dsp4emu.c

来自「linux下的任天堂模拟器代码。供大家参考。」· C语言 代码 · 共 2,173 行 · 第 1/5 页

          x_left = (int16)(win_left >> 16);
          x_right = (int16)(win_right >> 16);

          // saturate offscreen data
          if (x_left < DSP4_vars.poly_clipLf[polygon][0])
            x_left = DSP4_vars.poly_clipLf[polygon][0];
          if (x_left > DSP4_vars.poly_clipRt[polygon][0])
            x_left = DSP4_vars.poly_clipRt[polygon][0];
          if (x_right < DSP4_vars.poly_clipLf[polygon][1])
            x_right = DSP4_vars.poly_clipLf[polygon][1];
          if (x_right > DSP4_vars.poly_clipRt[polygon][1])
            x_right = DSP4_vars.poly_clipRt[polygon][1];

          // 1. HDMA memory pointer
          // 2. Left window position ($2126/$2128)
          // 3. Right window position ($2127/$2129)

          DSP4_WRITE_WORD(DSP4_vars.poly_ptr[polygon][0]);
          DSP4_WRITE_BYTE(x_left & 0xff);
          DSP4_WRITE_BYTE(x_right & 0xff);


          // update memory pointers
          DSP4_vars.poly_ptr[polygon][0] -= 4;
          DSP4_vars.poly_ptr[polygon][1] -= 4;
        } // end rasterize line
      }

      ////////////////////////////////////////////////
      // Post-update

      // new projection spot to continue rasterizing from
      DSP4_vars.poly_start[polygon] = view_x[poly];
    } // end polygon rasterizer
  }
  while (1);

  // unknown output
  DSP4_CLEAR_OUT();
  DSP4_WRITE_WORD(0);


  DSP4.waiting4command = TRUE;
}

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

void DSP4_OP09()
{
  DSP4.waiting4command = FALSE;

  // op flow control
  switch (DSP4_vars.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;
  }

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

  // grab screen information
  DSP4_vars.viewport_cx = DSP4_READ_WORD();
  DSP4_vars.viewport_cy = DSP4_READ_WORD();
  DSP4_READ_WORD(); // 0x0000
  DSP4_vars.viewport_left = DSP4_READ_WORD();
  DSP4_vars.viewport_right = DSP4_READ_WORD();
  DSP4_vars.viewport_top = DSP4_READ_WORD();
  DSP4_vars.viewport_bottom = DSP4_READ_WORD();

  // starting DSP4_vars.raster line below the horizon
  DSP4_vars.poly_bottom[0][0] = DSP4_vars.viewport_bottom - DSP4_vars.viewport_cy;
  DSP4_vars.poly_raster[0][0] = 0x100;

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

    DSP4.in_count = 4;
    DSP4_WAIT(1) resume1 :

    ////////////////////////////////////////////////
    // DSP4_vars.raster overdraw check

    DSP4_vars.raster = DSP4_READ_WORD();

    // continue updating the DSP4_vars.raster line where overdraw begins
    if (DSP4_vars.raster < DSP4_vars.poly_raster[0][0])
    {
      DSP4_vars.sprite_clipy = DSP4_vars.viewport_bottom - (DSP4_vars.poly_bottom[0][0] - DSP4_vars.raster);
      DSP4_vars.poly_raster[0][0] = DSP4_vars.raster;
    }

    /////////////////////////////////////////////////
    // identify sprite

    // op termination
    DSP4_vars.distance = DSP4_READ_WORD();
    if (DSP4_vars.distance == -0x8000)
      goto terminate;


    // no sprite
    if (DSP4_vars.distance == 0x0000)
    {
      continue;
    }

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

    // vehicle sprite
    if ((uint16) DSP4_vars.distance == 0x9000)
    {
      int16 car_left, car_right, car_back;
      int16 impact_left, impact_back;
      int16 world_spx, world_spy;
      int16 view_spx, view_spy;
      uint16 energy;

      // we already have 4 bytes we want
      DSP4.in_count = 14;
      DSP4_WAIT(2) resume2 :

      // filter inputs
      energy = DSP4_READ_WORD();
      impact_back = DSP4_READ_WORD();
      car_back = DSP4_READ_WORD();
      impact_left = DSP4_READ_WORD();
      car_left = DSP4_READ_WORD();
      DSP4_vars.distance = DSP4_READ_WORD();
      car_right = DSP4_READ_WORD();

      // calculate car's world (x,y) values
      world_spx = car_right - car_left;
      world_spy = car_back;

      // add in collision vector [needs bit-twiddling]
      world_spx -= energy * (impact_left - car_left) >> 16;
      world_spy -= energy * (car_back - impact_back) >> 16;

      // perspective correction for world (x,y)
      view_spx = world_spx * DSP4_vars.distance >> 15;
      view_spy = world_spy * DSP4_vars.distance >> 15;

      // convert to screen values
      DSP4_vars.sprite_x = DSP4_vars.viewport_cx + view_spx;
      DSP4_vars.sprite_y = DSP4_vars.viewport_bottom - (DSP4_vars.poly_bottom[0][0] - view_spy);

      // make the car's (x)-coordinate available
      DSP4_CLEAR_OUT();
      DSP4_WRITE_WORD(world_spx);

      // grab a few remaining vehicle values
      DSP4.in_count = 4;
      DSP4_WAIT(3) resume3 :

      // add vertical lift factor
      DSP4_vars.sprite_y += DSP4_READ_WORD();
    }
    // terrain sprite
    else
    {
      int16 world_spx, world_spy;
      int16 view_spx, view_spy;

      // we already have 4 bytes we want
      DSP4.in_count = 10;
      DSP4_WAIT(4) resume4 :

      // sort loop inputs
      DSP4_vars.poly_cx[0][0] = DSP4_READ_WORD();
      DSP4_vars.poly_raster[0][1] = DSP4_READ_WORD();
      world_spx = DSP4_READ_WORD();
      world_spy = DSP4_READ_WORD();

      // compute base DSP4_vars.raster line from the bottom
      DSP4_vars.segments = DSP4_vars.poly_bottom[0][0] - DSP4_vars.raster;

      // perspective correction for world (x,y)
      view_spx = world_spx * DSP4_vars.distance >> 15;
      view_spy = world_spy * DSP4_vars.distance >> 15;

      // convert to screen values
      DSP4_vars.sprite_x = DSP4_vars.viewport_cx + view_spx - DSP4_vars.poly_cx[0][0];
      DSP4_vars.sprite_y = DSP4_vars.viewport_bottom - DSP4_vars.segments + view_spy;
    }

    // default sprite size: 16x16
    DSP4_vars.sprite_size = 1;
    DSP4_vars.sprite_attr = DSP4_READ_WORD();

    ////////////////////////////////////////////////////
    // convert tile data to SNES OAM format

    do
    {
      uint16 header;

      int16 sp_x, sp_y, sp_attr, sp_dattr;
      int16 sp_dx, sp_dy;
      int16 pixels;

      bool8 draw;

      DSP4.in_count = 2;
      DSP4_WAIT(5) resume5 :

      draw = TRUE;

      // opcode termination
      DSP4_vars.raster = DSP4_READ_WORD();
      if (DSP4_vars.raster == -0x8000)
        goto terminate;

      // stop code
      if (DSP4_vars.raster == 0x0000 && !DSP4_vars.sprite_size)
        break;

      // toggle sprite size
      if (DSP4_vars.raster == 0x0000)
      {
        DSP4_vars.sprite_size = !DSP4_vars.sprite_size;
        continue;
      }

      // check for valid sprite header
      header = DSP4_vars.raster;
      header >>= 8;
      if (header != 0x20 &&
          header != 0x2e && //This is for attractor sprite
          header != 0x40 &&
          header != 0x60 &&
          header != 0xa0 &&
          header != 0xc0 &&
          header != 0xe0)
        break;

      // read in rest of sprite data
      DSP4.in_count = 4;
      DSP4_WAIT(6) resume6 :

      draw = TRUE;

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

      // sprite deltas
      sp_dattr = DSP4_vars.raster;
      sp_dy = DSP4_READ_WORD();
      sp_dx = DSP4_READ_WORD();

      // update coordinates to screen space
      sp_x = DSP4_vars.sprite_x + sp_dx;
      sp_y = DSP4_vars.sprite_y + sp_dy;

      // update sprite nametable/attribute information
      sp_attr = DSP4_vars.sprite_attr + sp_dattr;

      // allow partially visibile tiles
      pixels = DSP4_vars.sprite_size ? 15 : 7;

      DSP4_CLEAR_OUT();

      // transparent tile to clip off parts of a sprite (overdraw)
      if (DSP4_vars.sprite_clipy - pixels <= sp_y &&
          sp_y <= DSP4_vars.sprite_clipy &&
          sp_x >= DSP4_vars.viewport_left - pixels &&
          sp_x <= DSP4_vars.viewport_right &&
          DSP4_vars.sprite_clipy >= DSP4_vars.viewport_top - pixels &&
          DSP4_vars.sprite_clipy <= DSP4_vars.viewport_bottom)
      {
        DSP4_OP0B(&draw, sp_x, DSP4_vars.sprite_clipy, 0x00EE, DSP4_vars.sprite_size, 0);
      }


      // normal sprite tile
      if (sp_x >= DSP4_vars.viewport_left - pixels &&
          sp_x <= DSP4_vars.viewport_right &&
          sp_y >= DSP4_vars.viewport_top - pixels &&
          sp_y <= DSP4_vars.viewport_bottom &&
          sp_y <= DSP4_vars.sprite_clipy)
      {
        DSP4_OP0B(&draw, sp_x, sp_y, sp_attr, DSP4_vars.sprite_size, 0);
      }


      // no following OAM data
      DSP4_OP0B(&draw, 0, 0x0100, 0, 0, 1);
    }
    while (1);
  }
  while (1);

  terminate : DSP4.waiting4command = TRUE;
}

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

const uint16 OP0A_Values[16] = { 0x0000, 0x0030, 0x0060, 0x0090, 0x00c0, 0x00f0, 0x0120, 0x0150, 0xfe80,
                                 0xfeb0, 0xfee0, 0xff10, 0xff40, 0xff70, 0xffa0, 0xffd0 };

void DSP4_OP0A(int16 n2, int16 *o1, int16 *o2, int16 *o3, int16 *o4)
{
  *o4 = OP0A_Values[(n2 & 0x000f)];
  *o3 = OP0A_Values[(n2 & 0x00f0) >> 4];
  *o2 = OP0A_Values[(n2 & 0x0f00) >> 8];
  *o1 = OP0A_Values[(n2 & 0xf000) >> 12];
}

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

void DSP4_OP0B(bool8 *draw, int16 sp_x, int16 sp_y, int16 sp_attr, bool8 size, bool8 stop)
{
  int16 Row1, Row2;

  // SR = 0x00

  // align to nearest 8-pixel row
  Row1 = (sp_y >> 3) & 0x1f;
  Row2 = (Row1 + 1) & 0x1f;

  // check boundaries
  if (!((sp_y < 0) || ((sp_y & 0x01ff) < 0x00eb)))
  {
    *draw = 0;
  }
  if (size)
  {
    if (DSP4_vars.OAM_Row[Row1] + 1 >= DSP4_vars.OAM_RowMax)
      *draw = 0;
    if (DSP4_vars.OAM_Row[Row2] + 1 >= DSP4_vars.OAM_RowMax)
      *draw = 0;
  }
  else
  {
    if (DSP4_vars.OAM_Row[Row1] >= DSP4_vars.OAM_RowMax)
    {
      *draw = 0;
    }
  }

  // emulator fail-safe (unknown if this really exists)
  if (DSP4_vars.sprite_count >= 128)
  {
    *draw = 0;
  }

  // SR = 0x80

  if (*draw)
  {
    // Row tiles
    if (size)
    {
      DSP4_vars.OAM_Row[Row1] += 2;
      DSP4_vars.OAM_Row[Row2] += 2;
    }
    else
    {
      DSP4_vars.OAM_Row[Row1]++;
    }

    // yield OAM output
    DSP4_WRITE_WORD(1);

    // pack OAM data: x,y,name,attr
    DSP4_WRITE_BYTE(sp_x & 0xff);
    DSP4_WRITE_BYTE(sp_y & 0xff);
    DSP4_WRITE_WORD(sp_attr);

    DSP4_vars.sprite_count++;

    // OAM: size,msb data
    // save post-oam table data for future retrieval
    DSP4_vars.OAM_attr[DSP4_vars.OAM_index] |= ((sp_x <0 || sp_x> 255) << DSP4_vars.OAM_bits);
    DSP4_vars.OAM_bits++;

    DSP4_vars.OAM_attr[DSP4_vars.OAM_index] |= (size << DSP4_vars.OAM_bits);
    DSP4_vars.OAM_bits++;

    // move to next byte in buffer
    if (DSP4_vars.OAM_bits == 16)
    {
      DSP4_vars.OAM_bits = 0;
      DSP4_vars.OAM_index++;
    }
  }
  else if (stop)
  {
    // yield no OAM output
    DSP4_WRITE_WORD(0);
  }
}

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

void DSP4_OP0D()
{
  DSP4.waiting4command = FALSE;

  // op flow control
  switch (DSP4_vars.DSP4_Logic)
  {
    case 1:
      goto resume1; break;
    case 2:
      goto resume2; break;
  }

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

  // sort inputs
  DSP4_vars.world_y = DSP4_READ_DWORD();
  DSP4_vars.poly_bottom[0][0] = DSP4_READ_WORD();
  DSP4_vars.poly_top[0][0] = DSP4_READ_WORD();
  DSP4_vars.poly_cx[1][0] = DSP4_READ_WORD();
  DSP4_vars.viewport_bottom = DSP4_READ_WORD();
  DSP4_vars.world_x = DSP4_READ_DWORD();
  DSP4_vars.poly_cx[0][0] = DSP4_READ_WORD();
  DSP4_vars.poly_ptr[0][0] = DSP4_READ_WORD();
  DSP4_vars.world_yofs = DSP4_READ_WORD();
  DSP4_vars.world_dy = DSP4_READ_DWORD();