/* Copyright (C) 1990, 1991, 1993 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: gdevherc.c,v 1.2.6.1.2.1 2003/01/17 00:49:00 giles Exp $*/
/* IBM PC-compatible Hercules Graphics display driver */
/* using direct access to frame buffer */

#define FB_RASTER 90
#define SCREEN_HEIGHT 350
#define SCREEN_ASPECT_RATIO (54.0/35.0)
#define VIDEO_MODE 0x07
#define regen 0xb0000000L

#define interrupt			/* patch ANSI incompatibility */
#include "dos_.h"
typedef union REGS registers;
#include "gx.h"
#include "gsmatrix.h"			/* for gxdevice.h */
#include "gxbitmap.h"
#include "gxdevice.h"

/* outportb is defined in dos_.h */
#define outport2(port, index, data)\
  (outportb(port, index), outportb((port)+1, data))
/* Define the nominal page height in inches. */
#ifdef A4
#  define PAGE_HEIGHT_INCHES 11.69
#else
#  define PAGE_HEIGHT_INCHES 11.0
#endif

/* Dimensions of screen */
#define screen_size_x (FB_RASTER * 8)
#define screen_size_y SCREEN_HEIGHT
/* Other display parameters */
#define raster_x FB_RASTER
#define aspect_ratio SCREEN_ASPECT_RATIO
#define graphics_video_mode VIDEO_MODE

/* Procedures */

	/* See gxdevice.h for the definitions of the procedures. */

dev_proc_open_device(herc_open);
dev_proc_close_device(herc_close);
dev_proc_fill_rectangle(herc_fill_rectangle);
dev_proc_copy_mono(herc_copy_mono);
dev_proc_copy_color(herc_copy_color);

/* The device descriptor */
private gx_device_procs herc_procs = {
	herc_open,
	gx_default_get_initial_matrix,
	gx_default_sync_output,
	gx_default_output_page,
	herc_close,
	gx_default_map_rgb_color,
	gx_default_map_color_rgb,
	herc_fill_rectangle,
	gx_default_tile_rectangle,
	herc_copy_mono,
	herc_copy_color
};

gx_device far_data gs_herc_device = {
	std_device_std_body(gx_device, &herc_procs, "herc",
	  screen_size_x, screen_size_y,
	/* The following parameters map an appropriate fraction of */
	/* the screen to a full-page coordinate space. */
	/* This may or may not be what is desired! */
	  (screen_size_y * aspect_ratio) / PAGE_HEIGHT_INCHES,	/* x dpi */
	  screen_size_y / PAGE_HEIGHT_INCHES		/* y dpi */
	)
};


/* Forward declarations */
private int herc_get_mode(P0());
private void herc_set_mode(P1(int));

/* Save the HERC mode */
private int herc_save_mode = -1;

/* Reinitialize the herc for text mode */
int
herc_close(gx_device *dev)
{	if ( herc_save_mode >= 0 ) herc_set_mode(herc_save_mode);
	return 0;
}

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

/* Read the device mode */
private int
herc_get_mode(void)
{	registers regs;
	regs.h.ah = 0xf;
	int86(0x10, &regs, &regs);
	return regs.h.al;
}

/* Set the device mode */
private void
herc_set_mode(int mode)
{	registers regs;
	regs.h.ah = 0;
	regs.h.al = mode;
	int86(0x10, &regs, &regs);
}


/****************************************************************/
/* Hercules graphics card functions				*/
/*								*/
/* -- Taken from Jan/Feb 1988 issue of Micro Cornucopia #39	*/
/*								*/
/* --rewritten for MSC 5.1 on 02/18/91 by Phillip Conrad	*/
/****************************************************************/


static const char paramg[12] = {0x35, 0x2d, 0x2e, 0x07, 0x5b, 0x02,
			      0x57, 0x57, 0x02, 0x03, 0x00, 0x00};
/* (Never used)
static const char paramt[12] = {0x61, 0x50, 0x52, 0x0f, 0x19, 0x06,
			      0x19, 0x19, 0x02, 0x0d, 0x0b, 0x0c};
*/

/* Type and macro for frame buffer pointers. */
/*** Intimately tied to the 80x86 (x<2) addressing architecture. ***/
typedef byte far *fb_ptr; 
#  define mk_fb_ptr(x, y)\
    (fb_ptr)((regen) + ((0x2000 * ((y) % 4) + (90 * ((y) >> 2))) + ((int)(x) >> 3)))


/* Structure for operation parameters. */
/* Note that this structure is known to assembly code. */
/* Not all parameters are used for every operation. */
typedef struct rop_params_s {
	fb_ptr dest;			/* pointer to frame buffer */
	int draster;			/* raster of frame buffer */
	const byte far *src;		/* pointer to source data */
	int sraster;			/* source raster */
	int width;			/* width in bytes */
	int height;			/* height in scan lines */
	int shift;			/* amount to right shift source */
	int invert;			/* 0 or -1 to invert source */
	int data;			/* data for fill */
	int x_pos;		/*>>added--2/24/91 */
	int y_pos;
} rop_params;

/* Define the device port and register numbers, and the regen map base */
#define seq_addr 0x3b4		/* changed for HERC card (6845 ports)*/
#define graph_mode 0x3b8
#define graph_stat 0x3ba
#define graph_config 0x3bf

#ifndef regen
#define regen 0xa0000000L
#endif


/* Initialize the display for Hercules graphics mode */
int
herc_open(gx_device *dev)
{	int i;
	if ( herc_save_mode < 0 ) herc_save_mode = herc_get_mode();
/*	herc_set_mode(graphics_video_mode);  */
	outportb(graph_config,3);
	for(i=0;i<sizeof(paramg);i++)
	{
		outport2(seq_addr,i,paramg[i]); 
		
	}
	outportb(graph_mode,0x0a);	/* set page 0 */
	for(i=0;i<0x3FFFL;i++)	/* clear the screen */
		{
		int far *loc = (int far *)( regen  +(2L*i));
		*loc = 0;
		}

	return 0;
}

/* Macro for testing bit-inclusion */
#define bit_included_in(x,y) !((x)&~(y))

/* Copy a monochrome bitmap.  The colors are given explicitly. */
/* Color = gx_no_color_index means transparent (no effect on the image). */
int
herc_copy_mono(gx_device *dev,
  const byte *base, int sourcex, int raster, gx_bitmap_id id,
  int x, int y, int w, int h, gx_color_index izero, gx_color_index ione)
{	rop_params params;
#define czero (int)izero
#define cone (int)ione
	int dleft, sleft, count;
	int invert, zmask, omask;
	byte mask, rmask;

	if ( cone == czero )		/* vacuous case */
		return herc_fill_rectangle(dev, x, y, w, h, izero);

	/* clip */
	fit_copy(dev, base, sourcex, raster, id, x, y, w, h);
	params.dest = mk_fb_ptr(x, y);
	params.draster = raster_x;
	params.src = base + (sourcex >> 3);
	params.sraster = raster;
	params.height = h;
	params.shift = (x - sourcex) & 7;
	params.y_pos = y;
	params.x_pos = x;
	params.width = w;

	if(czero > cone) params.invert = -1;

	/* Macros for writing partial bytes. */
	/* bits has already been inverted by xor'ing with invert. */

#define write_byte_masked(ptr, bits, mask)\
  *ptr = ((bits | ~mask | zmask) & (*ptr | (bits & mask & omask)))

#define write_byte(ptr, bits)\
  *ptr = ((bits | zmask) & (*ptr | (bits & omask)))

	invert = (czero == 1 || cone == 0 ? -1 : 0); 
/*	invert = (czero == 1 || cone == 1 ? -1 : 0); */
	zmask = (czero == 0 || cone == 0 ? 0 : -1);
	omask = (czero == 1 || cone == 1 ? -1 : 0);

#undef czero
#undef cone

	/* Actually copy the bits. */

	sleft = 8 - (sourcex & 7);
	dleft = 8 - (x & 7);
	mask = 0xff >> (8 - dleft);
	count = w;
	if ( w < dleft )
		mask -= mask >> w,
		rmask = 0;
	else
		rmask = 0xff00 >> ((w - dleft) & 7);

	if (sleft == dleft)		/* optimize the aligned case */
	{
		w -= dleft;
		while ( --h >= 0 )
		{
			register const byte *bptr = params.src;
			register byte *optr = mk_fb_ptr(params.x_pos,params.y_pos);
			register int bits = *bptr ^ invert;	/* first partial byte */

			count = w;
						
			write_byte_masked(optr, bits, mask);
			
			/* Do full bytes. */

			while ((count -= 8) >= 0)
			{
				bits = *++bptr ^ invert;
				params.x_pos += 8;
				optr = mk_fb_ptr(params.x_pos,params.y_pos);
				write_byte(optr, bits);
			}
			/* Do last byte */
			
			if (count > -8)
			{
				bits = *++bptr ^ invert;
				params.x_pos += 8;
				optr = mk_fb_ptr(params.x_pos,params.y_pos);
				write_byte_masked(optr, bits, rmask);
			}
/*			dest += BPL; */
			params.y_pos++;
			params.x_pos = x;
			params.src += raster;
		}
	}
	else
	{
		int skew = (sleft - dleft) & 7;
		int cskew = 8 - skew;
		
		while (--h >= 0)
		{
			const byte *bptr = params.src;
			byte *optr = mk_fb_ptr(params.x_pos,params.y_pos);
			register int bits;

			count = w;
						
			/* Do the first partial byte */
			
			if (sleft >= dleft)
			{
				bits = *bptr >> skew;
			}	
			else /* ( sleft < dleft ) */
			{
				bits = *bptr++ << cskew;
				if (count > sleft)
					bits += *bptr >> skew;
			}
			bits ^= invert;
			write_byte_masked(optr, bits, mask);
			count -= dleft;
			params.x_pos += 8;
			optr = mk_fb_ptr(params.x_pos,params.y_pos);
			
			/* Do full bytes. */
			
			while ( count >= 8 )
			{
				bits = *bptr++ << cskew;
				bits += *bptr >> skew;
				bits ^= invert;
				write_byte(optr, bits);
				count -= 8;
				params.x_pos += 8;
				optr = mk_fb_ptr(params.x_pos,params.y_pos);
			}
			
			/* Do last byte */
			
			if (count > 0)
			{
				bits = *bptr++ << cskew;
 				if (count > skew)
					bits += *bptr >> skew;
				bits ^= invert;
				write_byte_masked(optr, bits, rmask);
			}
/*			dest += BPL;
			line += raster;
*/
			params.y_pos++;
			params.x_pos = x;
			params.src += raster;
		}
	}
	return 0;
}

/* Copy a color pixelmap.  This is just like a bitmap, */
int
herc_copy_color(gx_device *dev,
  const byte *base, int sourcex, int raster, gx_bitmap_id id,
  int x, int y, int w, int h)
{	return herc_copy_mono(dev, base, sourcex, raster, id,
		x, y, w, h,(gx_color_index)0, (gx_color_index)1);
}

#  define mk_fb_yptr(x, y)\
    (fb_ptr)((regen) + ((0x2000 * ((y) % 4) + (90 * ((y) >> 2))) + x))

/* Fill a rectangle. */
int
herc_fill_rectangle(gx_device *dev, int x, int y, int w, int h,
  gx_color_index color)
{	rop_params params;

	int x2, y2, xlen;
	byte led, red, d;
	byte far *ptr;
	int xloc;

	fit_fill(dev, x, y, w, h);

	params.dest = mk_fb_ptr(x, y);
	params.y_pos = y;
	params.x_pos = x;

	x2 = x + w - 1;
	y2 = y + h - 1;

	xlen = (x2 >> 3) - (x >> 3) - 1;
	led = 0xff >> (x & 7);
	red = 0xff << (7 - (x2 & 7));

	ptr =  mk_fb_ptr(x,y);

	if (color)
	{
		/* here to set pixels */
		
		if (xlen == -1)
		{
			/* special for rectangles that fit in a byte */
			
			d = led & red;
			for(; h >= 0; h--, ptr = mk_fb_ptr(x,params.y_pos))
			{
				*ptr |= d;
				params.y_pos++;
			}
			return 0;
		}
		
		/* normal fill */
		
		xloc = params.x_pos >> 3;
		for(; h >= 0; h--, ptr = mk_fb_ptr(x,params.y_pos))
		{	register int x_count = xlen;
			register byte far *p = ptr;
			*p |= led;
/*			 params.x_pos += 8; */
			xloc++;
			 p = mk_fb_yptr(xloc,params.y_pos);
			while ( x_count-- ) {
				 *p = 0xff;
/*				 params.x_pos += 8; */
				xloc++;
				 p = mk_fb_yptr(xloc,params.y_pos);
				}
			*p |= red;
/*			params.x_pos = x; */
			xloc = params.x_pos >> 3;
			params.y_pos++;
		}
	}

	/* here to clear pixels */

	led = ~led;
	red = ~red;

	if (xlen == -1)
	{
		/* special for rectangles that fit in a byte */
		
		d = led | red;
		for(; h >= 0; h--, ptr  = mk_fb_ptr(x,params.y_pos))
			{
			*ptr &= d;
			params.y_pos++;
			}
		return 0;
	}

	/* normal fill */
		
	xloc = x >> 3;
	for(; h >= 0; h--, ptr = mk_fb_ptr(x,params.y_pos))
	{	register int x_count = xlen;
		register byte far *p = ptr;
		*p &= led;
/*		 params.x_pos += 8; */
		xloc++;
		 p = mk_fb_yptr(xloc,params.y_pos);
		while ( x_count-- ) {
			 *p = 0x00;
/*			 params.x_pos += 8; */
			xloc++;
			 p = mk_fb_yptr(xloc,params.y_pos);
			}
		*p &= red;
/*		params.x_pos = x; */
		xloc = params.x_pos >> 3;
		params.y_pos++;
	}
	return 0;
}