/***************************************************************************

  Monochrome Display Adapter (MDA) section

***************************************************************************/

#include "vidhrdw/generic.h"
#include "includes/crtc6845.h"

#include "vidhrdw/pc_mda.h"
#include "vidhrdw/pc_cga.h" //for the cga palette hack
#include "mscommon.h"

#define VERBOSE_MDA 0		/* MDA (Monochrome Display Adapter) */

#if VERBOSE_MDA
#define MDA_LOG(N,M,A) \
	if(VERBOSE_MDA>=N){ if( M )logerror("%11.6f: %-24s",timer_get_time(),(char*)M ); logerror A; }
#else
#define MDA_LOG(n,m,a)
#endif

unsigned char mda_palette[4][3] = {
	{ 0x00,0x00,0x00 },
	{ 0x00,0x55,0x00 }, 
	{ 0x00,0xaa,0x00 }, 
	{ 0x00,0xff,0x00 }
};

gfx_layout pc_mda_charlayout =
{
	9,32,					/* 9 x 32 characters (9 x 15 is the default, but..) */
	256,					/* 256 characters */
	1,                      /* 1 bits per pixel */
	{ 0 },                  /* no bitplanes; 1 bit per pixel */
	/* x offsets */
	{ 0,1,2,3,4,5,6,7,7 },	/* pixel 7 repeated only for char code 176 to 223 */
	/* y offsets */
	{ 0*8, 1*8, 2*8, 3*8, 4*8, 5*8, 6*8, 7*8,
	  16384+0*8, 16384+1*8, 16384+2*8, 16384+3*8,
	  16384+4*8, 16384+5*8, 16384+6*8, 16384+7*8,
	  0*8, 1*8, 2*8, 3*8, 4*8, 5*8, 6*8, 7*8,
	  16384+0*8, 16384+1*8, 16384+2*8, 16384+3*8,
	  16384+4*8, 16384+5*8, 16384+6*8, 16384+7*8 },
	8*8 					/* every char takes 8 bytes (upper half) */
};

gfx_decode pc_mda_gfxdecodeinfo[] =
{
	{ 1, 0x0000, &pc_mda_charlayout,		0, 256 },
    { -1 } /* end of array */
};

/* to be done:
   only 2 digital color lines to mda/hercules monitor
   (maximal 4 colors) 
   PC200 uses different attributes from IBM.
*/
unsigned short mda_colortable[] =
{
	0, 0, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 0, 0,10, 0,10, 0,10, 0,10, 0,10, 0,10, 0,10,
	0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0,10, 0,10, 0,10, 0,10, 0,10, 0,10, 0,10, 0,10,
	0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0,10, 0,10, 0,10, 0,10, 0,10, 0,10, 0,10, 0,10,
	0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0,10, 0,10, 0,10, 0,10, 0,10, 0,10, 0,10, 0,10,
	0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0,10, 0,10, 0,10, 0,10, 0,10, 0,10, 0,10, 0,10,
	0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0,10, 0,10, 0,10, 0,10, 0,10, 0,10, 0,10, 0,10,
	0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0,10, 0,10, 0,10, 0,10, 0,10, 0,10, 0,10, 0,10,
	2, 0, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 2, 0, 0,10, 0,10, 0,10, 0,10, 0,10, 0,10, 0,10,
/* nb: This---------------------------------------------^ should refer to a "dim" colour which
 * we don't do yet */

/* flashing is done by dirtying the videoram buffer positions with attr bit #7 set 
 * These attributes are used for the flashing characters when they're visible. */
	0, 0, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 0, 0,10, 0,10, 0,10, 0,10, 0,10, 0,10, 0,10,
	0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0,10, 0,10, 0,10, 0,10, 0,10, 0,10, 0,10, 0,10,
	0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0,10, 0,10, 0,10, 0,10, 0,10, 0,10, 0,10, 0,10,
	0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0,10, 0,10, 0,10, 0,10, 0,10, 0,10, 0,10, 0,10,
	0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0,10, 0,10, 0,10, 0,10, 0,10, 0,10, 0,10, 0,10,
	0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0,10, 0,10, 0,10, 0,10, 0,10, 0,10, 0,10, 0,10,
	0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0,10, 0,10, 0,10, 0,10, 0,10, 0,10, 0,10, 0,10,
	2, 0, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 2, 0, 0,10, 0,10, 0,10, 0,10, 0,10, 0,10, 0,10,

/* the two colors for HGC graphics */
	0, 10
};

/* Initialise the mda palette */
PALETTE_INIT( pc_mda )
{
	int i;
	for(i = 0; i < (sizeof(cga_palette) / 3); i++)
		palette_set_color(i, cga_palette[i][0], cga_palette[i][1], cga_palette[i][2]);
    memcpy(colortable, mda_colortable, sizeof(mda_colortable));
}

static struct
{
	UINT8 status;

	int pc_blink;
	int pc_framecnt;

	UINT8 mode_control, configuration_switch; //hercules

	gfx_element *gfx_char[4];
} mda;

/***************************************************************************

  Monochrome Display Adapter (MDA) section

***************************************************************************/

/***************************************************************************
  Mark all text positions with attribute bit 7 set dirty
 ***************************************************************************/
static void pc_mda_blink_textcolors(int on)
{
	int i, offs, size;

	if (mda.pc_blink == on) return;

    mda.pc_blink = on;
	offs = (crtc6845_get_start(crtc6845)*2)% videoram_size;
	size = crtc6845_get_char_lines(crtc6845)*crtc6845_get_char_columns(crtc6845);

	if (dirtybuffer)
	{
		for (i = 0; i < size; i++)
		{
			if (videoram[offs+1] & 0x80)
				dirtybuffer[offs+1] = 1;
			if ((offs += 2) == videoram_size)
				offs = 0;
		}
	}
}

extern void pc_mda_timer(void)
{
	if( ((++mda.pc_framecnt & 63) == 63) ) {
		pc_mda_blink_textcolors(mda.pc_framecnt&64);
	}
}

void pc_mda_cursor(struct crtc6845_cursor *cursor)
{
	if (dirtybuffer)
		dirtybuffer[cursor->pos*2]=1;
}

static struct crtc6845_config config= { 14318180 /*?*/, pc_mda_cursor };


/* This code seems to go through hoops to accomodate differing GfxElement
 * layouts.  What ugly crap */
static void pc_mda_init_video_internal(int gfx_char, int gfx_char_mask)
{
	int i, y;

	/* Support up to 4 fonts for PC200 */
	for (i = 0; i < 4; i++) 
	{
		mda.gfx_char[i] = Machine->gfx[gfx_char + (i & gfx_char_mask)];
	}

	/* remove pixel column 9 for character codes 0 - 191 and 224 - 255 */
	for (i = 0; i < 256; i++)
	{
		if (i < 191 || i > 223)
		{
			for (y = 0; y < Machine->gfx[gfx_char]->height; y++)
				Machine->gfx[gfx_char]->gfxdata[(i * Machine->gfx[gfx_char]->height + y) * Machine->gfx[gfx_char]->width + 8] = 0;
		}
	}
}

void pc_mda_init_video(void)
{
	pc_mda_init_video_internal(0, 0);
}

void pc_mda_europc_init(void)
{
	pc_mda_init_video_internal(4, 3);
}

VIDEO_START( pc_mda )
{
	pc_mda_init_video();
	return pc_video_start(&config, pc_mda_choosevideomode, videoram_size) ? INIT_PASS : INIT_FAIL;
}

/*
 *	rW	MDA mode control register (see #P138)
 */
static void hercules_mode_control_w(int data)
{
	MDA_LOG(1,"MDA_mode_control_w",(errorlog, "$%02x: colums %d, gfx %d, enable %d, blink %d\n",
		data, (data&1)?80:40, (data>>1)&1, (data>>3)&1, (data>>5)&1));
	mda.mode_control = data;
	schedule_full_refresh();
}

/*	R-	CRT status register (see #P139)
 *		(EGA/VGA) input status 1 register
 *		7	 HGC vertical sync in progress
 *		6-4  adapter 000  hercules
 *					 001  hercules+
 *					 101  hercules InColor
 *					 else unknown
 *		3	 pixel stream (0 black, 1 white)
 *		2-1  reserved
 *		0	 horizontal drive enable
 */
static int pc_mda_status_r(void)
{
    int data = (input_port_0_r(0) & 0x80) | 0x08 | mda.status;
	mda.status ^= 0x01;
	return data;
}

static void hercules_config_w(int data)
{
	MDA_LOG(1,"HGC_config_w",(errorlog, "$%02x\n", data));
    mda.configuration_switch = data;
	schedule_full_refresh();
}

/*************************************************************************
 *
 *		MDA
 *		monochrome display adapter
 *
 *************************************************************************/
WRITE8_HANDLER ( pc_MDA_w )
{
	switch( offset )
	{
		case 0: case 2: case 4: case 6:
			crtc6845_port_w(crtc6845, 0, data);
			break;
		case 1: case 3: case 5: case 7:
			crtc6845_port_w(crtc6845, 1, data);
			break;
		case 8:
			hercules_mode_control_w(data);
			break;
		case 15:
			hercules_config_w(data);
			break;
	}
}

 READ8_HANDLER ( pc_MDA_r )
{
	int data = 0xff;
	switch( offset )
	{
		case 0: case 2: case 4: case 6:
			data = crtc6845_port_r(crtc6845,0);
			break;
		case 1: case 3: case 5: case 7:
			data = crtc6845_port_r(crtc6845,1);
			break;
		case 10:
			data = pc_mda_status_r();
			break;
		/* 12, 13, 14  are the LPT1 ports */
    }
	return data;
}

/***************************************************************************
  Draw text mode with 80x25 characters (default) and intense background.
  The character cell size is 9x15. Column 9 is column 8 repeated for
  character codes 176 to 223.
***************************************************************************/
static void mda_text_inten(mame_bitmap *bitmap, struct crtc6845 *crtc)
{
	int sx, sy;
	int	offs = crtc6845_get_start(crtc)*2;
	int lines = crtc6845_get_char_lines(crtc);
	int height = crtc6845_get_char_height(crtc);
	int columns = crtc6845_get_char_columns(crtc);
	int char_width;
	rectangle r;
	struct crtc6845_cursor cursor;
	UINT8 attr;

	char_width = Machine->drv->screen_width / 80;

	crtc6845_time(crtc);
	crtc6845_get_cursor(crtc, &cursor);

	for (sy=0, r.min_y=0, r.max_y=height-1; sy<lines; sy++, r.min_y+=height,r.max_y+=height) {

		for (sx=0, r.min_x=0, r.max_x = char_width-1; sx<columns; 
			 sx++, offs=(offs+2)&0x3fff, r.min_x += char_width, r.max_x += char_width) {
			if (!dirtybuffer || dirtybuffer[offs] || dirtybuffer[offs+1]) {
				
				attr = videoram[offs+1];	
				drawgfx(bitmap, mda.gfx_char[CGA_FONT], videoram[offs], attr,
						0,0,r.min_x,r.min_y,&r,TRANSPARENCY_NONE,0);
				/* Underlining */ 
				if ((attr & 7) == 1) 
					plot_box(bitmap, r.min_x, r.min_y + 12, char_width, 
						1, Machine->pens[2 + (attr & 8)]);

				if (cursor.on&&(mda.pc_framecnt&32)&&(offs==cursor.pos*2)) {
					int k=height-cursor.top;
					rectangle rect2=r;
					rect2.min_y+=cursor.top; 
					if (cursor.bottom<height) k=cursor.bottom-cursor.top+1;

					if (k>0)
						plot_box(bitmap, r.min_x, 
								 r.min_y+cursor.top, 
								 char_width, k, Machine->pens[2/*?*/]);
				}

				if (dirtybuffer)
					dirtybuffer[offs] = dirtybuffer[offs+1] = 0;
			}
		}
	}
}


/***************************************************************************
  Draw text mode with 80x25 characters (default) and blinking characters.
  The character cell size is 9x15. Column 9 is column 8 repeated for
  character codes 176 to 223.
***************************************************************************/
static void mda_text_blink(mame_bitmap *bitmap, struct crtc6845 *crtc)
{
	int sx, sy;
	int	offs = crtc6845_get_start(crtc)*2;
	int lines = crtc6845_get_char_lines(crtc);
	int height = crtc6845_get_char_height(crtc);
	int columns = crtc6845_get_char_columns(crtc);
	rectangle r;
	struct crtc6845_cursor cursor;
	int char_width;

	char_width = Machine->drv->screen_width / 80;

	crtc6845_time(crtc);
	crtc6845_get_cursor(crtc, &cursor);

	for (sy=0, r.min_y=0, r.max_y=height-1; sy<lines; sy++, r.min_y+=height,r.max_y+=height) {

		for (sx=0, r.min_x=0, r.max_x = char_width-1; sx<columns; 
			 sx++, offs=(offs+2)&0x3fff, r.min_x += char_width, r.max_x += char_width) {

			if (!dirtybuffer || dirtybuffer[offs] || dirtybuffer[offs+1]) {
				
				int attr = videoram[offs+1];
				if (attr & 0x80)	/* blinking ? */
				{
					if (mda.pc_blink) attr = 0;
				}

				drawgfx(bitmap, mda.gfx_char[CGA_FONT], videoram[offs], attr,
						0,0,r.min_x,r.min_y,&r,TRANSPARENCY_NONE,0);
				/* Underlining */ 
				if ((attr & 7) == 1) 
					plot_box(bitmap, r.min_x, r.min_y + 12, char_width, 
						1, Machine->pens[2 + (attr & 8)]);

//				if ((cursor.on)&&(offs==cursor.pos*2)) {
				if (cursor.on&&(mda.pc_framecnt&32)&&(offs==cursor.pos*2)) {
					int k=height-cursor.top;
					rectangle rect2=r;
					rect2.min_y+=cursor.top; 
					if (cursor.bottom<height) k=cursor.bottom-cursor.top+1;

					if (k>0)
						plot_box(bitmap, r.min_x, 
								 r.min_y+cursor.top, 
								 char_width, k, Machine->pens[2/*?*/]);
				}

				if (dirtybuffer)
					dirtybuffer[offs] = dirtybuffer[offs+1] = 0;
			}
		}
	}
}

/***************************************************************************
  Draw graphics with 720x384 pixels (default); so called Hercules gfx.
  The memory layout is divided into 4 banks where of size 0x2000.
  Every bank holds data for every n'th scanline, 8 pixels per byte,
  bit 7 being the leftmost.
***************************************************************************/

static void hercules_gfx(mame_bitmap *bitmap, struct crtc6845 *crtc)
{
	const UINT8 *vram = videoram;
	static const UINT16 palette[2] = {0, 10};

	if (mda.mode_control & 0x80)
		vram += 0x8000;

	pc_render_gfx_1bpp(bitmap, crtc, vram, palette, 4);
}



/***************************************************************************
  Choose the appropriate video mode
***************************************************************************/

pc_video_update_proc pc_mda_choosevideomode(int *width, int *height, struct crtc6845 *crtc)
{
	pc_video_update_proc proc = NULL;

	switch (mda.mode_control & 0x2a) { /* text and gfx modes */
	case 0x08:
		proc = mda_text_inten;
		*width *= Machine->drv->screen_width / 80;
		break;
	case 0x28:
		proc = mda_text_blink;
		*width *= Machine->drv->screen_width / 80;
		break;
	case 0x0a:
	case 0x2a:
		proc = hercules_gfx;
		*width *= 16;
		break;
    }
	return proc;
}

