 0)
		set_pixel_write_ptr(ptr, fb_dev, xi, yi);
	  map:if (a != 0) {
		byte ci = shades[a];

		if (ci == 255) {	/* Map the color now. */
#define make_shade(v, alpha, n1)\
  (gx_max_color_value -\
   ((ulong)(gx_max_color_value - (v)) * (alpha) / (n1)))
		    gx_color_value r =
		    make_shade(rgb[0], a, n1);
		    gx_color_value g =
		    make_shade(rgb[1], a, n1);
		    gx_color_value b =
		    make_shade(rgb[2], a, n1);
		    gx_color_index sci =
		    svga_map_rgb_color(dev, r, g, b);

		    if (sci == gx_no_color_index) {
			a += (n1 + 1 - a) >> 1;
			goto map;
		    }
		    shades[a] = ci = (byte) sci;
		}
		*ptr = ci;
	    }
	    if (shift == 0)
		shift = 8 - depth, sptr++;
	    else
		shift -= depth;
	}
	sptr += skip;
    }
    return 0;
}

/* ------ The VESA device ------ */

private dev_proc_open_device(vesa_open);
private const gx_device_procs vesa_procs = svga_procs(vesa_open);
int vesa_get_mode(P0());
void vesa_set_mode(P1(int));
private void vesa_set_page(P3(gx_device_svga *, int, int));
gx_device_svga far_data gs_vesa_device =
svga_device(vesa_procs, "vesa", vesa_get_mode, vesa_set_mode, vesa_set_page);

/* Define the structures for information returned by the BIOS. */
#define bits_include(a, m) !(~(a) & (m))
/* Information about the BIOS capabilities. */
typedef struct {
    byte vesa_signature[4];	/* "VESA" */
    ushort vesa_version;
    char *product_info;		/* product name string */
    byte capabilities[4];	/* (undefined) */
    ushort *mode_list;		/* supported video modes, -1 ends */
} vga_bios_info;

/* Information about an individual VESA mode. */
typedef enum {
    m_supported = 1,
    m_graphics = 0x10
} mode_attribute;
typedef enum {
    w_supported = 1,
    w_readable = 2,
    w_writable = 4
} win_attribute;
typedef struct {
    ushort mode_attributes;
    byte win_a_attributes;
    byte win_b_attributes;
    ushort win_granularity;
    ushort win_size;
    ushort win_a_segment;
    ushort win_b_segment;
    void (*win_func_ptr) (P2(int, int));
    ushort bytes_per_line;
    /* Optional information */
    ushort x_resolution;
    ushort y_resolution;
    byte x_char_size;
    byte y_char_size;
    byte number_of_planes;
    byte bits_per_pixel;
    byte number_of_banks;
    byte memory_model;
    byte bank_size;
    /* Padding to 256 bytes */
    byte _padding[256 - 29];
} vesa_info;

/* Read the device mode */
int
vesa_get_mode(void)
{
    registers regs;

    regs.h.ah = 0x4f;
    regs.h.al = 0x03;
    int86(0x10, &regs, &regs);
    return regs.rshort.bx;
}

/* Set the device mode */
void
vesa_set_mode(int mode)
{
    registers regs;

    regs.h.ah = 0x4f;
    regs.h.al = 0x02;
    regs.rshort.bx = mode;
    int86(0x10, &regs, &regs);
}

/* Read information about a device mode */
private int
vesa_get_info(int mode, vesa_info _ss * info)
{
    registers regs;
    struct SREGS sregs;

    regs.h.ah = 0x4f;
    regs.h.al = 0x01;
    regs.rshort.cx = mode;
    segread(&sregs);
    sregs.es = sregs.ss;
    regs.rshort.di = PTR_OFF(info);
    int86x(0x10, &regs, &regs, &sregs);
#ifdef DEBUG
    if (regs.h.ah == 0 && regs.h.al == 0x4f)
	dlprintf8("vesa_get_info(%x): ma=%x wa=%x/%x wg=%x ws=%x wseg=%x/%x\n",
		  mode, info->mode_attributes,
		  info->win_a_attributes, info->win_b_attributes,
		  info->win_granularity, info->win_size,
		  info->win_a_segment, info->win_b_segment);
    else
	dlprintf3("vesa_get_info(%x) failed: ah=%x al=%x\n",
		  mode, regs.h.ah, regs.h.al);
#endif
    return (regs.h.ah == 0 && regs.h.al == 0x4f ? 0 : -1);
}

/* Initialize the graphics mode. */
/* Shared routine to look up a VESA-compatible BIOS mode. */
private int
vesa_find_mode(gx_device * dev, const mode_info * mode_table)
{				/* Select the proper video mode */
    vesa_info info;
    const mode_info *mip;

    for (mip = mode_table; mip->mode >= 0; mip++) {
	if (mip->width >= fb_dev->width &&
	    mip->height >= fb_dev->height &&
	    vesa_get_info(mip->mode, &info) >= 0 &&
	    bits_include(info.mode_attributes,
			 m_supported | m_graphics) &&
	    info.win_granularity <= 64 &&
	    (info.win_granularity & (info.win_granularity - 1)) == 0 &&
	    info.win_size == 64 &&
	    bits_include(info.win_a_attributes,
			 w_supported) &&
	    info.win_a_segment == regen
	    ) {			/* Make sure we can both read & write. */
	    /* Initialize for the default case. */
	    fb_dev->wnum_read = 0;
	    fb_dev->wnum_write = 0;
	    if (bits_include(info.win_a_attributes,
			     w_readable | w_writable)
		)
		break;
	    else if (info.win_b_segment == regen &&
		     bits_include(info.win_b_attributes,
				  w_supported) &&
		     bits_include(info.win_a_attributes |
				  info.win_b_attributes,
				  w_readable | w_writable)
		) {		/* Two superimposed windows. */
		if (!bits_include(info.win_a_attributes,
				  w_writable)
		    )
		    fb_dev->wnum_write = 1;
		else
		    fb_dev->wnum_read = 1;
	    }
	    break;
	}
    }
    if (mip->mode < 0)
	return_error(gs_error_rangecheck);	/* mode not available */
    fb_dev->mode = mip;
    gx_device_adjust_resolution(dev, mip->width, mip->height, 1);
    fb_dev->info.vesa.bios_set_page = info.win_func_ptr;
    fb_dev->info.vesa.pn_shift = ilog2(64 / info.win_granularity);
    /* Reset the raster per the VESA info. */
    fb_dev->raster = info.bytes_per_line;
    return 0;
}
private int
vesa_open(gx_device * dev)
{
    static const mode_info mode_table[] =
    {
	{640, 400, 0x100},
	{640, 480, 0x101},
	{800, 600, 0x103},
	{1024, 768, 0x105},
	{1280, 1024, 0x107},
	{-1, -1, -1}
    };
    int code = vesa_find_mode(dev, mode_table);

    if (code < 0)
	return code;
    return svga_open(dev);
}

/* Set the current display page. */
private void
vesa_set_page(gx_device_svga * dev, int pn, int wnum)
{
#if USE_ASM
    extern void vesa_call_set_page(P3(void (*)(P2(int, int)), int, int));

    if (dev->info.vesa.bios_set_page != NULL)
	vesa_call_set_page(dev->info.vesa.bios_set_page, pn << dev->info.vesa.pn_shift, wnum);
    else
#endif
    {
	registers regs;

	regs.rshort.dx = pn << dev->info.vesa.pn_shift;
	regs.h.ah = 0x4f;
	regs.h.al = 5;
	regs.rshort.bx = wnum;
	int86(0x10, &regs, &regs);
    }
}

/* ------ The ATI Wonder device ------ */

private dev_proc_open_device(atiw_open);
private const gx_device_procs atiw_procs = svga_procs(atiw_open);
private int atiw_get_mode(P0());
private void atiw_set_mode(P1(int));
private void atiw_set_page(P3(gx_device_svga *, int, int));
gx_device_svga far_data gs_atiw_device =
svga_device(atiw_procs, "atiw", atiw_get_mode, atiw_set_mode, atiw_set_page);

/* Read the device mode */
private int
atiw_get_mode(void)
{
    registers regs;

    regs.h.ah = 0xf;
    int86(0x10, &regs, &regs);
    return regs.h.al;
}

/* Set the device mode */
private void
atiw_set_mode(int mode)
{
    registers regs;

    regs.h.ah = 0;
    regs.h.al = mode;
    int86(0x10, &regs, &regs);
}

/* Initialize the graphics mode. */
private int
atiw_open(gx_device * dev)
{				/* Select the proper video mode */
    {
	static const mode_info mode_table[] =
	{
	    {640, 400, 0x61},
	    {640, 480, 0x62},
	    {800, 600, 0x63},
	    {1024, 768, 0x64},
	    {-1, -1, -1}
	};
	int code = svga_find_mode(dev, mode_table);

	if (code < 0)
	    return code;	/* mode not available */
	fb_dev->info.atiw.select_reg = *(int *)MK_PTR(0xc000, 0x10);
	return svga_open(dev);
    }
}

/* Set the current display page. */
private void
atiw_set_page(gx_device_svga * dev, int pn, int wnum)
{
    int select_reg = dev->info.atiw.select_reg;
    byte reg;

    disable();
    outportb(select_reg, 0xb2);
    reg = inportb(select_reg + 1);
    outportb(select_reg, 0xb2);
    outportb(select_reg + 1, (reg & 0xe1) + (pn << 1));
    enable();
}

/* ------ The Trident device ------ */

private dev_proc_open_device(tvga_open);
private const gx_device_procs tvga_procs = svga_procs(tvga_open);

/* We can use the atiw_get/set_mode procedures. */
private void tvga_set_page(P3(gx_device_svga *, int, int));
gx_device_svga far_data gs_tvga_device =
svga_device(tvga_procs, "tvga", atiw_get_mode, atiw_set_mode, tvga_set_page);

/* Initialize the graphics mode. */
private int
tvga_open(gx_device * dev)
{
    fb_dev->wnum_read = 1;
    fb_dev->wnum_write = 0;
    /* Select the proper video mode */
    {
	static const mode_info mode_table[] =
	{
	    {640, 400, 0x5c},
	    {640, 480, 0x5d},
	    {800, 600, 0x5e},
	    {1024, 768, 0x62},
	    {-1, -1, -1}
	};
	int code = svga_find_mode(dev, mode_table);

	if (code < 0)
	    return code;	/* mode not available */
	return svga_open(dev);
    }
}

/* Set the current display page. */
private void
tvga_set_page(gx_device_svga * dev, int pn, int wnum)
{
    /* new mode */
    outportb(0x3c4, 0x0b);
    inportb(0x3c4);

    outportb(0x3c4, 0x0e);
    outportb(0x3c5, pn ^ 2);
}

/* ------ The Tseng Labs ET3000/4000 devices ------ */

private dev_proc_open_device(tseng_open);
private const gx_device_procs tseng_procs =
svga_procs(tseng_open);

/* We can use the atiw_get/set_mode procedures. */
private void tseng_set_page(P3(gx_device_svga *, int, int));

/* The 256-color Tseng device */
gx_device_svga far_data gs_tseng_device =
svga_device(tseng_procs, "tseng", atiw_get_mode, atiw_set_mode, tseng_set_page);

/* Initialize the graphics mode. */
private int
tseng_open(gx_device * dev)
{
    fb_dev->wnum_read = 1;
    fb_dev->wnum_write = 0;
    /* Select the proper video mode */
    {
	static const mode_info mode_table[] =
	{
	    {640, 350, 0x2d},
	    {640, 480, 0x2e},
	    {800, 600, 0x30},
	    {1024, 768, 0x38},
	    {-1, -1, -1}
	};
	int code = svga_find_mode(dev, mode_table);
	volatile_fb_ptr p0 = (volatile_fb_ptr) MK_PTR(regen, 0);

	if (code < 0)
	    return code;	/* mode not available */
	code = svga_open(dev);
	if (code < 0)
	    return 0;
	/* Figure out whether we have an ET3000 or an ET4000 */
	/* by playing with the segment register. */
	outportb(0x3cd, 0x44);
	*p0 = 4;		/* byte 0, page 4 */
	outportb(0x3cd, 0x40);
	*p0 = 3;		/* byte 0, page 0 */
	fb_dev->info.tseng.et_model = *p0;
	/* read page 0 if ET3000, */
	/* page 4 if ET4000 */
	return 0;
    }
}

/* Set the current display page. */
private void
tseng_set_page(gx_device_svga * dev, int pn, int wnum)
{				/* The ET3000 has read page = 5:3, write page = 2:0; */
    /* the ET4000 has read page = 7:4, write page = 3:0. */
    int shift = dev->info.tseng.et_model;
    int mask = (1 << shift) - 1;

    if (wnum)
	pn <<= shift, mask <<= shift;
    outportb(0x3cd, (inportb(0x3cd) & ~mask) + pn);
}
/* ------ The Cirrus device (CL-GD54XX) ------ */
/* Written by Piotr Strzelczyk, BOP s.c., Gda\'nsk, Poland, */
/* e-mail contact via B.Jackowski@GUST.org.pl */

private dev_proc_open_device(cirr_open);
private gx_device_procs cirr_procs = svga_procs(cirr_open);

/* We can use the atiw_get/set_mode procedures. */
private void cirr_set_page(P3(gx_device_svga *, int, int));
gx_device_svga gs_cirr_device =
svga_device(cirr_procs, "cirr", atiw_get_mode, atiw_set_mode, cirr_set_page);

/* Initialize the graphics mode. */
private int
cirr_open(gx_device * dev)
{
    fb_dev->wnum_read = 1;
    fb_dev->wnum_write = 0;
    /* Select the proper video mode */
    {
	static const mode_info mode_table[] =
	{
	    {640, 400, 0x5e},
	    {640, 480, 0x5f},
	    {800, 600, 0x5c},
	    {1024, 768, 0x60},
	    {-1, -1, -1}
	};
	int code = svga_find_mode(dev, mode_table);

	if (code < 0)
	    return code;	/* mode not available */
	outportb(0x3c4, 0x06);
	outportb(0x3c5, 0x12);
	outportb(0x3ce, 0x0b);
	outportb(0x3cf, (inportb(0x3cf) & 0xde));
	return svga_open(dev);
    }
}

/* Set the current display page. */
private void
cirr_set_page(gx_device_svga * dev, int pn, int wnum)
{
    outportb(0x3ce, 0x09);
    outportb(0x3cf, pn << 4);
}

/* ------ The Avance Logic device (mostly experimental) ------ */
/* For questions about this device, please contact Stefan Freund */
/* <freund@ikp.uni-koeln.de>. */

private dev_proc_open_device(ali_open);
private const gx_device_procs ali_procs = svga_procs(ali_open);

/* We can use the atiw_get/set_mode procedures. */
private void ali_set_page(P3(gx_device_svga *, int, int));

/* The 256-color Avance Logic device */
gx_device_svga gs_ali_device =
svga_device(ali_procs, "ali", atiw_get_mode, atiw_set_mode,
	    ali_set_page);

/* Initialize the graphics mode. */
private int
ali_open(gx_device * dev)
{
    fb_dev->wnum_read = 1;
    fb_dev->wnum_write = 0;
    /* Select the proper video mode */
    {
	static const mode_info mode_table[] =
	{
	    {640, 400, 0x29},
	    {640, 480, 0x2a},
	    {800, 600, 0x2c},
	    {1024, 768, 0x31},
	    {-1, -1, -1}
	};
	int code = svga_find_mode(dev, mode_table);

	if (code < 0)
	    return code;	/* mode not available */
	return svga_open(dev);
    }

}

/* Set the current display page. */
private void
ali_set_page(gx_device_svga * dev, int pn, int wnum)
{
    outportb(0x3d6, pn);	/* read  */
    outportb(0x3d7, pn);	/* write */
}