path: root/source/dsp4emu.c

/*******************************************************************************
  Snes9x - Portable Super Nintendo Entertainment System (TM) emulator.

  (c) Copyright 1996 - 2002 Gary Henderson (gary.henderson@ntlworld.com) and
                            Jerremy Koot (jkoot@snes9x.com)

  (c) Copyright 2001 - 2004 John Weidman (jweidman@slip.net)

  (c) Copyright 2002 - 2004 Brad Jorsch (anomie@users.sourceforge.net),
                            funkyass (funkyass@spam.shaw.ca),
                            Joel Yliluoma (http://iki.fi/bisqwit/)
                            Kris Bleakley (codeviolation@hotmail.com),
                            Matthew Kendora,
                            Nach (n-a-c-h@users.sourceforge.net),
                            Peter Bortas (peter@bortas.org) and
                            zones (kasumitokoduck@yahoo.com)

  C4 x86 assembler and some C emulation code
  (c) Copyright 2000 - 2003 zsKnight (zsknight@zsnes.com),
                            _Demo_ (_demo_@zsnes.com), and Nach

  C4 C++ code
  (c) Copyright 2003 Brad Jorsch

  DSP-1 emulator code
  (c) Copyright 1998 - 2004 Ivar (ivar@snes9x.com), _Demo_, Gary Henderson,
                            John Weidman, neviksti (neviksti@hotmail.com),
                            Kris Bleakley, Andreas Naive

  DSP-2 emulator code
  (c) Copyright 2003 Kris Bleakley, John Weidman, neviksti, Matthew Kendora, and
                     Lord Nightmare (lord_nightmare@users.sourceforge.net

  OBC1 emulator code
  (c) Copyright 2001 - 2004 zsKnight, pagefault (pagefault@zsnes.com) and
                            Kris Bleakley
  Ported from x86 assembler to C by sanmaiwashi

  SPC7110 and RTC C++ emulator code
  (c) Copyright 2002 Matthew Kendora with research by
                     zsKnight, John Weidman, and Dark Force

  S-DD1 C emulator code
  (c) Copyright 2003 Brad Jorsch with research by
                     Andreas Naive and John Weidman

  S-RTC C emulator code
  (c) Copyright 2001 John Weidman

  ST010 C++ emulator code
  (c) Copyright 2003 Feather, Kris Bleakley, John Weidman and Matthew Kendora

  Super FX x86 assembler emulator code
  (c) Copyright 1998 - 2003 zsKnight, _Demo_, and pagefault

  Super FX C emulator code
  (c) Copyright 1997 - 1999 Ivar, Gary Henderson and John Weidman


  SH assembler code partly based on x86 assembler code
  (c) Copyright 2002 - 2004 Marcus Comstedt (marcus@mc.pp.se)


  Specific ports contains the works of other authors. See headers in
  individual files.

  Snes9x homepage: http://www.snes9x.com

  Permission to use, copy, modify and distribute Snes9x in both binary and
  source form, for non-commercial purposes, is hereby granted without fee,
  providing that this license information and copyright notice appear with
  all copies and any derived work.

  This software is provided 'as-is', without any express or implied
  warranty. In no event shall the authors be held liable for any damages
  arising from the use of this software.

  Snes9x is freeware for PERSONAL USE only. Commercial users should
  seek permission of the copyright holders first. Commercial use includes
  charging money for Snes9x or software derived from Snes9x.

  The copyright holders request that bug fixes and improvements to the code
  should be forwarded to them so everyone can benefit from the modifications
  in future versions.

  Super NES and Super Nintendo Entertainment System are trademarks of
  Nintendo Co., Limited and its subsidiary companies.
*******************************************************************************/

#include "dsp4.h"
#include "memmap.h"

#define DSP4_READ_WORD(x) \
   READ_WORD(DSP4.parameters+x)

#define DSP4_WRITE_WORD(x,d) \
   WRITE_WORD(DSP4.output+x,d);

// used to wait for dsp i/o
#define DSP4_WAIT(x) \
   DSP4_Logic = x; return;

//////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////

int DSP4_Multiply(int16_t Multiplicand, int16_t Multiplier)
{
   return Multiplicand * Multiplier;
}

int16_t DSP4_UnknownOP11(int16_t A, int16_t B, int16_t C, int16_t D)
{
   return ((A * 0x0155 >>  2) & 0xf000) | ((B * 0x0155 >>  6) & 0x0f00) |
          ((C * 0x0155 >> 10) & 0x00f0) | ((D * 0x0155 >> 14) & 0x000f);
}

//////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////

void DSP4_Op06(bool size, bool msb)
{
   // save post-oam table data for future retrieval
   op06_OAM[op06_index] |= (msb << (op06_offset + 0));
   op06_OAM[op06_index] |= (size << (op06_offset + 1));
   op06_offset += 2;

   if (op06_offset == 8)
   {
      // move to next byte in buffer
      op06_offset = 0;
      op06_index++;
   }
}

#if OP==0x0001
#define PRINT
#endif

void DSP4_Op01()
{
   uint16_t command;

   DSP4.waiting4command = false;

   // op flow control
   switch (DSP4_Logic)
   {
   case 1:
      goto resume1;
      break;
   case 2:
      goto resume2;
      break;
   }

   ////////////////////////////////////////////////////
   // process initial inputs

   // sort inputs
   // 0x00 = DSP4_READ_WORD(0x00);
   project_focaly = DSP4_READ_WORD(0x02);
   raster = DSP4_READ_WORD(0x04);
   viewport_top = DSP4_READ_WORD(0x06);
   project_y = DSP4_READ_WORD(0x08);
   viewport_bottom = DSP4_READ_WORD(0x0a);
   project_x1low = DSP4_READ_WORD(0x0c);
   project_focalx = DSP4_READ_WORD(0x0e);
   project_centerx = DSP4_READ_WORD(0x10);
   project_ptr = DSP4_READ_WORD(0x12);
   // (envelope?) 0xc0 = DSP4_READ_WORD(0x14);
   project_pitchylow = DSP4_READ_WORD(0x16);
   project_pitchy = DSP4_READ_WORD(0x18);
   project_pitchxlow = DSP4_READ_WORD(0x1a);
   project_pitchx = DSP4_READ_WORD(0x1c);
   far_plane = DSP4_READ_WORD(0x1e);
   // ? = DSP4_READ_WORD(0x20);
   project_y1low = DSP4_READ_WORD(0x22);

   // pre-compute
   view_plane = PLANE_START;

   // find starting projection points
   project_x1 = project_focalx;
   project_y -= viewport_bottom;
   project_x = project_centerx + project_x1;

   // multi-op storage
   multi_index1 = 0;
   multi_index2 = 0;

   // debug
   block = 0;

   ////////////////////////////////////////////////////
   // command check

   do
   {
      // scan next command
      DSP4.in_count = 2;

DSP4_WAIT(1) resume1:

      // inspect input
      command = DSP4_READ_WORD(0);

      // check for termination
      if (command == 0x8000) break;

      // already have 2 bytes in queue
      DSP4.in_index = 2;
      DSP4.in_count = 8;

      DSP4_WAIT(2)

      ////////////////////////////////////////////////////
      // process one iteration of projection

      // inspect inputs
      int16_t plane;

      int16_t index, lcv;
      int16_t py_dy, px_dx;
      int16_t y_out, x_out;

resume2:
      plane = DSP4_READ_WORD(0);
      py_dy = 0;
      px_dx = 0;

      // ignore invalid data
      if ((uint16_t) plane == 0x8001) continue;

      // one-time init
      if (far_plane)
      {
         // setup final parameters
         project_focalx += plane;
         project_x1 = project_focalx;
         project_y1 = project_focaly;
         plane = far_plane;
         far_plane = 0;
      }

      // use proportional triangles to project new coords
      project_x2 = project_focalx * plane / view_plane;
      project_y2 = project_focaly * plane / view_plane;

      // quadratic regression (rough)
      if (project_focaly >= -0x0f)
         py_dy = (int16_t)(project_focaly * project_focaly * -0.20533553
                         - 1.08330005 * project_focaly - 69.61094639);
      else
         py_dy = (int16_t)(project_focaly * project_focaly * -0.000657035759
                         - 1.07629051 * project_focaly - 65.69315963);

      // approximate # of raster lines
      segments = abs(project_y2 - project_y1);

      // prevent overdraw
      if (project_y2 >= raster) segments = 0;
      else raster = project_y2;

      // don't draw outside the window
      if (project_y2 < viewport_top) segments = 0;

      // project new positions
      if (segments > 0)
      {
         // interpolate between projected points
         px_dx = ((project_x2 - project_x1) << 8) / segments;
      }

      // debug
      ++block;
#ifdef PRINT
      printf("(line %d) Op01 check %02X, plane %04X, focal_y %04X, y2 %04X\n", c,
             (uint16_t)segments, (uint16_t)(plane), (uint16_t)project_focaly, (uint16_t)project_y2);
#endif

      // prepare output
      DSP4.out_count = 8 + 2 + 6 * segments;

      // pre-block data
      DSP4_WRITE_WORD(0, project_focalx);
      DSP4_WRITE_WORD(2, project_x2);
      DSP4_WRITE_WORD(4, project_focaly);
      DSP4_WRITE_WORD(6, project_y2);
      DSP4_WRITE_WORD(8, segments);

#if 0
      DSP4_WRITE_WORD(0, -1);
      DSP4_WRITE_WORD(2, -1);
      DSP4_WRITE_WORD(4, -1);
      DSP4_WRITE_WORD(6, -1);
      DSP4_WRITE_WORD(8, -1);
#endif

      index = 10;

      // iterate through each point
      for (lcv = 0; lcv < segments; lcv++)
      {
         // step through the projected line
         y_out = project_y + ((py_dy * lcv) >> 8);
         x_out = project_x + ((px_dx * lcv) >> 8);

#if 0
         project_ptr = -1;
         y_out = -1;
         x_out = -1;
#endif

         // data
         DSP4_WRITE_WORD(index + 0, project_ptr);
         DSP4_WRITE_WORD(index + 2, y_out);
         DSP4_WRITE_WORD(index + 4, x_out);
         index += 6;

         // post-update
         project_ptr -= 4;
      }

      // post-update
      project_y += ((py_dy * lcv) >> 8);
      project_x += ((px_dx * lcv) >> 8);

      // new positions
      if (segments > 0)
      {
         project_x1 = project_x2;
         project_y1 = project_y2;

         // multi-op storage
         multi_focaly[multi_index2++] = project_focaly;
         multi_farplane[1] = plane;
         multi_raster[1] = project_y1 - 1;
      }

      // update projection points
      project_pitchy += (int8_t)DSP4.parameters[3];
      project_pitchx += (int8_t)DSP4.parameters[5];

      project_focaly += project_pitchy;
      project_focalx += project_pitchx;
   }
   while (1);

   // terminate op
   DSP4.waiting4command = true;
   DSP4.out_count = 0;
}

#undef PRINT

#if OP==0x0007
#define PRINT
#endif

void DSP4_Op07()
{
   uint16_t command;

   DSP4.waiting4command = false;

   // op flow control
   switch (DSP4_Logic)
   {
   case 1:
      goto resume1;
      break;
   case 2:
      goto resume2;
      break;
   }

   ////////////////////////////////////////////////////
   // sort inputs

   // 0x00 = DSP4_READ_WORD(0x00);
   project_focaly = DSP4_READ_WORD(0x02);
   raster = DSP4_READ_WORD(0x04);
   viewport_top = DSP4_READ_WORD(0x06);
   project_y = DSP4_READ_WORD(0x08);
   viewport_bottom = DSP4_READ_WORD(0x0a);
   project_x1low = DSP4_READ_WORD(0x0c);
   project_x1 = DSP4_READ_WORD(0x0e);
   project_centerx = DSP4_READ_WORD(0x10);
   project_ptr = DSP4_READ_WORD(0x12);
   // (envelope?) 0xc0 = DSP4_READ_WORD(0x14);

   // pre-compute
   view_plane = PLANE_START;

   // find projection targets
   project_y1 = project_focaly;
   project_y -= viewport_bottom;
   project_x = project_centerx + project_x1;

   // multi-op storage
   multi_index2 = 0;

   // debug
   block = 0;

#ifdef PRINT
   printf("(line %d) Op07 data %04X\n", c, (uint16_t)project_y1);
#endif

   ////////////////////////////////////////////////////
   // command check

   do
   {
      // scan next command
      DSP4.in_count = 2;

DSP4_WAIT(1) resume1:

      // inspect input
      command = DSP4_READ_WORD(0);

      // check for opcode termination
      if (command == 0x8000) break;

      // already have 2 bytes in queue
      DSP4.in_index = 2;
      DSP4.in_count = 12;

      DSP4_WAIT(2)

      ////////////////////////////////////////////////////
      // process one loop of projection

      int16_t plane;
      int16_t index, lcv;
      int16_t y_out, x_out;
      int16_t py_dy, px_dx;

resume2:
      py_dy = 0;
      px_dx = 0;

      // debug
      ++block;

      // inspect inputs
      plane = DSP4_READ_WORD(0);
      project_y2 = DSP4_READ_WORD(2);
      // ? = DSP4_READ_WORD(4);
      project_x2 = DSP4_READ_WORD(6);

      // ignore invalid data
      if ((uint16_t) plane == 0x8001) continue;

      // multi-op storage
      project_focaly = multi_focaly[multi_index2];

      // quadratic regression (rough)
      if (project_focaly >= -0x0f)
         py_dy = (int16_t)(project_focaly * project_focaly * -0.20533553
                         - 1.08330005 * project_focaly - 69.61094639);
      else
         py_dy = (int16_t)(project_focaly * project_focaly * -0.000657035759
                         - 1.07629051 * project_focaly - 65.69315963);

      // approximate # of raster lines
      segments = abs(project_y2 - project_y1);

      // prevent overdraw
      if (project_y2 >= raster) segments = 0;
      else raster = project_y2;

      // don't draw outside the window
      if (project_y2 < viewport_top) segments = 0;

      // project new positions
      if (segments > 0)
      {
         // interpolate between projected points
         px_dx = ((project_x2 - project_x1) << 8) / segments;
      }

#ifdef PRINT
      printf("(line %d) Op07 block %d, loc %04X, out %02X, project_x2 %04X\n", c,
             block, plane, segments, (uint16_t)project_x2);
#endif

      // prepare pre-output
      DSP4.out_count = 4 + 2 + 6 * segments;

      DSP4_WRITE_WORD(0, project_x2);
      DSP4_WRITE_WORD(2, project_y2);
      DSP4_WRITE_WORD(4, segments);

#if 0
      DSP4_WRITE_WORD(0, -1);
      DSP4_WRITE_WORD(2, -1);
      DSP4_WRITE_WORD(4, -1);
#endif

      index = 6;
      for (lcv = 0; lcv < segments; lcv++)
      {
         // pre-compute
         y_out = project_y + ((py_dy * lcv) >> 8);
         x_out = project_x + ((px_dx * lcv) >> 8);

#if 0
         project_ptr = -1;
         //y_out = -1;
         x_out = -1;
#endif

         // data
         DSP4_WRITE_WORD(index + 0, project_ptr);
         DSP4_WRITE_WORD(index + 2, y_out);
         DSP4_WRITE_WORD(index + 4, x_out);
         index += 6;

         // post-update
         project_ptr -= 4;
      }

      // update internal variables
      project_y += ((py_dy * lcv) >> 8);
      project_x += ((px_dx * lcv) >> 8);

      // new positions
      if (segments > 0)
      {
         project_x1 = project_x2;
         project_y1 = project_y2;

         // multi-op storage
         multi_index2++;
      }
   }
   while (1);

   DSP4.waiting4command = true;
   DSP4.out_count = 0;
}

#undef PRINT

#if OP==0x0008
#define PRINT
#endif

void DSP4_Op08()
{
   uint16_t command;

   DSP4.waiting4command = false;

   // op flow control
   switch (DSP4_Logic)
   {
   case 1:
      goto resume1;
      break;
   case 2:
      goto resume2;
      break;
   }

   ////////////////////////////////////////////////////
   // process initial inputs

   // clip values
   path_clipRight[0] = DSP4_READ_WORD(0x00);
   path_clipRight[1] = DSP4_READ_WORD(0x02);
   path_clipRight[2] = DSP4_READ_WORD(0x04);
   path_clipRight[3] = DSP4_READ_WORD(0x06);

   path_clipLeft[0] = DSP4_READ_WORD(0x08);
   path_clipLeft[1] = DSP4_READ_WORD(0x0a);
   path_clipLeft[2] = DSP4_READ_WORD(0x0c);
   path_clipLeft[3] = DSP4_READ_WORD(0x0e);

   // unknown (constant)
   // unknown (constant)

   // path positions
   path_pos[0] = DSP4_READ_WORD(0x20);
   path_pos[1] = DSP4_READ_WORD(0x22);
   path_pos[2] = DSP4_READ_WORD(0x24);
   path_pos[3] = DSP4_READ_WORD(0x26);

   // data locations
   path_ptr[0] = DSP4_READ_WORD(0x28);
   path_ptr[1] = DSP4_READ_WORD(0x2a);
   path_ptr[2] = DSP4_READ_WORD(0x2c);
   path_ptr[3] = DSP4_READ_WORD(0x2e);

   // project_y1 lines
   path_raster[0] = DSP4_READ_WORD(0x30);
   path_raster[1] = DSP4_READ_WORD(0x32);
   path_raster[2] = DSP4_READ_WORD(0x34);
   path_raster[3] = DSP4_READ_WORD(0x36);

   // viewport_top
   path_top[0] = DSP4_READ_WORD(0x38);
   path_top[1] = DSP4_READ_WORD(0x3a);
   path_top[2] = DSP4_READ_WORD(0x3c);
   path_top[3] = DSP4_READ_WORD(0x3e);

   // unknown (constants)

   view_plane = PLANE_START;

   // debug
   block = 0;

   ////////////////////////////////////////////////////
   // command check

   do
   {
      // scan next command
      DSP4.in_count = 2;

DSP4_WAIT(1) resume1:

      // inspect input
      command = DSP4_READ_WORD(0);

      // terminate op
      if (command == 0x8000) break;

      // already have 2 bytes in queue
      DSP4.in_index = 2;
      DSP4.in_count = 18;

DSP4_WAIT(2) resume2:

      ////////////////////////////////////////////////////
      // projection begins

      // debug
      ++block;

      // used in envelope shaping
      int16_t x1_final;
      int16_t x2_final;

      // look at guidelines
      int16_t plane = DSP4_READ_WORD(0x00);
      int16_t x_left = DSP4_READ_WORD(0x02);
      int16_t y_left = DSP4_READ_WORD(0x04);
      int16_t x_right = DSP4_READ_WORD(0x06);
      int16_t y_right = DSP4_READ_WORD(0x08);

      // envelope guidelines (one frame only)
      int16_t envelope1 = DSP4_READ_WORD(0x0a);
      int16_t envelope2 = DSP4_READ_WORD(0x0c);

      // ignore invalid data
      if ((uint16_t) plane == 0x8001) continue;

      // first init
      if (plane == 0x7fff)
      {
         int pos1, pos2;

         // initialize projection
         path_x[0] = x_left;
         path_x[1] = x_right;

         path_y[0] = y_left;
         path_y[1] = y_right;

         // update coordinates
         path_pos[0] -= x_left;
         path_pos[1] -= x_left;
         path_pos[2] -= x_right;
         path_pos[3] -= x_right;

         pos1 = path_pos[0] + envelope1;
         pos2 = path_pos[1] + envelope2;

         // clip offscreen data
         if (pos1 < path_clipLeft[0]) pos1 = path_clipLeft[0];
         if (pos1 > path_clipRight[0]) pos1 = path_clipRight[0];
         if (pos2 < path_clipLeft[1]) pos2 = path_clipLeft[1];
         if (pos2 > path_clipRight[1]) pos2 = path_clipRight[1];

#if 0
         pos1 = -1;
         //pos2=-1;
#endif

         path_plane[0] = plane;
         path_plane[1] = plane;

         // initial output
         DSP4.out_count = 2;
         DSP4.output[0] = pos1 & 0xFF;
         DSP4.output[1] = pos2 & 0xFF;

#ifdef PRINT
         printf("(line %d) Op08 x_left %04X\n", c, (uint16_t)x_left);
#endif
      }
      // proceed with projection
      else
      {
         int16_t index = 0, lcv;
         int16_t left_inc = 0, right_inc = 0;
         int16_t dx1 = 0, dx2 = 0, dx3, dx4;

         // # segments to traverse
         segments = abs(y_left - path_y[0]);

         // prevent overdraw
         if (y_left >= path_raster[0]) segments = 0;
         else path_raster[0] = y_left;

         // don't draw outside the window
         if (path_raster[0] < path_top[0]) segments = 0;

         // proceed if visibility rules apply
         if (segments > 0)
         {
            // use previous data
            dx1 = (envelope1 * path_plane[0] / view_plane);
            dx2 = (envelope2 * path_plane[0] / view_plane);

            // use temporary envelope pitch (this frame only)
            dx3 = (envelope1 * plane / view_plane);
            dx4 = (envelope2 * plane / view_plane);

            // project new shapes (left side)
            x1_final = x_left + dx1;
            x2_final = path_x[0] + dx3;

            // interpolate between projected points with shaping
            left_inc = ((x2_final - x1_final) << 8) / segments;

            // project new shapes (right side)
            x1_final = x_left + dx2;
            x2_final = path_x[0] + dx4;

            // interpolate between projected points with shaping
            right_inc = ((x2_final - x1_final) << 8) / segments;

            path_plane[0] = plane;
         }

#ifdef PRINT
         printf("(line %d) Op08 block %d, out %02X, raster %02X\n", c, block, segments,
                (uint16_t)y_left);
#endif

         // zone 1
         DSP4.out_count = (2 + 4 * segments);
         DSP4_WRITE_WORD(index, segments);
         index += 2;

         for (lcv = 1; lcv <= segments; lcv++)
         {
            int16_t pos1, pos2;

            // pre-compute
            pos1 = path_pos[0] + ((left_inc * lcv) >> 8) + dx1;
            pos2 = path_pos[1] + ((right_inc * lcv) >> 8) + dx2;

            // clip offscreen data
            if (pos1 < path_clipLeft[0]) pos1 = path_clipLeft[0];
            if (pos1 > path_clipRight[0]) pos1 = path_clipRight[0];
            if (pos2 < path_clipLeft[1]) pos2 = path_clipLeft[1];
            if (pos2 > path_clipRight[1]) pos2 = path_clipRight[1];

#if 0
            if (pos1 == 0x00ff) pos1 = 0;
            if (pos2 == 0x00ff) pos2 = 0;
            path_ptr[0] = -1;
            pos1 = -1;
            pos2 = -1;
#endif

            // data
            DSP4_WRITE_WORD(index, path_ptr[0]);
            index += 2;
            DSP4.output[index++] = pos1 & 0xFF;
            DSP4.output[index++] = pos2 & 0xFF;

            // post-update
            path_ptr[0] -= 4;
            path_ptr[1] -= 4;
         }
         lcv--;

         if (segments > 0)
         {
            // project points w/out the envelopes
            int16_t inc = ((path_x[0] - x_left) << 8) / segments;

            // post-store
            path_pos[0] += ((inc * lcv) >> 8);
            path_pos[1] += ((inc * lcv) >> 8);

            path_x[0] = x_left;
            path_y[0] = y_left;
         }

         //////////////////////////////////////////////
         // zone 2
         segments = abs(y_right - path_y[1]);

         // prevent overdraw
         if (y_right >= path_raster[2]) segments = 0;
         else path_raster[2] = y_right;

         // don't draw outside the window
         if (path_raster[2] < path_top[2]) segments = 0;

         // proceed if visibility rules apply
         if (segments > 0)
         {
            // use previous data
            dx1 = (envelope1 * path_plane[1] / view_plane);
            dx2 = (envelope2 * path_plane[1] / view_plane);

            // use temporary envelope pitch (this frame only)
            dx3 = (envelope1 * plane / view_plane);
            dx4 = (envelope2 * plane / view_plane);

            // project new shapes (left side)
            x1_final = x_left + dx1;
            x2_final = path_x[1] + dx3;

            // interpolate between projected points with shaping
            left_inc = ((x2_final - x1_final) << 8) / segments;

            // project new shapes (right side)
            x1_final = x_left + dx2;
            x2_final = path_x[1] + dx4;

            // interpolate between projected points with shaping
            right_inc = ((x2_final - x1_final) << 8) / segments;

            path_plane[1] = plane;
         }

         // write out results
         DSP4.out_count += (2 + 4 * segments);
         DSP4_WRITE_WORD(index, segments);
         index += 2;

         for (lcv = 1; lcv <= segments; lcv++)
         {
            int16_t pos1, pos2;

            // pre-compute
            pos1 = path_pos[2] + ((left_inc * lcv) >> 8) + dx1;
            pos2 = path_pos[3] + ((right_inc * lcv) >> 8) + dx2;

            // clip offscreen data
            if (pos1 < path_clipLeft[2]) pos1 = path_clipLeft[2];
            if (pos1 > path_clipRight[2]) pos1 = path_clipRight[2];
            if (pos2 < path_clipLeft[3]) pos2 = path_clipLeft[3];
            if (pos2 > path_clipRight[3]) pos2 = path_clipRight[3];

#if 0
            if (pos1 == 0x00ff) pos1 = 0;
            if (pos2 == 0x00ff) pos2 = 0;
            path_ptr[2] = -1;
            //pos1 = -1;
            pos2 = -1;
#endif

            // data
            DSP4_WRITE_WORD(index, path_ptr[2]);
            index += 2;
            DSP4.output[index++] = pos1 & 0xFF;
            DSP4.output[index++] = pos2 & 0xFF;

            // post-update
            path_ptr[2] -= 4;
            path_ptr[3] -= 4;
         }
         lcv--;

         if (segments > 0)
         {
            // project points w/out the envelopes
            int16_t inc = ((path_x[1] - x_right) << 8) / segments;

            // post-store
            path_pos[2] += ((inc * lcv) >> 8);
            path_pos[3] += ((inc * lcv) >> 8);

            path_x[1] = x_right;
            path_y[1] = y_right;
         }
      }
   }
   while (1);

   DSP4.waiting4command = true;
   DSP4.out_count = 2;
   DSP4_WRITE_WORD(0, 0);
}

#undef PRINT

#if OP==0x000D
#define PRINT
#endif

void DSP4_Op0D()
{
   uint16_t command;

   DSP4.waiting4command = false;

   // op flow control
   switch (DSP4_Logic)
   {
   case 1:
      goto resume1;
      break;
   case 2:
      goto resume2;
      break;
   }

   ////////////////////////////////////////////////////
   // process initial inputs

   // sort inputs
   // 0x00 = DSP4_READ_WORD(0x00);
   project_focaly = DSP4_READ_WORD(0x02);
   raster = DSP4_READ_WORD(0x04);
   viewport_top = DSP4_READ_WORD(0x06);
   project_y = DSP4_READ_WORD(0x08);
   viewport_bottom = DSP4_READ_WORD(0x0a);
   project_x1low = DSP4_READ_WORD(0x0c);
   project_x1 = DSP4_READ_WORD(0x0e);
   project_focalx = DSP4_READ_WORD(0x0e);
   project_centerx = DSP4_READ_WORD(0x10);
   project_ptr = DSP4_READ_WORD(0x12);
   // 0xc0 = DSP4_READ_WORD(0x14);
   project_pitchylow = DSP4_READ_WORD(0x16);
   project_pitchy = DSP4_READ_WORD(0x18);
   project_pitchxlow = DSP4_READ_WORD(0x1a);
   project_pitchx = DSP4_READ_WORD(0x1c);
   far_plane = DSP4_READ_WORD(0x1e);
   // ? = DSP4_READ_WORD(0x20);

   // multi-op storage
   multi_index1++;
   multi_index1 %= 4;

   // remap 0D->09 window data ahead of time
   // index starts at 1-3,0
   //
   // Op0D: BL,TL,BR,TR
   // Op09: TL,TR,BL,BR (1,2,3,0)
   switch (multi_index1)
   {
   case 1:
      multi_index2 = 3;
      break;
   case 2:
      multi_index2 = 1;
      break;
   case 3:
      multi_index2 = 0;
      break;
   case 0:
      multi_index2 = 2;
      break;
   }

   // pre-compute
   view_plane = PLANE_START;

   // figure out projection data
   project_y -= viewport_bottom;
   project_x = project_centerx + project_x1;

   // debug
   block = 0;

   ////////////////////////////////////////////////////
   // command check

   do
   {
      // scan next command
      DSP4.in_count = 2;

DSP4_WAIT(1) resume1:

      // inspect input
      command = DSP4_READ_WORD(0);

      // terminate op
      if (command == 0x8000) break;

      // already have 2 bytes in queue
      DSP4.in_index = 2;
      DSP4.in_count = 8;

      DSP4_WAIT(2)

      ////////////////////////////////////////////////////
      // project section of the track

      // inspect inputs
      int16_t plane;
      int16_t index, lcv;
      int16_t py_dy, px_dx;
      int16_t y_out, x_out;

resume2:

      plane = DSP4_READ_WORD(0);
      py_dy = 0;
      px_dx = 0;


      // ignore invalid data
      if ((uint16_t) plane == 0x8001) continue;

      // one-time init
      if (far_plane)
      {
         // setup final data
         // low16=plane
         project_x1 = project_focalx;
         project_y1 = project_focaly;
         plane = far_plane;
         far_plane = 0;
      }

      // use proportional triangles to project new coords
      project_x2 = project_focalx * plane / view_plane;
      project_y2 = project_focaly * plane / view_plane;

      // quadratic regression (rough)
      if (project_focaly >= -0x0f)
         py_dy = (int16_t)(project_focaly * project_focaly * -0.20533553
                         - 1.08330005 * project_focaly - 69.61094639);
      else
         py_dy = (int16_t)(project_focaly * project_focaly * -0.000657035759
                         - 1.07629051 * project_focaly - 65.69315963);

      // approximate # of raster lines
      segments = abs(project_y2 - project_y1);

      // prevent overdraw
      if (project_y2 >= raster) segments = 0;
      else raster = project_y2;

      // don't draw outside the window
      if (project_y2 < viewport_top) segments = 0;

      // project new positions
      if (segments > 0)
      {
         // interpolate between projected points
         px_dx = ((project_x2 - project_x1) << 8) / segments;
      }

      // debug
      ++block;

#ifdef PRINT
      printf("(line %d) Op0D check %02X, plane %04X\n", c, (uint16_t)segments,
             (uint16_t)(plane));
#endif

      // prepare output
      DSP4.out_count = 8 + 2 + 6 * segments;

      DSP4_WRITE_WORD(0, project_focalx);
      DSP4_WRITE_WORD(2, project_x2);
      DSP4_WRITE_WORD(4, project_focaly);
      DSP4_WRITE_WORD(6, project_y2);
      DSP4_WRITE_WORD(8, segments);
#if 0
      DSP4_WRITE_WORD(0, -1);
      DSP4_WRITE_WORD(2, -1);
      DSP4_WRITE_WORD(4, -1);
      DSP4_WRITE_WORD(6, -1);
      DSP4_WRITE_WORD(8, -1);
#endif

      index = 10;

      // iterate through each point
      for (lcv = 0; lcv < segments; lcv++)
      {
         // step through the projected line
         y_out = project_y + ((py_dy * lcv) >> 8);
         x_out = project_x + ((px_dx * lcv) >> 8);

#if 0
         project_ptr = -1;
         //y_out=-1;
         x_out = -1;
#endif

         // data
         DSP4_WRITE_WORD(index + 0, project_ptr);
         DSP4_WRITE_WORD(index + 2, y_out);
         DSP4_WRITE_WORD(index + 4, x_out);
         index += 6;

         // post-update
         project_ptr -= 4;
      }

      // post-update
      project_y += ((py_dy * lcv) >> 8);
      project_x += ((px_dx * lcv) >> 8);

      if (segments > 0)
      {
         project_x1 = project_x2;
         project_y1 = project_y2;

         // multi-op storage
         multi_farplane[multi_index2] = plane;
         multi_raster[multi_index2] = project_y1;
      }

      // update focal projection points
      project_pitchy += (int8_t)DSP4.parameters[3];
      project_pitchx += (int8_t)DSP4.parameters[5];

      project_focaly += project_pitchy;
      project_focalx += project_pitchx;
   }
   while (1);

   DSP4.waiting4command = true;
   DSP4.out_count = 0;
}

#undef PRINT

#if OP==0x0009
#define PRINT
#endif

#if OP==0x0006
#define PRINT
#endif

void DSP4_Op09()
{
   uint16_t command;

   DSP4.waiting4command = false;

   // op flow control
   switch (DSP4_Logic)
   {
   case 1:
      goto resume1;
      break;
   case 2:
      goto resume2;
      break;
   case 3:
      goto resume3;
      break;
   case 4:
      goto resume4;
      break;
   case 5:
      goto resume5;
      break;
   case 6:
      goto resume6;
      break;
   case 7:
      goto resume7;
      break;
   }

   ////////////////////////////////////////////////////
   // process initial inputs

   // debug
   block = 0;

   // grab screen information
   view_plane = PLANE_START;
   center_x = DSP4_READ_WORD(0x00);
   center_y = DSP4_READ_WORD(0x02);
   // 0x00 = DSP4_READ_WORD(0x04);
   viewport_left = DSP4_READ_WORD(0x06);
   viewport_right = DSP4_READ_WORD(0x08);
   viewport_top = DSP4_READ_WORD(0x0a);
   viewport_bottom = DSP4_READ_WORD(0x0c);

#ifdef PRINT2
   printf("Window: (%04X,%04X) (%04X,%04X)\n",
          viewport_left, viewport_right, viewport_top, viewport_bottom);
#endif

   // expand viewport dimensions
   viewport_left -= 8;

   // cycle through viewport window data
   multi_index1++;
   multi_index1 %= 4;

#if 1
   // convert track line to the window region
   project_y2 = center_y + multi_raster[multi_index1] *
                (viewport_bottom - center_y) / (0x33 - 0);
   if (op09_mode == 0) project_y2 -= 2;
#endif

   goto no_sprite;

   do
   {
      ////////////////////////////////////////////////////
      // check for new sprites

      do
      {
         uint16_t second;

         DSP4.in_count = 4;
         DSP4.in_index = 2;

DSP4_WAIT(1) resume1:

         // try to classify sprite
         second = DSP4_READ_WORD(2);

         // op termination
         if (second == 0x8000) goto terminate;

         second >>= 8;
         sprite_type = 0;

         // vehicle sprite
         if (second == 0x90)
         {
            sprite_type = 1;
            break;
         }
         // terrain sprite
         else if (second != 0)
         {
            sprite_type = 2;
            break;
         }

no_sprite:
         // no sprite. try again

         DSP4.in_count = 2;

DSP4_WAIT(2) resume2:
         ;
      }
      while (1);

      ////////////////////////////////////////////////////
      // process projection information

sprite_found:
      // vehicle sprite
      if (sprite_type == 1)
      {
         int16_t plane;
         int16_t car_left, car_right;
         // int16_t car_left_a;
         int16_t focal_back;
//         int16_t focal_front;

         // we already have 4 bytes we want
         DSP4.in_count = 6 + 12;
         DSP4.in_index = 4;

DSP4_WAIT(3) resume3:

         // filter inputs
         project_y1 = DSP4_READ_WORD(0x00);
         focal_back = DSP4_READ_WORD(0x06);
         // focal_front = DSP4_READ_WORD(0x08);
         // car_left_a = DSP4_READ_WORD(0x0a);
         car_left = DSP4_READ_WORD(0x0c);
         plane = DSP4_READ_WORD(0x0e);
         car_right = DSP4_READ_WORD(0x10);

         // calculate car's x-center
         project_focalx = car_right - car_left;

         // determine how far into the screen to project
         project_focaly = focal_back;
         project_x = project_focalx * plane / view_plane;
         segments = 0x33 - project_focaly * plane / view_plane;
         far_plane = plane;

         // prepare memory
         sprite_x = center_x + project_x;
         sprite_y = viewport_bottom - segments;
         far_plane = plane;

         // debug
         ++block;

         // make the car's x-center available
         DSP4.out_count = 2;
         DSP4_WRITE_WORD(0, project_focalx);

         // grab a few remaining vehicle values
         DSP4.in_count = 4;

         DSP4_WAIT(4)

         // store final values
         int height;

resume4:
         height = DSP4_READ_WORD(0);
         sprite_offset = DSP4_READ_WORD(2);

         // vertical lift factor
         sprite_y += height;
      }
      // terrain sprite
      else if (sprite_type == 2)
      {
         int16_t plane;

         // we already have 4 bytes we want
         DSP4.in_count = 6 + 6 + 2;
         DSP4.in_index = 4;

DSP4_WAIT(5) resume5:

         // sort loop inputs
         project_y1 = DSP4_READ_WORD(0x00);
         plane = DSP4_READ_WORD(0x02);
         project_centerx = DSP4_READ_WORD(0x04);
         //project_y1 = DSP4_READ_WORD(0x06);
         project_focalx = DSP4_READ_WORD(0x08);
         project_focaly = DSP4_READ_WORD(0x0a);
         sprite_offset = DSP4_READ_WORD(0x0c);

         // determine distances into virtual world
         segments = 0x33 - project_y1;
         project_x = project_focalx * plane / view_plane;
         project_y = project_focaly * plane / view_plane;

         // prepare memory
         sprite_x = center_x + project_x - project_centerx;
         sprite_y = viewport_bottom - segments + project_y;
         far_plane = plane;

         // debug
         ++block;
      }

      // default sprite size: 16x16
      sprite_size = 1;

      // convert tile data to OAM

      do
      {
         DSP4.in_count = 2;

DSP4_WAIT(6) resume6:

         command = DSP4_READ_WORD(0);

         // opcode termination
         if (command == 0x8000) goto terminate;

         // toggle sprite size
         if (command == 0x0000)
         {
            sprite_size = !sprite_size;
#ifdef PRINT
            printf("TOGGLE=%02X\n", (uint8_t)sprite_size);
#endif
            continue;
         }

         // new sprite information
         command >>= 8;
         if (command != 0x20 && command != 0x40 &&
               command != 0x60 && command != 0xa0 &&
               command != 0xc0 && command != 0xe0)
            break;

         DSP4.in_count = 6;
         DSP4.in_index = 2;

         DSP4_WAIT(7)

         /////////////////////////////////////
         // process tile data

         bool clip;
         int16_t sp_x, sp_y, sp_oam, sp_msb;
         int16_t sp_dx, sp_dy;

resume7:

         // sprite deltas
         sp_dy = DSP4_READ_WORD(2);
         sp_dx = DSP4_READ_WORD(4);

         // update coordinates
         sp_y = sprite_y + sp_dy;
         sp_x = sprite_x + sp_dx;

         // reject points outside the clipping window
         clip = false;
         if (sp_x < viewport_left || sp_x > viewport_right) clip = true;
         if (sp_y < viewport_top || sp_y > viewport_bottom) clip = true;

         // track depth sorting
         if (far_plane <= multi_farplane[multi_index1] &&
               sp_y >= project_y2) clip = true;

#ifdef PRINT2
         printf("(line %d) %04X, %04X, %04X / %04X %04X\n", line,
                (uint16_t)sp_x, (uint16_t)sp_y, (uint16_t)far_plane,
                (uint16_t)multi_farplane[multi_index1], (uint16_t)project_y2);
#endif

         // don't draw offscreen coordinates
         DSP4.out_count = 0;
         if (!clip)
         {
            int16_t out_index = 0;
            int16_t offset = DSP4_READ_WORD(0);

            // update sprite nametable/attribute information
            sp_oam = sprite_offset + offset;
            sp_msb = (sp_x < 0 || sp_x > 255);

#ifdef PRINT
            printf("(line %d) %04X, %04X, %04X, %04X, %04X\n", line,
                   (uint16_t)sp_oam, (uint16_t)sprite_offset, (uint16_t)offset,
                   (uint16_t)sp_x, (uint16_t)sp_y);
#endif

            // emit transparency information
            if (
               (sprite_offset & 0x08) &&
               ((sprite_type == 1 && sp_y >= 0xcc) ||
                (sprite_type == 2 && sp_y >= 0xbb))
            )
            {
               DSP4.out_count = 6;

               // one block of OAM data
               DSP4_WRITE_WORD(0, 1);

               // OAM: x,y,tile,no attr
               DSP4.output[2] = sp_x & 0xFF;
               DSP4.output[3] = (sp_y + 6) & 0xFF;
               DSP4_WRITE_WORD(4, 0xEE);

               out_index = 6;

               // OAM: size,msb data
               DSP4_Op06(sprite_size, (char) sp_msb);
            }

            // normal data
            DSP4.out_count += 8;

            // one block of OAM data
            DSP4_WRITE_WORD(out_index + 0, 1);

            // OAM: x,y,tile,attr
            DSP4.output[out_index + 2] = sp_x & 0xFF;
            DSP4.output[out_index + 3] = sp_y & 0xFF;
            DSP4_WRITE_WORD(out_index + 4, sp_oam);

            // no following OAM data
            DSP4_WRITE_WORD(out_index + 6, 0);

            // OAM: size,msb data
            DSP4_Op06(sprite_size, (char) sp_msb);

#if 0
            DSP4_WRITE_WORD(0, -1);
            DSP4_WRITE_WORD(2, -1);
            DSP4_WRITE_WORD(4, -1);
            DSP4_WRITE_WORD(6, -1);
            DSP4_WRITE_WORD(8, -1);
            DSP4_WRITE_WORD(10, -1);
            DSP4_WRITE_WORD(12, -1);
#endif
         }

         // no sprite information
         if (DSP4.out_count == 0)
         {
            DSP4.out_count = 2;
            DSP4_WRITE_WORD(0, 0);
         }
      }
      while (1);

      /////////////////////////////////////
      // special cases: plane == 0x0000

      // special vehicle case
      if (command == 0x90)
      {
         sprite_type = 1;

         // shift bytes
         DSP4.parameters[2] = DSP4.parameters[0];
         DSP4.parameters[3] = DSP4.parameters[1];
         DSP4.parameters[0] = 0;
         DSP4.parameters[1] = 0;

         goto sprite_found;
      }
      // special terrain case
      else if (command != 0x00 && command != 0xff)
      {
         sprite_type = 2;

         // shift bytes
         DSP4.parameters[2] = DSP4.parameters[0];
         DSP4.parameters[3] = DSP4.parameters[1];
         DSP4.parameters[0] = 0;
         DSP4.parameters[1] = 0;

         goto sprite_found;
      }
   }
   while (1);

terminate:
   DSP4.waiting4command = true;
   DSP4.out_count = 0;
}

#undef PRINT