/*
 * vector.c: Atari DVG and AVG simulators
 *
 * Copyright 1991, 1992, 1996 Eric Smith
 * Modified for the MAME project 1997 by Brad Oliver & Bernd Wiebelt
 *  
 */

#include "driver.h"
#include "vector.h"

int dvg = 0;

int x_res;	/* X-resolution of the display device */
int y_res;	/* Y-resolution of the display device */
int portrait;   /* for Tempest and Major Havoc */

#define BASE 16384L	/* Precision of vector instructions */

#ifdef VG_DEBUG
int trace_vgo = 0;
int vg_step = 0; /* single step the vector generator */
int vg_print = 1;
unsigned long last_vgo_cyc=0;
unsigned long vgo_count=0;
#endif /* VG_DEBUG */

int vg_busy = 0;
unsigned long vg_done_cyc; /* cycle after which VG will be done */

unsigned char *vectorram; /* LBO 062797 */

#define MAXSTACK 4

#define VCTR 0
#define HALT 1
#define SVEC 2
#define STAT 3
#define CNTR 4
#define JSRL 5
#define RTSL 6
#define JMPL 7
#define SCAL 8

#define DVCTR 0x01
#define DLABS 0x0a
#define DHALT 0x0b
#define DJSRL 0x0c
#define DRTSL 0x0d
#define DJMPL 0x0e
#define DSVEC 0x0f

#define twos_comp_val(num,bits) ((num&(1<<(bits-1)))?(num|~((1<<bits)-1)):(num&((1<<bits)-1)))

char *avg_mnem[] = { "vctr", "halt", "svec", "stat", "cntr", "jsrl", "rtsl",
		 "jmpl", "scal" };

char *dvg_mnem[] = { "????", "vct1", "vct2", "vct3",
		     "vct4", "vct5", "vct6", "vct7",
		     "vct8", "vct9", "labs", "halt",
		     "jsrl", "rtsl", "jmpl", "svec" };

#define map_addr(n) (((n)<<1)) /* LBO 062797 */
#define memrdwd(offset,PC,cyc) ((vectorram[offset]) | (vectorram[offset+1]<<8)) /* LBO 062797 */

#define max(x,y) (((x)>(y))?(x):(y))

static void vector_timer (long deltax, long deltay)
{
	deltax = labs (deltax);
	deltay = labs (deltay);
	vg_done_cyc -= max (deltax, deltay) >> 17; /* LBO 062797 */
}


static void dvg_vector_timer (int scale)
{
	vg_done_cyc -= 4 << scale; /* LBO 062797 */
}


static void dvg_draw_vector_list (void)
{
	int pc;
	int sp;
	int stack [MAXSTACK];

	int scale;
	int statz;

	int currentx, currenty;

	int done = 0;

	int firstwd;
	int secondwd = 0; /* Initialize to tease the compiler */
	int opcode;

	long x, y;
	int z, temp;
	int a;

	long deltax, deltay;
	
	pc = 0;
	sp = 0;
	scale = 0;
	statz = 0;

#ifdef VG_DEBUG
	open_page (&x_res,&y_res,&portrait,vg_step);
#else
	open_page (&x_res,&y_res,&portrait,0);
#endif
	
	currentx=511*8192;
	currenty=1023*8192;

  	while (!done)
	{  
		vg_done_cyc -= 8; /* LBO 062797 */
#ifdef VG_DEBUG
		if (vg_step)
		{
	  		if (errorlog)
				fprintf (errorlog,"Current beam position: (%d, %d)\n",
			currentx, currenty);
	  		getchar();
		}
#endif

		firstwd = memrdwd (map_addr (pc), 0, 0);
		opcode = firstwd >> 12;
#ifdef VG_DEBUG
		if (vg_print && errorlog)
			fprintf (errorlog,"%4x: %4x ", map_addr (pc), firstwd);
#endif
		pc++;
		if ((opcode >= 0 /* DVCTR */) && (opcode <= DLABS))
		{
			secondwd = memrdwd (map_addr (pc), 0, 0);
			pc++;
#ifdef VG_DEBUG
			if (vg_print && errorlog)
				fprintf (errorlog,"%4x  ", secondwd);
#endif
		}
#ifdef VG_DEBUG
		else
		if (vg_print && errorlog)
			fprintf (errorlog,"whatever Brad wanted to put here ;-) \n");
#endif

#ifdef VG_DEBUG
		if (vg_print && errorlog)
			fprintf (errorlog,"%s ", dvg_mnem [opcode]);
#endif

		switch (opcode)
		{
			case 0:
#ifdef DVG_OP_0_ERR
	 			if (errorlog) fprintf (errorlog,"Error: DVG opcode 0!  Addr %4x Instr %4x %4x\n", map_addr (pc-2), firstwd, secondwd);
				done = 1;
				break;
#endif
			case 1:
			case 2:
			case 3:
			case 4:
			case 5:
			case 6:
			case 7:
			case 8:
			case 9:
	  			y = firstwd & 0x03ff;
				if (firstwd & 0x400)
					y=-y;
				x = secondwd & 0x3ff;
				if (secondwd & 0x400)
					x=-x;
				z = secondwd >> 12;
#ifdef VG_DEBUG
				if (vg_print && errorlog)
					fprintf (errorlog,"(%d,%d) z: %d scal: %d", x, y, z, opcode);
#endif
	  			temp = ((scale + opcode) & 0x0f);
	  			if (temp > 9)
					temp = -1;
	  			deltax = (x << 21) >> (30-temp);
				deltay = (y << 21) >> (30-temp);
	  			currentx += deltax;
				currenty -= deltay;
				dvg_vector_timer (temp);
				draw_to (currentx >> 1, currenty >> 1, 7, z);
				break;

			case DLABS:
				x = twos_comp_val (secondwd, 12);
				y = twos_comp_val (firstwd, 12);
	  			scale = (secondwd >> 12);
				currentx = x;
				currenty = (930-y);
#ifdef VG_DEBUG
				if (vg_print && errorlog)
					fprintf (errorlog,"(%d,%d) scal: %d", x, y, secondwd >> 12);
#endif
				break;

			case DHALT:
#ifdef VG_DEBUG
				if ((vg_print) && ((firstwd & 0x0fff) != 0) &&
					(errorlog))
	      				fprintf (errorlog,"(%d?)", firstwd & 0x0fff);
#endif
				done = 1;
				break;

			case DJSRL:
				a = firstwd & 0x0fff;
#ifdef VG_DEBUG
				if (vg_print && errorlog)
					fprintf (errorlog,"%4x", map_addr(a));
#endif
				stack [sp] = pc;
				if (sp == (MAXSTACK - 1))
	    			{
					if (errorlog) fprintf (errorlog,"\n*** Vector generator stack overflow! ***\n");
					done = 1;
					sp = 0;
				}
				else
					sp++;
				pc = a;
				break;
	
			case DRTSL:
#ifdef VG_DEBUG
				if ((vg_print) && ((firstwd & 0x0fff) != 0) &&
					(errorlog))
					 fprintf (errorlog,"(%d?)", firstwd & 0x0fff);
#endif
				if (sp == 0)
	    			{
					if (errorlog) fprintf (errorlog,"\n*** Vector generator stack underflow! ***\n");
					done = 1;
					sp = MAXSTACK - 1;
				}
				else
					sp--;
				pc = stack [sp];
				break;

			case DJMPL:
				a = firstwd & 0x0fff;
#ifdef VG_DEBUG
				if (vg_print && errorlog)
					fprintf (errorlog,"%4x", map_addr(a));
#endif
				pc = a;
				break;
	
			case DSVEC:
				y = firstwd & 0x0300;
				if (firstwd & 0x0400)
					y = -y;
				x = (firstwd & 0x03) << 8;
				if (firstwd & 0x04)
					x = -x;
				z = (firstwd >> 4) & 0x0f;
#ifdef VG_DEBUG
				if (vg_print && errorlog)
	      				fprintf (errorlog,"(%d,%d) z: %d scal: %d", x, y, z, temp);
#endif
				temp = 2 + ((firstwd >> 2) & 0x02) + ((firstwd >>11) & 0x01);
	  			temp = ((scale + temp) & 0x0f);
				if (temp > 9)
					temp = -1;
				deltax = (x << 21) >> (30-temp);
				deltay = (y << 21) >> (30-temp);
	  			currentx += deltax;
				currenty -= deltay;
				dvg_vector_timer (temp);
				draw_to (currentx>>1, currenty>>1, 7, z);
				break;

			default:
				if (errorlog)
					fprintf (errorlog,"internal error\n");
				done = 1;
		}
#ifdef VG_DEBUG
      		if (vg_print && errorlog)
			fprintf (errorlog,"\n");
#endif
	}
	close_page ();
}


static void avg_draw_vector_list (void) {

	int pc;
	int sp;
	int stack [MAXSTACK];

	int x_init_scale, y_init_scale;
	int xscale, yscale;

	int statz;
	int color;

	int currentx, currenty;
	int xcenter, ycenter;
	int done = 0;

	int firstwd, secondwd;
	int opcode;

	int x, y, z, b, l, d, a;

	int deltax, deltay;

#if 0
	if (!cont)
#endif
	{
		pc = 0;
		sp = 0;
		statz = 0;
		color = 0;

		firstwd = memrdwd (map_addr (pc), 0, 0);
		secondwd = memrdwd (map_addr (pc+1), 0, 0);
		if ((firstwd == 0) && (secondwd == 0)) {
			if (errorlog) fprintf (errorlog,"VGO with zeroed vector memory\n");
			return;
			}
	}

#ifdef VG_DEBUG
	open_page (&x_res,&y_res,&portrait,vg_step);
#else
	open_page (&x_res,&y_res,&portrait,0);
#endif

	if (portrait)
	{
		x_init_scale = (x_res * BASE) / 580;
		y_init_scale = (y_res * BASE) / 520;	
		xcenter = 290 * x_init_scale;
		ycenter = 260 * y_init_scale;
	}
	else
	{
		x_init_scale = (x_res * BASE) / 520;
		y_init_scale = (y_res * BASE) / 460;	
		xcenter = 260 * x_init_scale;
		ycenter = 230 * y_init_scale;
	}
	xscale = x_init_scale;
	yscale = y_init_scale;
	currentx = xcenter;
	currenty = xcenter;

	while (!done) {
		vg_done_cyc -= 8; /* LBO 062797 */
#ifdef VG_DEBUG
		if (vg_step)
			getchar();
#endif
		firstwd = memrdwd (map_addr (pc), 0, 0);
		opcode = firstwd >> 13;
#ifdef VG_DEBUG
		if (vg_print)
			if (errorlog) fprintf (errorlog,"%4x: %4x ", map_addr (pc), firstwd);
#endif
		pc++;
		if (opcode == VCTR) {
			secondwd = memrdwd (map_addr (pc), 0, 0);
			pc++;
#ifdef VG_DEBUG
			if (vg_print)
				if (errorlog) fprintf (errorlog,"%4x  ", secondwd);
#endif
			}
#ifdef VG_DEBUG
		else
			if (vg_print)
				if (errorlog) fprintf (errorlog,"      ");
#endif

		if ((opcode == STAT) && ((firstwd & 0x1000) != 0))
			opcode = SCAL;

#ifdef VG_DEBUG
		if (vg_print)
			if (errorlog) fprintf (errorlog,"%s ", avg_mnem [opcode]);
#endif

		switch (opcode) {
			case VCTR:
				x = twos_comp_val (secondwd,13);
				y = twos_comp_val (firstwd,13);
				z = 2 * (secondwd >> 13);
#ifdef VG_DEBUG
				if (vg_print)
					if (errorlog) fprintf (errorlog,"%d,%d,", x, y);
#endif
				if (z == 0) {
#ifdef VG_DEBUG
					if (vg_print)
						if (errorlog) fprintf (errorlog,"blank");
#endif
					}
				else if (z == 2) {
					z = statz;
#ifdef VG_DEBUG
					if (vg_print)
						if (errorlog) fprintf (errorlog,"stat (%d)", z);
#endif
					}
#ifdef VG_DEBUG
				else if (vg_print)
					if (errorlog) fprintf (errorlog,"%d", z);
#endif
				deltax = x * xscale; deltay = y * yscale;
				currentx += deltax;
				currenty -= deltay;
				vector_timer (deltax, deltay);
				draw_to (currentx>>14, currenty>>14, color, z);
				break;
	
			case SVEC:
				x = twos_comp_val (firstwd, 5) << 1;
				y = twos_comp_val (firstwd >> 8, 5) << 1;
				z = 2 * ((firstwd >> 5) & 7);
#ifdef VG_DEBUG
				if (vg_print)
					if (errorlog) fprintf (errorlog,"%d,%d,", x, y);
#endif
				if (z == 0) {
#ifdef VG_DEBUG
					if (vg_print)
						if (errorlog) fprintf (errorlog,"blank");
#endif
					}
				else if (z == 2) {
					z = statz;
#ifdef VG_DEBUG
					if (vg_print)
						if (errorlog) fprintf (errorlog,"stat");
#endif
					}
#ifdef VG_DEBUG
				else if (vg_print)
					if (errorlog) fprintf (errorlog,"%d", z);
#endif
				deltax = x * xscale; deltay = y * yscale;
				currentx += deltax;
				currenty -= deltay;
				vector_timer (labs (deltax), labs (deltay));
				draw_to (currentx>>14, currenty>>14, color, z);
				break;
	
			case STAT:
				color = firstwd & 0x0f;
				statz = (firstwd >> 4) & 0x0f;
#ifdef VG_DEBUG
				if (vg_print)
					if (errorlog) fprintf (errorlog,"z: %d color: %d", statz, color);
#endif
				/* should do e, h, i flags here! */
				break;
      
			case SCAL:
				b = (firstwd >> 8) & 0x07;
				l = firstwd & 0xff;
				xscale = (x_init_scale - (l * x_init_scale/256)) >> b;
				yscale = (y_init_scale - (l * y_init_scale/256)) >> b;

#ifdef VG_DEBUG
				if (vg_print) {
					if (errorlog) fprintf (errorlog,"bin: %d, lin: ", b);
					if (l > 0x80)
						if (errorlog) fprintf (errorlog,"(%d?)", l);
					else
						if (errorlog) fprintf (errorlog,"%d", l);
					if (errorlog) fprintf (errorlog," scale: %f", (scale/(float)(FIXBASE));
					}
#endif
				break;
	
			case CNTR:
				d = firstwd & 0xff;
#ifdef VG_DEBUG
				if (vg_print) {
					if (d != 0x40)
						if (errorlog) fprintf (errorlog,"%d", d);
					}
#endif
				currentx = xcenter;
				currenty = ycenter;
				break;
	
			case RTSL:
#ifdef VG_DEBUG
				if (vg_print)
					if ((firstwd & 0x1fff) != 0)
						if (errorlog) fprintf (errorlog,"(%d?)", firstwd & 0x1fff);
#endif
				if (sp == 0) {
					if (errorlog) fprintf (errorlog,"\n*** Vector generator stack underflow! ***\n");
					done = 1;
					sp = MAXSTACK - 1;
					}
				else
					sp--;
				pc = stack [sp];
				break;

			case HALT:
#ifdef VG_DEBUG
				if (vg_print)
					if ((firstwd & 0x1fff) != 0)
						if (errorlog) fprintf (errorlog,"(%d?)", firstwd & 0x1fff);
#endif
				done = 1;
				break;

			case JMPL:
				a = firstwd & 0x1fff;
#ifdef VG_DEBUG
				if (vg_print)
					if (errorlog) fprintf (errorlog,"%4x", map_addr(a));
#endif
				/* if a = 0x0000, treat as HALT */
				if (a == 0x0000)
					done = 1;
				else
					pc = a;
				break;
	
			case JSRL:
				a = firstwd & 0x1fff;
#ifdef VG_DEBUG
				if (vg_print)
					if (errorlog) fprintf (errorlog,"%4x", map_addr(a));
#endif
				/* if a = 0x0000, treat as HALT */
				if (a == 0x0000)
					done = 1;
				else {
					stack [sp] = pc;
					if (sp == (MAXSTACK - 1)) {
						if (errorlog) fprintf (errorlog,"\n*** Vector generator stack overflow! ***\n");
						done = 1;
						sp = 0;
						}
					else
						sp++;
					pc = a;
					}
				break;
	
			default:
				if (errorlog) fprintf (errorlog,"internal error\n");
			}
#ifdef VG_DEBUG
		if (vg_print)
			if (errorlog) fprintf (errorlog,"\n");
#endif
		}

	close_page ();
	}

int vg_done (unsigned long cyc)
{
  if (vg_busy && (cyc < vg_done_cyc)) /* LBO 062797 */
    vg_busy = 0;

  return (! vg_busy);
}

void vg_go (int offset, int data)
{
 unsigned long	cyc;

 cyc = cpu_geticount ();
  vg_busy = 1;
  vg_done_cyc = cyc - 8; /* LBO 062797 */
#ifdef VG_DEBUG
  vgo_count++;
  if (trace_vgo)
    if (errorlog) fprintf (errorlog,"VGO #%d at cycle %d, delta %d\n", vgo_count, cyc, last_vgo_cyc-cyc);
  last_vgo_cyc = cyc;
#endif
  if (dvg)
    dvg_draw_vector_list ();
  else
    avg_draw_vector_list ();
}

void vg_reset (int offset, int data)
{
 unsigned long	cyc;

 cyc = cpu_geticount ();
  vg_busy = 0;
#ifdef VG_DEBUG
  if (trace_vgo)
    if (errorlog) fprintf (errorlog,"vector generator reset @%04x\n", cpu_getpc());
#endif
}

int vg_init (int len, int usingDvg)
{
	if (usingDvg) dvg = 1;
	else dvg = 0;
	return 0;
}

void vg_stop (void)
{
}