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

  vidhrdw/a7800.c

  Routines to control the Atari 7800 video hardware

  TODO:
	precise DMA cycle stealing

	2003-06-23 ericball Kangaroo mode & 320 mode & other stuff

	2002-05-14 kubecj vblank dma stop fix

	2002-05-13 kubecj	fixed 320C mode (displayed 2 pixels instead of one!)
							noticed that Jinks uses 0x02-320D mode
							implemented the mode - completely unsure if good!
							implemented some Maria CTRL variables

	2002-05-12 kubecj added cases for 0x01-160A, 0x05-160B as stated by docs

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

#include "driver.h"
#include "vidhrdw/generic.h"
#include "cpu/m6502/m6502.h"

#include "includes/a7800.h"


#define TRIGGER_HSYNC	64717

#define READ_MEM(x) program_read_byte(x)

/*static unsigned char *ROM; */

/********** Maria ***********/

#define DPPH 0x2c
#define DPPL 0x30
#define CTRL 0x3c

int maria_palette[8][4];
int maria_write_mode;
int maria_scanline;
unsigned int maria_dll;
unsigned int maria_dl;
int maria_holey;
int maria_offset;
int maria_vblank;
int maria_dli;
int maria_dmaon;				/* dma is enabled */
int maria_dodma;				/* doing dma right now */
int maria_wsync;
int maria_backcolor;

int maria_color_kill;
int maria_cwidth;
int maria_bcntl;
int maria_kangaroo;
int maria_rm;

unsigned int maria_charbase;

/* 20030621 ericball define using logical operations */
#define inc_hpos() { hpos = (hpos + 1) & 0x1FF; }
#define inc_hpos_by_2() { hpos = (hpos + 2) & 0x1FF; }

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

  Start the video hardware emulation.

***************************************************************************/
VIDEO_START( a7800 )
{
	int i;

	if (video_start_generic_bitmapped())
		return 1;

	for(i=0; i<8; i++)
	{
		maria_palette[i][0]=0;
		maria_palette[i][1]=0;
		maria_palette[i][2]=0;
		maria_palette[i][3]=0;
	}

	maria_write_mode=0;
	maria_scanline=0;
	maria_dmaon=0;
	maria_vblank=0x80;
	maria_dll=0;
	maria_dodma=0;
	maria_wsync=0;

	maria_color_kill = 0;
	maria_cwidth = 0;
	maria_bcntl = 0;
	maria_kangaroo = 0;
	maria_rm = 0;

	return 0;
}

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

  Stop the video hardware emulation.

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

static void maria_draw_scanline(void)
{
	unsigned int graph_adr,data_addr;
	int width,hpos,pal,mode,ind;
	unsigned int dl;
	int x, d, c, i;
	int ind_bytes;
	UINT16 *scanline;

	/* set up scanline */
	scanline = tmpbitmap->line[maria_scanline];
	for (i = 0; i < 320; i++)
		scanline[i] = maria_backcolor;

	/* Process this DLL entry */
	dl = maria_dl;

	/* Step through DL's */
	while ((READ_MEM(dl + 1) & 0x5F) != 0)
	{

		/* Extended header */
		if (!(READ_MEM(dl+1) & 0x1F))
		{
			graph_adr = (READ_MEM(dl+2) << 8) | READ_MEM(dl);
			width = ((READ_MEM(dl+3) ^ 0xff) & 0x1F) + 1;
			hpos = READ_MEM(dl+4)*2;
			pal = READ_MEM(dl+3) >> 5;
			maria_write_mode = (READ_MEM(dl+1) & 0x80) >> 5;
			ind = READ_MEM(dl+1) & 0x20;
			dl+=5;
		}
		/* Normal header */
		else
		{
			graph_adr = (READ_MEM(dl+2) << 8) | READ_MEM(dl);
			width = ((READ_MEM(dl+1) ^ 0xff) & 0x1F) + 1;
			hpos = READ_MEM(dl+3)*2;
			pal = READ_MEM(dl+1) >> 5;
			ind = 0x00;
			dl+=4;
	 	}

	 	mode = maria_rm | maria_write_mode;

		/*logerror("%x DL: ADR=%x  width=%x  hpos=%x  pal=%x  mode=%x  ind=%x\n",maria_scanline,graph_adr,width,hpos,pal,mode,ind );*/

		for (x=0; x<width; x++) /* 20030621 ericball get graphic data first, then switch (mode) */
		{
			ind_bytes = 1;

			/* Do indirect mode */
			if (ind)
			{
	 			c = READ_MEM(graph_adr + x) & 0xFF;
	 			data_addr= (maria_charbase | c) + (maria_offset << 8);
	 			if( maria_cwidth )
					ind_bytes = 2;
			}
			else
			{
	 			data_addr = graph_adr + x + (maria_offset  << 8);
			}

 			if ( (maria_holey & 0x02) && ((data_addr & 0x9000) == 0x9000))
				continue;
 			if ( (maria_holey & 0x01) && ((data_addr & 0x8800) == 0x8800))
				continue;

			while (ind_bytes > 0)
			{
				ind_bytes--;
				d = READ_MEM(data_addr++);

			 	switch (mode)
				{
					case 0x00:  /* 160A (160x2) */
					case 0x01:  /* 160A (160x2) */
						c = (d & 0xC0) >> 6;
						if (c || maria_kangaroo)
						{
							scanline[hpos + 0] = maria_palette[pal][c];
							scanline[hpos + 1] = maria_palette[pal][c];
						}
						inc_hpos_by_2();

						c = (d & 0x30) >> 4;
						if (c || maria_kangaroo)
						{
							scanline[hpos + 0] = maria_palette[pal][c];
							scanline[hpos + 1] = maria_palette[pal][c];
						}
						inc_hpos_by_2();

						c = (d & 0x0C) >> 2;
						if (c || maria_kangaroo)
						{
							scanline[hpos + 0] = maria_palette[pal][c];
							scanline[hpos + 1] = maria_palette[pal][c];
						}
						inc_hpos_by_2();

						c = (d & 0x03);
						if (c || maria_kangaroo)
						{
							scanline[hpos + 0] = maria_palette[pal][c];
							scanline[hpos + 1] = maria_palette[pal][c];
						}
						inc_hpos_by_2();
					 	break;

					case 0x02: /* 320D used by Jinks! */
						c = pal & 0x04;
						if ( d & 0xC0 || pal & 0x03 || maria_kangaroo )
						{
							scanline[hpos + 0] = maria_palette[c][((d & 0x80) >> 6) | ((pal & 2) >> 1)];
							scanline[hpos + 1] = maria_palette[c][((d & 0x40) >> 5) | ((pal & 1) >> 0)];
						}
						inc_hpos_by_2();

						if ( d & 0x30 || pal & 0x03 || maria_kangaroo )
						{
							scanline[hpos + 0] = maria_palette[c][((d & 0x20) >> 4) | ((pal & 2) >> 1)];
							scanline[hpos + 1] = maria_palette[c][((d & 0x10) >> 3) | ((pal & 1) >> 0)];
						}
						inc_hpos_by_2();

						if ( d & 0x0C || pal & 0x03 || maria_kangaroo )
						{
							scanline[hpos + 0] = maria_palette[c][((d & 0x08) >> 2) | ((pal & 2) >> 1)];
							scanline[hpos + 1] = maria_palette[c][((d & 0x04) >> 1) | ((pal & 1) >> 0)];
						}
						inc_hpos_by_2();

						if ( d & 0x03 || pal & 0x03 || maria_kangaroo )
						{
							scanline[hpos + 0] = maria_palette[c][((d & 0x02) << 0) | ((pal & 2) >> 1)];
							scanline[hpos + 1] = maria_palette[c][((d & 0x01) << 1) | ((pal & 1) >> 0)];
						}
						inc_hpos_by_2();

					 	break;

					case 0x03:  /* MODE 320A */
						if (d & 0xC0 || maria_kangaroo)
						{
							scanline[hpos + 0] = maria_palette[pal][(d & 0x80) >> 6];
							scanline[hpos + 1] = maria_palette[pal][(d & 0x40) >> 5];
						}
						inc_hpos_by_2();

						if ( d & 0x30 || maria_kangaroo)
						{
							scanline[hpos + 0] = maria_palette[pal][(d & 0x20) >> 4];
							scanline[hpos + 1] = maria_palette[pal][(d & 0x10) >> 3];
						}
						inc_hpos_by_2();

						if (d & 0x0C || maria_kangaroo)
						{
							scanline[hpos + 0] = maria_palette[pal][(d & 0x08) >> 2];
							scanline[hpos + 1] = maria_palette[pal][(d & 0x04) >> 1];
						}
						inc_hpos_by_2();

						if (d & 0x03 || maria_kangaroo)
						{
							scanline[hpos + 0] = maria_palette[pal][(d & 0x02)];
							scanline[hpos + 1] = maria_palette[pal][(d & 0x01) << 1];
						}
						inc_hpos_by_2();
					 	break;

					case 0x04:  /* 160B (160x4) */
					case 0x05:  /* 160B (160x4) */
						c = (d & 0xC0) >> 6;
						if (c || maria_kangaroo)
						{
							scanline[hpos + 0] = maria_palette[(pal & 0x04) | ((d & 0x0C) >> 2)][c];
							scanline[hpos + 1] = maria_palette[(pal & 0x04) | ((d & 0x0C) >> 2)][c];
						}
						inc_hpos_by_2();

						c = (d & 0x30) >> 4;
						if (c || maria_kangaroo)
						{
							scanline[hpos + 0] = maria_palette[(pal & 0x04) | (d & 0x03)][c];
							scanline[hpos + 1] = maria_palette[(pal & 0x04) | (d & 0x03)][c];
						}
						inc_hpos_by_2();
					 	break;

				 	case 0x06:  /* MODE 320B */
						if (d & 0xCC || maria_kangaroo)
						{
							scanline[hpos + 0] = maria_palette[pal][((d & 0x80) >> 6) | ((d & 0x08) >> 3)];
							scanline[hpos + 1] = maria_palette[pal][((d & 0x40) >> 5) | ((d & 0x04) >> 2)];
						}
						inc_hpos_by_2();

						if ( d & 0x33 || maria_kangaroo)
						{
							scanline[hpos + 0] = maria_palette[pal][((d & 0x20) >> 4) | ((d & 0x02) >> 1)];
							scanline[hpos + 1] = maria_palette[pal][((d & 0x10) >> 3) | (d & 0x01)];
						}
						inc_hpos_by_2();
						break;

					case 0x07: /* (320C mode) */
						if (d & 0xC0 || maria_kangaroo)
						{
							scanline[hpos + 0] = maria_palette[(pal & 0x04) | ((d & 0x0C) >> 2)][(d & 0x80) >> 6];
							scanline[hpos + 1] = maria_palette[(pal & 0x04) | ((d & 0x0C) >> 2)][(d & 0x40) >> 5];
						}
						inc_hpos_by_2();

						if ( d & 0x30 || maria_kangaroo)
						{
							scanline[hpos + 0] = maria_palette[(pal & 0x04) | (d & 0x03)][(d & 0x20) >> 4];
							scanline[hpos + 1] = maria_palette[(pal & 0x04) | (d & 0x03)][(d & 0x10) >> 3];
						}
						inc_hpos_by_2();
						break;

					}	/* endswitch (mode) */
				}	/* endwhile (ind_bytes > 0)*/
		 	}	/* endfor (x=0; x<width; x++) */
	}	/* endwhile (READ_MEM(dl + 1) != 0) */
}


void a7800_interrupt(void)
{
	int frame_scanline;
	UINT8 *ROM = memory_region(REGION_CPU1);

	maria_scanline++;

	/* why + 1? */
	frame_scanline = maria_scanline % ( a7800_lines + 1 );

	if( frame_scanline == 1 )
	{
		/*logerror( "frame beg\n" );*/
	}

	if( maria_wsync )
	{
		cpu_trigger( TRIGGER_HSYNC );
		maria_wsync = 0;
	}

	if( frame_scanline == 16 )
	{
		/* end of vblank */

		maria_vblank=0;
		if( maria_dmaon || maria_dodma )
		{
			maria_dodma = 1;	/* if dma allowed, start it */

			maria_dll = (ROM[DPPH] << 8) | ROM[DPPL];
			maria_dl = (READ_MEM(maria_dll+1) << 8) | READ_MEM(maria_dll+2);
			maria_offset = READ_MEM(maria_dll) & 0x0f;
			maria_holey = (READ_MEM(maria_dll) & 0x60) >> 5;
			maria_dli = READ_MEM(maria_dll) & 0x80;
			/*	logerror("DLL=%x\n",maria_dll); */
			/*	logerror("DLL: DL = %x  dllctrl = %x\n",maria_dl,ROM[maria_dll]); */
		}

		/*logerror( "vblank end on line %d\n", frame_scanline );*/
	}

	/*	moved start of vblank up (to prevent dma/dli happen on line -4)
		this fix made PR Baseball happy
		Kung-Fu Master looks worse
		don't know about others yet */
	if( frame_scanline == ( a7800_lines - 4 ) )
	{
		/* vblank starts 4 scanlines before end of screen */

		maria_vblank = 0x80;

		/* fixed 2002/05/14 kubecj
				when going vblank, dma must be stopped
				otherwise system tries to read past end of dll
				causing false dlis to occur, mainly causing wild
				screen flickering

				games fixed:
				Ace of Aces
				Mean 18
				Ninja Golf (end of levels)
				Choplifter
				Impossible Mission
				Jinks
		*/

		maria_dodma = 0;
		/*logerror( "vblank on line %d\n\n", frame_scanline );*/
	}


	if( ( frame_scanline > 15 ) && maria_dodma )
	{
		if (maria_scanline < ( a7800_lines - 4 ) )
			maria_draw_scanline();

		if( maria_offset == 0 )
		{
			maria_dll+=3;
			maria_dl = (READ_MEM(maria_dll+1) << 8) | READ_MEM(maria_dll+2);
			maria_offset = READ_MEM(maria_dll) & 0x0f;
			maria_holey = (READ_MEM(maria_dll) & 0x60) >> 5;
			maria_dli = READ_MEM(maria_dll) & 0x80;
		}
		else
		{
			maria_offset--;
		}
	}

	if( maria_dli )
	{
		/*logerror( "dli on line %d [%02X] [%02X] [%02X]\n", frame_scanline, ROM[0x7E], ROM[0x7C], ROM[0x7D] );*/
	}

	if( maria_dli )
	{
		maria_dli = 0;
		cpunum_set_input_line(0, INPUT_LINE_NMI, PULSE_LINE);
	}

}

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

  Refresh the video screen

***************************************************************************/
/* This routine is called at the start of vblank to refresh the screen */
VIDEO_UPDATE( a7800 )
{
	maria_scanline=0;
	video_update_generic_bitmapped(bitmap, cliprect, do_skip);
}


/****** MARIA ***************************************/

 READ8_HANDLER( a7800_MARIA_r )
{
	UINT8 *ROM = memory_region(REGION_CPU1);
	switch (offset)
	{
		case 0x08:
			return maria_vblank;

		default:
			logerror("undefined MARIA read %x\n",offset);
			return ROM[0x20 + offset];
	}
}

WRITE8_HANDLER( a7800_MARIA_w )
{
	UINT8 *ROM = memory_region(REGION_CPU1);
	switch (offset)
	{
		case 0x00:
			maria_backcolor = Machine->pens[data];
			/* 20030621 ericball added maria_palette[pal][0] to make kanagroo mode easier */
			maria_palette[0][0]=maria_backcolor;
			maria_palette[1][0]=maria_backcolor;
			maria_palette[2][0]=maria_backcolor;
			maria_palette[3][0]=maria_backcolor;
			maria_palette[4][0]=maria_backcolor;
			maria_palette[5][0]=maria_backcolor;
			maria_palette[6][0]=maria_backcolor;
			maria_palette[7][0]=maria_backcolor;
			break;
		case 0x01:
			maria_palette[0][1] = Machine->pens[data];
			break;
		case 0x02:
			maria_palette[0][2] = Machine->pens[data];
			break;
		case 0x03:
			maria_palette[0][3] = Machine->pens[data];
			break;
		case 0x04:
			cpu_spinuntil_trigger(TRIGGER_HSYNC);
			maria_wsync=1;
			break;

		case 0x05:
			maria_palette[1][1] = Machine->pens[data];
			break;
		case 0x06:
			maria_palette[1][2] = Machine->pens[data];
			break;
		case 0x07:
			maria_palette[1][3] = Machine->pens[data];
			break;

		case 0x09:
			maria_palette[2][1] = Machine->pens[data];
			break;
		case 0x0A:
			maria_palette[2][2] = Machine->pens[data];
			break;
		case 0x0B:
			maria_palette[2][3] = Machine->pens[data];
			break;

		case 0x0D:
			maria_palette[3][1] = Machine->pens[data];
			break;
		case 0x0E:
			maria_palette[3][2] = Machine->pens[data];
			break;
		case 0x0F:
			maria_palette[3][3] = Machine->pens[data];
			break;

		case 0x11:
			maria_palette[4][1] = Machine->pens[data];
			break;
		case 0x12:
			maria_palette[4][2] = Machine->pens[data];
			break;
		case 0x13:
			maria_palette[4][3] = Machine->pens[data];
			break;
		case 0x14:
			maria_charbase = (data << 8);
			break;
		case 0x15:
			maria_palette[5][1] = Machine->pens[data];
			break;
		case 0x16:
			maria_palette[5][2] = Machine->pens[data];
			break;
		case 0x17:
			maria_palette[5][3] = Machine->pens[data];
			break;

		case 0x19:
			maria_palette[6][1] = Machine->pens[data];
			break;
		case 0x1A:
			maria_palette[6][2] = Machine->pens[data];
			break;
		case 0x1B:
			maria_palette[6][3] = Machine->pens[data];
			break;

		case 0x1C:
			/*logerror("MARIA CTRL=%x\n",data);*/
			maria_color_kill = data & 0x80;
			if ((data & 0x60) == 0x40)
				maria_dmaon = 1;
			else
				maria_dmaon = maria_dodma = 0;

			maria_cwidth = data & 0x10;
			maria_bcntl = data & 0x08;
			maria_kangaroo = data & 0x04;
			maria_rm = data & 0x03;

			/*logerror( "MARIA CTRL: CK:%d DMA:%d CW:%d BC:%d KM:%d RM:%d\n",
					maria_color_kill ? 1 : 0,
					( data & 0x60 ) >> 5,
					maria_cwidth ? 1 : 0,
					maria_bcntl ? 1 : 0,
					maria_kangaroo ? 1 : 0,
					maria_rm );*/

			break;
		case 0x1D:
			maria_palette[7][1] = Machine->pens[data];
			break;
		case 0x1E:
			maria_palette[7][2] = Machine->pens[data];
			break;
		case 0x1F:
			maria_palette[7][3] = Machine->pens[data];
			break;
	}
	ROM[ 0x20 + offset ] = data;
}

