#include "insignia.h"
#include "host_def.h"
/*
 * SoftPC Revision 3.0
 *
 * Title	: vga_video.c
 *
 * Description	: BIOS video internal routines.
 *
 * Author	: William Gulland
 *
 * Notes	: The following functions are defined in this module:
 *
 *
 *
 */

/*
 * 	static char SccsID[]="@(#)vga_video.c	1.37 06/26/95 Copyright Insignia Solutions Ltd.";
 */


#ifdef VGG

#ifdef SEGMENTATION
/*
 * The following #include specifies the code segment into which this
 * module will by placed by the MPW C compiler on the Mac II running
 * MultiFinder.
 */
#include "VIDEO_BIOS_VGA.seg"
#endif

/*
 *    O/S include files.
 */
#include <stdio.h>
#include TypesH
#include FCntlH

/*
 * SoftPC include files
 */
#include "xt.h"
#include CpuH
#include "error.h"
#include "config.h"
#include "bios.h"
#include "ios.h"
#include "gmi.h"
#include "sas.h"
#include "gvi.h"
#include "timer.h"
#include "gfx_upd.h"
#include "host.h"
#include "egacpu.h"
#include "egaports.h"
#include "egagraph.h"
#include "egaread.h"
#include "video.h"
#include "egavideo.h"
#include "equip.h"
#include "vga_dac.h"
#include "vgaports.h"
#include "debug.h"

#ifndef PROD
#include "trace.h"
#endif

#include "host_gfx.h"

/*
 * ============================================================================
 * Global data
 * ============================================================================
 */


/*
 * ============================================================================
 * Local static data and defines
 * ============================================================================
 */

#define	DISABLE_REFRESH		0x20
/* the bit in the vga seq clock register that disables screen refresh */

#define VGA_COLOUR 8	/* Display Code */
typedef struct _rgb
{
	byte red;
	byte green;
	byte blue;
} rgb_struct;

/* internal function declarations */

/* To convert to grey, set all components to 30% r, 59% g and 11% b. */
static void greyify(rgb)
rgb_struct *rgb;
{
	unsigned int grey;

	grey = (30*rgb->red+59*rgb->green+11*rgb->blue)/100;
	rgb->red = rgb->green = rgb->blue = grey;
}

static void set_dac(dac,rgb)
half_word dac;
rgb_struct *rgb;
{
	if(is_GREY())greyify(rgb);
	outb(VGA_DAC_WADDR,dac);
	outb(VGA_DAC_DATA,rgb->red);
	outb(VGA_DAC_DATA,rgb->green);
	outb(VGA_DAC_DATA,rgb->blue);
}

static void get_dac(dac,rgb)
half_word dac;
rgb_struct *rgb;
{
	outb(VGA_DAC_RADDR,dac);
	inb(VGA_DAC_DATA,&(rgb->red));
	inb(VGA_DAC_DATA,&(rgb->green));
	inb(VGA_DAC_DATA,&(rgb->blue));
}


/*
 * ============================================================================
 * External functions
 * ============================================================================
 */


void init_vga_dac(table)
int table;	/* Which table to use */
{
    int loop;
    byte *dac;
    rgb_struct rgb;

#ifdef	macintosh

	/* load the required DAC in */
	dac = host_load_vga_dac (table);

	/* check it worked */
	if (!dac)
		return;

#else	/* macintosh */

    switch (table)
    {
	case 0: 
    	  dac = vga_dac;
	  break;
	case 1: 
    	  dac = vga_low_dac;
	  break;
	case 2:
	  dac = vga_256_dac;
          break;
	default:
	  assert1(FALSE,"Bad VGA DAC table %d",table);
    }

#endif	/* macintosh */

    for(loop = 0; loop < 0x100; loop++) 
	{
		rgb.red = *dac; rgb.green = dac[1]; rgb.blue = dac[2];
		set_dac(loop,&rgb);
		dac+=3;
    }

#ifdef	macintosh

	/* and dump the DAC back into the heap */
	host_dump_vga_dac ();

#endif	/* macintosh */
}

/***** Routines to handle VGA 256 colour modes, called from video.c **********/
GLOBAL VOID vga_graphics_write_char 
	IFN6( LONG, col, LONG, row, LONG, ch, IU8, colour, LONG, page, LONG, nchs)
{
	register sys_addr char_addr;
	register long screen_offset;
	register int i,j,k,char_height,len;
	register int scan_length = 8*sas_w_at_no_check(VID_COLS);
	register byte mask, val, bank;
	
	UNUSED(page);

	char_height = sas_hw_at_no_check(ega_char_height);
	char_addr = follow_ptr(EGA_FONT_INT*4)+char_height*ch;

/* VGA 256 colour mode has only one page, so ignore 'page' */

	/*
	 * Set read/write banks to zero to optimise the update_alg call
	 */

	set_banking( 0, 0 );

	screen_offset = row*scan_length*char_height+8*col;
	len = ( nchs << 3 ) - 1;

	for(i=0;i<char_height;i++)
	{
		(*update_alg.mark_fill)( screen_offset, screen_offset + len );

		val = sas_hw_at_no_check(char_addr);
		char_addr++;

		for(j=0;j<nchs;j++)
		{
			mask = 0x80;

			for(k=0;k<8;k++)
			{
				if( val & mask )
					*(IU8 *)(getVideowplane() + screen_offset) = colour;
				else
					*(IU8 *)(getVideowplane() + screen_offset) = 0;

				screen_offset++;
				mask = mask >> 1;
			}
		}

		screen_offset += scan_length - ( nchs << 3 );
	}

	/*
	 * Set read/write banks to last value in case someone relies on this side-effect
	 */

	bank = ( screen_offset - ( scan_length - ( nchs << 3 ))) >> 16;
	set_banking( bank, bank ); 
}

GLOBAL VOID vga_write_dot 
	IFN4(LONG, colour, LONG, page, LONG, pixcol, LONG, row)
{
#ifdef REAL_VGA
	register sys_addr screen_offset;

	screen_offset = video_pc_low_regen+8*row*sas_w_at_no_check(VID_COLS)+pixcol;
	sas_store(screen_offset, colour); /* WOW - that's easy!! */
#else
	long screen_offset;
	UTINY bank;
	
	UNUSED(page);

	screen_offset = (8*row*sas_w_at_no_check(VID_COLS)+pixcol);

	bank = screen_offset >> 16;
	set_banking( bank, bank ); 

	EGA_plane0123[screen_offset] = colour;
	(*update_alg.mark_byte)(screen_offset);
#endif	/* REAL_VGA */
}

GLOBAL VOID vga_sensible_graph_scroll_up 
	IFN6( LONG, row, LONG, col, LONG, rowsdiff, LONG, colsdiff, LONG, lines, LONG, attr)
{
	register int col_incr = 8*sas_w_at_no_check(VID_COLS);
	register int i;
	register long source,dest;
	register byte char_height;
	boolean screen_updated;

	col *= 8; colsdiff *= 8; /* 8 bytes per character */
	char_height = sas_hw_at_no_check(ega_char_height);
	rowsdiff *= char_height;
	lines *= char_height;
#ifdef REAL_VGA
	/* Not done for back M */
	dest = video_pc_low_regen+sas_loadw(VID_ADDR)+
		row*col_incr*char_height+col;
	source = dest+lines*col_incr;
	for(i=0;i<rowsdiff-lines;i++)
	{
		memcpy_16(dest,source,colsdiff);
		source += col_incr;
		dest += col_incr;
	}
	while(lines--)
	{
		memset_16(dest,attr,colsdiff);
		dest += col_incr;
	}
#else
	dest = sas_w_at_no_check(VID_ADDR)+ row*col_incr*char_height+col;
	source = dest+lines*col_incr;
	screen_updated = (col+colsdiff) <= col_incr;  /* Check for silly scroll */
	if(screen_updated)
		screen_updated = (*update_alg.scroll_up)(dest,colsdiff,rowsdiff,attr,lines,0);
	for(i=0;i<rowsdiff-lines;i++)
	{
		memcpy(&EGA_plane0123[dest],&EGA_plane0123[source],colsdiff);
		if(!screen_updated)
			(*update_alg.mark_string)(dest,dest+colsdiff-1);
		source += col_incr;
		dest += col_incr;
	}
	while(lines--)
	{
		memset(&EGA_plane0123[dest],attr,colsdiff);
		if(!screen_updated)
			(*update_alg.mark_fill)(dest,dest+colsdiff-1);
		dest += col_incr;
	}
#endif	/* REAL_VGA */
}

GLOBAL VOID vga_sensible_graph_scroll_down 
	IFN6( LONG, row, LONG, col, LONG, rowsdiff, LONG, colsdiff, LONG, lines, LONG, attr)
{
	register int col_incr = 8*sas_w_at_no_check(VID_COLS);
	register int i;
	register long source,dest;
	register byte char_height;
	boolean screen_updated;

	col *= 8; colsdiff *= 8; /* 8 bytes per character */
	char_height = sas_hw_at_no_check(ega_char_height);
	rowsdiff *= char_height;
	lines *= char_height;
#ifdef REAL_VGA
	/* Not done for back M */
	dest = video_pc_low_regen+sas_loadw(VID_ADDR)+
		row*col_incr*char_height+col;
	dest += (rowsdiff-1)*col_incr;
	source = dest-lines*col_incr;
	for(i=0;i<rowsdiff-lines;i++)
	{
		memcpy_16(dest,source,colsdiff);
		source -= col_incr;
		dest -= col_incr;
	}
	while(lines--)
	{
		memset_16(dest,attr,colsdiff);
		dest -= col_incr;
	}
#else
	dest = sas_w_at_no_check(VID_ADDR)+ row*col_incr*char_height+col;
	screen_updated = (col+colsdiff) <= col_incr;  /* Check for silly scroll */
	if(screen_updated)
		screen_updated = (*update_alg.scroll_down)(dest,colsdiff,rowsdiff,attr,lines,0);
	dest += (rowsdiff-1)*col_incr;
	source = dest-lines*col_incr;
	for(i=0;i<rowsdiff-lines;i++)
	{
		memcpy(&EGA_planes[dest],&EGA_planes[source],colsdiff);
		if(!screen_updated)
			(*update_alg.mark_string)(dest,dest+colsdiff-1);
		source -= col_incr;
		dest -= col_incr;
	}
	while(lines--)
	{
		memset(&EGA_planes[dest],attr,colsdiff);
		if(!screen_updated)
			(*update_alg.mark_fill)(dest,dest+colsdiff-1);
		dest -= col_incr;
	}
#endif	/* REAL_VGA */
}

GLOBAL VOID vga_read_attrib_char IFN3(LONG, col, LONG, row, LONG, page)
{
	byte the_char[256];
	register host_addr screen;
	register int i,k;
	register int scan_length = 8*sas_w_at_no_check(VID_COLS);
    register byte mask;
	byte char_height = sas_hw_at_no_check(ega_char_height);
	
	UNUSED(page);
	
/*printf("vga_read_attrib_char(%d,%d,%d)\n",
	col,row,page);*/
/* VGA 256 colour mode has only one page, so ignore 'page' */
#ifdef REAL_VGA
	screen = video_pc_low_regen+row*scan_length*char_height+8*col;
#else
	screen = &EGA_plane0123[row*scan_length*char_height+8*col];
#endif  /* REAL_VGA */
	for(i=0;i<char_height;i++)
	{
		mask = 0x80;
		the_char[i]=0;
		for(k=0;k<8;k++)
		{
			if(*screen++)
				the_char[i] |= mask;
			mask = mask >> 1;
		}
		screen += scan_length - 8;
	}
	search_font((char *)the_char,(int)char_height);
}

GLOBAL VOID vga_read_dot IFN3(LONG, page, LONG, pixcol, LONG, row)
{
	register host_addr screen;
	
	UNUSED(page);
	
/*printf("vga_read_dot(%d,%d,%d)\n",page,col,row);*/
#ifdef REAL_VGA
	screen = video_pc_low_regen+8*row*sas_w_at_no_check(VID_COLS)+pixcol;
#else
	screen = &EGA_plane0123[8*row*sas_w_at_no_check(VID_COLS)+pixcol];
#endif  /* REAL_VGA */
	setAL(*screen) ; /* WOW - that's easy!! */
}

/****** Routines to handle BIOS functions new to VGA *******/
void vga_set_palette()
{
	/*
	 * Called via INT 10 AH=10, AL='not understood by ega_set_palette()'
	 * Sets/reads VGA DACs.
	 */
	int i,dac;
	byte temp; /* For inb()s. */
	byte mode_reg;
	rgb_struct rgb_dac;
	sys_addr ptr;
	switch(getAL())
	{
		case 7:		/* Read attribute register */
			outb(EGA_AC_INDEX_DATA,getBL()); /* set index */
			inb(EGA_AC_SECRET,&temp);
			setBH(temp);
			inb(EGA_IPSTAT1_REG,&temp);
			outb(EGA_AC_INDEX_DATA, EGA_PALETTE_ENABLE);
			break;
		case 8:		/* Read overscan register */
			outb(EGA_AC_INDEX_DATA,17); /* overscan index */
			inb(EGA_AC_SECRET,&temp);
			setBH(temp);
			inb(EGA_IPSTAT1_REG,&temp);
			outb(EGA_AC_INDEX_DATA, EGA_PALETTE_ENABLE);
			break;
		case 9:		/* Read all palette regs. + overscan */
			ptr = effective_addr(getES(),getDX());
			for(i=0;i<16;i++)
			{
				outb(EGA_AC_INDEX_DATA,i); /* set index */
				inb(EGA_AC_SECRET,&temp);
				sas_store(ptr, temp);
				inb(EGA_IPSTAT1_REG,&temp);
				ptr++;
			}
			outb(EGA_AC_INDEX_DATA,17); /* overscan index */
			inb(EGA_AC_SECRET,&temp);
			sas_store(ptr, temp);
			inb(EGA_IPSTAT1_REG,&temp);
			outb(EGA_AC_INDEX_DATA, EGA_PALETTE_ENABLE);
			break;
		case 0x10:	/* Set one DAC */
			rgb_dac.red = getDH();
			rgb_dac.green = getCH();
			rgb_dac.blue = getCL();
			set_dac(getBX(),&rgb_dac);
			break;
		case 0x12:	/* Set block of DACs */
			ptr = effective_addr(getES(),getDX());
			dac = getBX();
			for(i=0;i<getCX();i++)
			{
			   rgb_dac.red = sas_hw_at_no_check(ptr);
			   rgb_dac.green = sas_hw_at_no_check(ptr+1);
			   rgb_dac.blue = sas_hw_at_no_check(ptr+2);
			   set_dac(dac,&rgb_dac);
			   dac++;ptr += 3;
			}
			break;
		case 0x13:	/* Set paging mode
				 * see Prog Guide to Video Systems, pp60-63]
				 * and IBM ROM BIOS pp26-27.
				 */
			outb(EGA_AC_INDEX_DATA,16); /* mode control index */
			inb(EGA_AC_SECRET,&mode_reg);  /* Old value */
			if(getBL()==0)
			{  /* Select paging mode */
			   outb(EGA_AC_INDEX_DATA,
				(mode_reg & 0x7f) | (getBH()<<7));
			}
			else /* Select a palette page */
			{
			   inb(EGA_IPSTAT1_REG,&temp);
			   outb(EGA_AC_INDEX_DATA,20); /* pixel padding index */
			   if(mode_reg & 0x80)
		   	    /* 16 entry palettes 
		   	     *  bits 0-3of the pad register relevant */
			     outb(EGA_AC_INDEX_DATA,getBH());
			   else
			    /* 64 entry palette - only bits 2-3 relevent */
			     outb(EGA_AC_INDEX_DATA,getBH()<<2);
			}
			inb(EGA_IPSTAT1_REG,&temp);
			outb(EGA_AC_INDEX_DATA, EGA_PALETTE_ENABLE);
			break;

		case 0x15:	/* Get value of one DAC */
			get_dac(getBX(),&rgb_dac);
			setDH(rgb_dac.red);
			setCH(rgb_dac.green);
			setCL(rgb_dac.blue);
			break;
		case 0x17:
			ptr = effective_addr(getES(),getDX());
			dac = getBX();
			for(i=0;i<getCX();i++)
			{
			   get_dac(dac,&rgb_dac);
			   sas_store(ptr, rgb_dac.red);
			   sas_store(ptr+1, rgb_dac.green);
			   sas_store(ptr+2, rgb_dac.blue);
			   dac++;
			   ptr += 3;
			}
			break;
		case 0x18:
			/* Set the VGA DAC mask. */
			outb(VGA_DAC_MASK,getBL());
			break;
		case 0x19:
			/* Get the VGA DAC mask. */
			inb(VGA_DAC_MASK,&temp);
			setBL(temp);
			break;
		case 0x1a:
			/* Return current mode control & pixel padding */
			outb(EGA_AC_INDEX_DATA,16); /* mode control index */
			inb(EGA_AC_SECRET,&mode_reg);
			if(mode_reg & 0x80)
				setBL(1);
			else
				setBL(0);
			inb(EGA_IPSTAT1_REG,&temp);
			outb(EGA_AC_INDEX_DATA,20); /* pixel padding index */
			inb(EGA_AC_SECRET,&temp);
			setBH(temp);
			inb(EGA_IPSTAT1_REG,&temp);
			outb(EGA_AC_INDEX_DATA, EGA_PALETTE_ENABLE);
			break;
		case 0x1b:	/* Convert set of DACs to grey scale. */
			dac = getBX();
			for(i=0;i<getCX();i++)
			{
				get_dac(dac,&rgb_dac);
				greyify(&rgb_dac);
				set_dac(dac,&rgb_dac);
				dac++;
			}
			break;
		default:
			assert1(FALSE,"Bad set palette submode %#x",getAL());
			break;
	}
}

/* 
 * Various miscellaneous flags can be set using
 * INT 10, AH 12, AL flag.
 * Called from ega_alt_sel().
 */
void vga_func_12()
{
	half_word	seq_clock;

	switch(getBL())
	{
		case 0x30:	/* Set number of scan lines */
			if(getAL() == 0)
				set_VGA_lines(S200);
			else if(getAL() == 1)
				set_VGA_lines(S350);
			else
				set_VGA_lines(S400);
			setAL(0x12);	/* We did it */
			break;
		case 0x33:	/* Enable/Disable Grey-Scale Summing */
			if(getAL())
				set_GREY(0);
			else
				set_GREY(GREY_SCALE);
			setAL(0x12);	/* We did it */
			break;
		case 0x34:	/* Enable/disable Cursor Emulation */
			set_EGA_cursor_no_emulate(getAL() & 1);	
			setAL(0x12);	/* We did it */
			break;

		case 0x36:	/* Enable/Disable Screen Refresh */
			if (getAL() == 0)
			{
				outb(EGA_SEQ_INDEX, 1);
				inb(EGA_SEQ_DATA, &seq_clock);
				outb(EGA_SEQ_DATA, seq_clock & ~DISABLE_REFRESH);
			}
			else
			{
				outb(EGA_SEQ_INDEX, 1);
				inb(EGA_SEQ_DATA, &seq_clock);
				outb(EGA_SEQ_DATA, seq_clock | DISABLE_REFRESH);
			}
			setAL(0x12);
			break;
		case 0x31:	/* Enable/Disable Default Palette Loading */
		case 0x32:	/* Enable/Disable Video */
		case 0x35:	/* Switch active display */
			/* do not set code that means it worked */
		default:
			setAL(0);	/* Function not supported */
			break;
	}
}
void vga_disp_comb()
{
	/* check that we really are a VGA */
	if (video_adapter != VGA)
	{
		/* we are not -so this function is not implemented */
		not_imp();
		return;
	}

	/*
	 * On a PS/2, AL=1 is (I believe) used to switch active displays. 
	 * We ignore this.
	 * AL=0 returns the current display, which we can cope with.
	 */
	if(getAL() == 0)
	{
		setBH(0);	   /* Only one display, so no inactive one! */
		setBL(VGA_COLOUR); /* VGA with colour monitor. (7 for mono) */
	}
	setAX(0x1A); /* Tell him we coped. */
}

void vga_disp_func()
{
	/* 
	 * This function returns masses of info. about the current 
	 * display and screen mode.
	 * One of the things returned is a pointer to the display info.
	 * This is stored in the VGA ROM, so all we need to do is set 
	 * the pointer up.
	 *
	 */
	sys_addr buf = effective_addr(getES(),getDI());
	byte temp,mode_reg, video_mode;

#if defined(NTVDM) && defined(X86GFX)
	IMPORT word vga1b_seg, vga1b_off;
#endif	/* NTVDM & X86GFX */

	/* check that we really are a VGA */
#ifndef HERC 
	if (video_adapter != VGA)
#else
	if ( (video_adapter != VGA) && (video_adapter != HERCULES))
#endif	/* HERC */
	{
		/* we are not -so this function is not implemented */
		not_imp();
		return;
	}

#ifdef HERC 
     if( video_adapter == VGA)
     {
#endif	/* HERC */
	video_mode = sas_hw_at_no_check(vd_video_mode);
#ifdef V7VGA
	if ((video_mode == 1) && extensions_controller.foreground_latch_1)
		video_mode = extensions_controller.foreground_latch_1;
	else if (video_mode > 0x13)
		video_mode += 0x4c;
#endif /* V7VGA */

/*
 * Store VGA capability table pointer. Usually lives in Insignia ROM, on NT
 * x86 it has to live in ntio.sys.
 */
#if defined(NTVDM) && defined(X86GFX)
	sas_storew(buf, vga1b_off);
	sas_storew(buf+2, vga1b_seg);
#else
	sas_storew(buf,INT10_1B_DATA);
	sas_storew(buf+2,EGA_SEG);
#endif	/* NTVDM & X86GFX */

	sas_store(buf+0x4, video_mode);	/* Current video mode */
	sas_storew(buf+5,sas_w_at_no_check(VID_COLS)); /* Cols on screen */
	sas_storew(buf+7,sas_w_at_no_check(VID_LEN));  /* Size of screen */
	sas_storew(buf+9,sas_w_at_no_check(VID_ADDR)); /* Address of screen */
	sas_move_bytes_forward(VID_CURPOS,buf+0xB,16);	    /* Cursor positions */
	sas_storew(buf+0x1b,sas_w_at_no_check(VID_CURMOD)); /* Cursor type */
	sas_store(buf+0x1D, sas_hw_at_no_check(vd_current_page));
	sas_storew(buf+0x1E,sas_w_at_no_check(VID_INDEX));
	sas_store(buf+0x20, sas_hw_at_no_check(vd_crt_mode));
	sas_store(buf+0x21, sas_hw_at_no_check(vd_crt_palette));
	sas_store(buf+0x22, sas_hw_at_no_check(vd_rows_on_screen)+1);
	sas_storew(buf+0x23,sas_w_at_no_check(ega_char_height));
	sas_store(buf+0x25, VGA_COLOUR);	/* Active display */
	sas_store(buf+0x26, 0);		/* Inactive display (none) */
#ifdef V7VGA
	if (video_mode >= 0x60)
	{
		sas_storew(buf+0x27,vd_ext_graph_table[video_mode-0x60].ncols);
		sas_store(buf+0x29, vd_ext_graph_table[video_mode-0x60].npages);
	}
	else if (video_mode >= 0x40)
	{
		sas_storew(buf+0x27,vd_ext_text_table[video_mode-0x40].ncols);
		sas_store(buf+0x29, vd_ext_text_table[video_mode-0x40].npages);
	}
	else 
	{
		sas_storew(buf+0x27,vd_mode_table[video_mode].ncols);
		sas_store(buf+0x29, vd_mode_table[video_mode].npages);
	}
#else
	sas_storew(buf+0x27,vd_mode_table[video_mode].ncols);
	sas_store(buf+0x29, vd_mode_table[video_mode].npages);
#endif /* V7VGA */
	sas_store(buf+0x2A, get_scanlines());

	outb(EGA_SEQ_INDEX,3);
	inb(EGA_SEQ_DATA,&temp);	/* Character Font select reg. */
	sas_store(buf+0x2B, (temp & 3)|((temp & 0x10)>>2));
			 /* extract bits 410 - font B */
	sas_store(buf+0x2C, ((temp & 0xC)>>2)|((temp & 0x20)>>3));
			/* extract bits 532 - font A */

	temp = 1;			/* All modes on all displays active */
	if(is_GREY())temp |= 2;
	if(is_MONO())temp |= 4;
	if(is_PAL_load_off())temp |=8;
	if(get_EGA_cursor_no_emulate())temp |= 0x10;
	inb(EGA_IPSTAT1_REG,&mode_reg); /* Clear Attribute flip-flop */
	outb(EGA_AC_INDEX_DATA,16); /* mode control index */
	inb(EGA_AC_SECRET,&mode_reg);
	if(mode_reg & 8)temp |= 0x20;
	inb(EGA_IPSTAT1_REG,&mode_reg);	/* Clear Attribute flip-flop */
	outb(EGA_AC_INDEX_DATA, EGA_PALETTE_ENABLE);
	sas_store(buf+0x2D, temp);
	sas_store(buf+0x31, 3);		/* 256KB video memory */
	setAX(0x1B); /* We did it! */
#ifdef HERC 
       } /* if VGA */
    if( video_adapter == HERCULES)
     {
	video_mode = sas_hw_at(vd_video_mode);
	sas_storew(buf,INT10_1B_DATA);
	sas_storew(buf+2,EGA_SEG);
	sas_store(buf+0x4, video_mode);				/* Current video mode */
	sas_storew(buf+5,sas_w_at(VID_COLS)); 			/* Cols on screen */
	sas_storew(buf+7,sas_w_at(VID_LEN));  			/* Size of screen */
	sas_storew(buf+9,sas_w_at(VID_ADDR)); 			/* Address of screen */
	sas_move_bytes_forward(VID_CURPOS,buf+0xB,16);	    	/* Cursor positions */
	sas_store(buf+0x1b, HERC_CURS_START+HERC_CURS_HEIGHT);  /* Cursor end line */
	sas_store(buf+0x1c, HERC_CURS_START);		   	/* Cursor start line */
	sas_store(buf+0x1D, sas_hw_at(vd_current_page));	
	sas_storew(buf+0x1E,sas_w_at(VID_INDEX));
	sas_store(buf+0x20, sas_hw_at(vd_crt_mode));
	sas_store(buf+0x21, sas_hw_at(vd_crt_palette));
	sas_store(buf+0x22, sas_hw_at(vd_rows_on_screen)+1);
	sas_storew(buf+0x23, 14);				/* char height is 14 */
	sas_store(buf+0x25,0x01 );	/* 01=MDA with monochrome display as Active display */
	sas_store(buf+0x26, 0);		/* Inactive display (none) */

	vd_mode_table[video_mode].ncols= 2;			/* Black & White 2 colors */
	sas_storew(buf+0x27,vd_mode_table[video_mode].ncols);
	vd_mode_table[video_mode].npages= 2;			/* support 2 pages  */
	sas_store(buf+0x29, vd_mode_table[video_mode].npages);

	sas_store(buf+0x2A, get_scanlines());

	sas_store(buf+0x2B,0x00);	/* Primary Font select always 0 */
	sas_store(buf+0x2C,0x00);	/* Secondary Font select always 0 */


	sas_store(buf+0x2D, 0x30);	/* MDA with Monochrome Display */
	sas_store(buf+0x31, 0);		/* 64KB video memory */
	setAX(0x1B); /* We did it! */
       } /* if HERCULES */
#endif	/* HERC */
}

void vga_int_1C()
{
sys_addr buff = effective_addr(getES(),getBX());
int i;
word states;
half_word temp;
rgb_struct rgb_dac;
static word buff_sizes[] = { 0,2,2,3,0x0d,0x0e,0x0e,0x0f };
static byte const1[] = { 2,0x18,6,0x20 };
static byte const2[] = { 0xd4,3,0x20,7,0,0 };
static byte const3[] = { 0x20 };
static byte const4[] = { 0x68,0x15,0x20,0x0a,0x85,0,0,0xc0,0,0x0c,0,0xc0,0,8,0,0xc0 };
static byte const5[] = { 1,0,0xff };

	/* check that we really are a VGA */
	if (video_adapter != VGA)
	{
		/* we are not -so this function is not implemented */
		not_imp();
		return;
	}
	states = getCX() & 7;
	switch (getAL())
	{
	case 00:  /* buffer sizes into bx */
		setBX(buff_sizes[states]);
		setAL(0x1c);
		break;

	case 01:  /* Save video states to es:bx */
		if( states&1 )  /* Video hardware state */
			sas_storew(buff, 0x0064); /* ID words. DODGY! */
		if( states&2 )  /* Video BIOS state */
			sas_storew(buff+2, 0x0064);
		if( states&4 )  /* Video DAC state */
			sas_storew(buff+4, 0x0064);
		buff += 0x20;

		if( states&1 )  /* Video hardware state */
		{
			for(i=0;i<sizeof(const1);i++)
				sas_store(buff++, const1[i]);
			for(i=0;i<5;i++)
			{
				outb(EGA_SEQ_INDEX,i);
				inb(EGA_SEQ_DATA,&temp);
				sas_store(buff++, temp);
			}
			inb(VGA_MISC_READ_REG,&temp);
			sas_store(buff++, temp);
			for(i=0;i<0x19;i++)
			{
				outb(EGA_CRTC_INDEX,i);
				inb(EGA_CRTC_DATA,&temp);
				sas_store(buff++, temp);
			}
			for(i=0;i<20;i++)
			{
				inb(EGA_IPSTAT1_REG,&temp); /*clear attribute flipflop*/
				outb(EGA_AC_INDEX_DATA,i);
				inb(EGA_AC_SECRET,&temp);
				sas_store(buff++, temp);
			}
			/* now ensure video reenabled. First ensure
			 * AC reg is in 'index' state by reading Status reg 1
			 */
			inb(EGA_IPSTAT1_REG,&temp);
			outb(EGA_AC_INDEX_DATA, EGA_PALETTE_ENABLE);
			for(i=0;i<9;i++)
			{
				outb(EGA_GC_INDEX,i);
				inb(EGA_GC_DATA,&temp);
				sas_store(buff++, temp);
			}
			for(i=0;i<sizeof(const2);i++)
				sas_store(buff++, const2[i]);
		}
		if( states&2 )  /* Video BIOS state  */
		{
			for(i=0;i<sizeof(const3);i++)
				sas_store(buff++, const3[i]);
			sas_store(buff++, sas_hw_at_no_check(vd_video_mode));
			sas_storew(buff,sas_w_at_no_check(VID_COLS));
			buff += 2;
			sas_storew(buff,sas_w_at_no_check(VID_LEN));
			buff += 2;
			sas_storew(buff,sas_w_at_no_check(VID_ADDR));
			buff += 2;
			sas_move_bytes_forward(VID_CURPOS, buff, 16);
			buff += 16;
			outb(EGA_CRTC_INDEX,R11_CURS_END);
			inb(EGA_CRTC_DATA,&temp);
			sas_store(buff++, temp & 0x1F);
			outb(EGA_CRTC_INDEX,R10_CURS_START);
			inb(EGA_CRTC_DATA,&temp);
			sas_store(buff++, temp & 0x1F);
			sas_store(buff++, sas_hw_at_no_check(vd_current_page));
			sas_storew(buff,sas_w_at_no_check(VID_INDEX));
			buff += 2;
			sas_store(buff++, sas_hw_at_no_check(vd_crt_mode));
			sas_store(buff++, sas_hw_at_no_check(vd_crt_palette));
			sas_store(buff++, sas_hw_at_no_check(vd_rows_on_screen));
			sas_storew(buff, sas_w_at_no_check(ega_char_height));
			buff += 2;
			sas_store(buff++, sas_hw_at_no_check(ega_info));
			sas_store(buff++, sas_hw_at_no_check(ega_info3));
			sas_store(buff++, sas_hw_at_no_check(VGA_FLAGS));
			sas_store(buff++, sas_hw_at_no_check(0x48a)); /* DCC */
			sas_move_bytes_forward(EGA_SAVEPTR, buff, 4);
			buff += 4;

			for(i=0;i<sizeof(const4);i++)
				sas_store(buff++, const4[i]);
		}
		if( states&4 )  /* VGA DAC values  */
		{
			for(i=0;i<sizeof(const5);i++)
				sas_store(buff++, const5[i]);
			for(i=0;i<256;i++)
			{
				get_dac(i, &rgb_dac);
				sas_store(buff++, rgb_dac.red);
				sas_store(buff++, rgb_dac.green);
				sas_store(buff++, rgb_dac.blue);
			}
		}
		break;

	case 02:  /* Restore video states from es:bx */
		buff += 0x20;
		if( states&1 )  /* Video hardware state */
		{
			buff += sizeof(const1);
			for(i=0;i<5;i++)
			{
				outb(EGA_SEQ_INDEX,i);
				outb(EGA_SEQ_DATA,sas_hw_at_no_check(buff++));
			}
			outb(VGA_MISC_READ_REG,sas_hw_at_no_check(buff++));
			for(i=0;i<0x19;i++)
			{
				outb(EGA_CRTC_INDEX,i);
				outb(EGA_CRTC_DATA,sas_hw_at_no_check(buff++));
			}
			inb(EGA_IPSTAT1_REG,&temp); /* clear attribute flip flop */
			for(i=0;i<20;i++)
			{
				outb(EGA_AC_INDEX_DATA,i);
				outb(EGA_AC_INDEX_DATA,sas_hw_at_no_check(buff++));
			}
			outb(EGA_AC_INDEX_DATA, EGA_PALETTE_ENABLE);
			for(i=0;i<9;i++)
			{
				outb(EGA_GC_INDEX,i);
				outb(EGA_GC_DATA,sas_hw_at_no_check(buff++));
			}
			buff += sizeof(const2);
		}
		if( states&2 )  /* Video BIOS state  */
		{
			buff += sizeof(const3);
			sas_store_no_check(vd_video_mode, sas_hw_at_no_check(buff++));
			sas_storew_no_check(VID_COLS,sas_w_at_no_check(buff));
			buff += 2;
			sas_storew_no_check(VID_LEN,sas_w_at_no_check(buff));
			buff += 2;
			sas_storew_no_check(VID_ADDR,sas_w_at_no_check(buff));
			buff += 2;
			sas_move_bytes_forward(buff, VID_CURPOS, 16);
			buff += 16;
			outb(EGA_CRTC_INDEX,R11_CURS_END);
			temp = sas_hw_at_no_check(buff++) & 0x1F;
			outb(EGA_CRTC_DATA,temp);
			outb(EGA_CRTC_INDEX,R10_CURS_START);
			temp = sas_hw_at_no_check(buff++) & 0x1F;
			outb(EGA_CRTC_DATA,temp);
			sas_store_no_check(vd_current_page, sas_hw_at_no_check(buff++));
			sas_storew_no_check(VID_INDEX,sas_w_at_no_check(buff));
			buff += 2;
			sas_store_no_check(vd_crt_mode, sas_hw_at_no_check(buff++));
			sas_store_no_check(vd_crt_palette, sas_hw_at_no_check(buff++));
			sas_store_no_check(vd_rows_on_screen, sas_hw_at_no_check(buff++));
			sas_storew_no_check(ega_char_height, sas_w_at_no_check(buff));
			buff += 2;
			sas_store_no_check(ega_info, sas_hw_at_no_check(buff++));
			sas_store_no_check(ega_info3, sas_hw_at_no_check(buff++));
			sas_store_no_check(VGA_FLAGS, sas_hw_at_no_check(buff++));
			sas_store_no_check(0x48a, sas_hw_at_no_check(buff++)); /* DCC */
			sas_move_bytes_forward(buff, EGA_SAVEPTR, 4);
			buff += 4;
			buff += sizeof(const4);
		}
		if( states&4 )  /* VGA DAC values  */
		{
			buff += sizeof(const5);
			for(i=0;i<256;i++)
			{
				rgb_dac.red = sas_hw_at_no_check(buff++);
				rgb_dac.green = sas_hw_at_no_check(buff++);
				rgb_dac.blue = sas_hw_at_no_check(buff++);
				set_dac(i,&rgb_dac); 
			}
		}
		break;

	default:
		not_imp();
		break;
	}
}

#endif  /* VGG */