mkgra.c

来自「DGen源码最后版本」· C语言 代码 · 共 270 行

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

// Builder for the gra.asm NASM module
// Renders md tiles

// Currently 15-bit and 16-bit are the same, since
// the palette value is just copied across, so use draw_tile_16() for both

static int depth_to_bytes(int depth)
{
       if (depth<=8)  return 1;
  else if (depth<=16) return 2;
  else if (depth<=24) return 3;
  else                return 4;
}


static int emit_clear_to_col(FILE *hand,int bpp)
{
  fprintf (hand,";extern \"C\" int clear_to_col_%d\n",bpp);
  fprintf (hand,
    ";  (unsigned char *dest,int len,unsigned int col);\n"
    "\n"
  );

  fprintf (hand,"global _clear_to_col_%d\n",bpp);
  fprintf (hand,"times ($$-$) & 3 db 0\n");
  fprintf (hand,"_clear_to_col_%d:\n",bpp);
  fprintf (hand,
    "push edi\n"
    "push ecx\n"
    "mov edi,[esp+12] ; edi is a pointer to the bitmap\n"
    "mov ecx,[esp+16] ; ecx is the amount of pixel to clear\n"
    "mov eax,[esp+20] ; eax is the color\n"
  );

  if (bpp<=8)
    fprintf (hand,"rep stosb\n");
  else if (bpp<=16)
    fprintf (hand,"rep stosw\n");
  else if (bpp<=24)
  {
    fprintf (hand,"clear_to_col_twenty_four:\n");
    fprintf (hand,"  stosw\n");
    fprintf (hand,"  ror eax,16\n");
    fprintf (hand,"  stosb\n");
    fprintf (hand,"  rol eax,16\n");
    fprintf (hand,"loop clear_to_col_twenty_four\n");
    ; // help!
  }
  else
    fprintf (hand,"rep stosd\n");

  fprintf (hand,
    "pop  ecx\n"
    "pop  edi\n"
    "xor eax,eax\n"
    "ret\n"
    "\n\n\n"
  );

  return 0;
}



static int emit_draw_tile(FILE *hand,int bpp,int flip,int interlace)
{
  static int label_no=0;
//  static int xloop_no=0,yloop_no=0;
  // flip&1 = horizontal flip   flip&2 = vertical flip
  static char fname[4][7]={"","_hf","_vf","_hf_vf"};
  flip&=3;

  fprintf (hand,
    ";  (unsigned char *dest,int pitch,unsigned char *tilep,unsigned int *palette);\n"
    ";//                 %%1       %%2            %%3                 %%4\n"
    "\n"
  );
  fprintf (hand,"global _draw_tile_%s%d%s\n",interlace?"i_":"",bpp,fname[flip]);
  fprintf (hand,"times ($$-$) & 3 db 0\n");
  fprintf (hand,"_draw_tile_%s%d%s:\n",interlace?"i_":"",bpp,fname[flip]);
  fprintf (hand,
    "\n"
    "push ebx\n"
    "push ecx\n"
    "push edx\n"
    "push esi\n"
    "push edi\n"
    "push ebp\n"
    "\n"

    "mov edi,[esp+28] ; edi is a pointer to the screen\n"
    "mov ebx,[esp+32]\n"
    "mov esi,[esp+36] ; esi is a pointer to the tilep\n"
    "mov ebp,[esp+40] ; ebp is a pointer to the palette\n"
  );

  if (flip&2)
  {
    fprintf (hand,"mov eax,ebx\n");
    fprintf (hand,"sal eax,3\n");
    fprintf (hand,"sub eax,ebx ; eax=pitch*7\n");
    fprintf (hand,"add edi,eax ; point to bottom line of tile dest\n");
    fprintf (hand,"neg ebx\n");
  }
  if (flip&1)
  {
    fprintf (hand,"add ebx,%d\n",8*depth_to_bytes(bpp));
    fprintf (hand,"add edi,%d\n",7*depth_to_bytes(bpp));
  }
  else
    fprintf (hand,"sub ebx,%d\n",8*depth_to_bytes(bpp));

  {
    int x,y;

//    fprintf (hand,"and cl,0x0f; Loop 8 times (till cl&0x80==0x80)\n");
//    fprintf (hand,"yloop_%d:\n",yloop_no);

    for (y=0;y<8;y++) // Unroll above loop
    {

//      fprintf (hand,"and cl,0xf0; Loop 4 times (till cl&0x04==0x04)\n");
//      fprintf (hand,"xloop_%d:\n",xloop_no);

      for (x=0;x<8;x++) // x<8 means Unroll above loop
      {
        // dl is tilep byte
        // eax is the colour we are going to draw
        // high bits of edx and ecx are currently unused

        if ((x&1)==0) fprintf (hand,"mov dl,byte[esi]; Get tile pixel\n");
        else          fprintf (hand,"rol dl,4        ; Get tile pixel\n");

        fprintf (hand,"mov al,dl\n");
        fprintf (hand,"and eax,0xf0 ; palette index now in bits 4-7 of eax\n");
        fprintf (hand,"test eax,0xf0\n");
        fprintf (hand,"jz trans_%.4x\n",label_no);
        fprintf (hand,"ror al,4\n");
        fprintf (hand,"mov eax,[ebp+eax*4] ; look up colour in palette\n");
        //fprintf (hand,"mov eax,0x%.8x\n", ((x<<2)<<11) | (y<<2) );

        if (bpp==8) fprintf (hand,"mov byte[edi],al\n");
        else if (bpp==15 || bpp==16)
                    fprintf (hand,"mov word[edi],ax\n");
        else if (bpp==24)
        {
          fprintf (hand,"mov byte[edi],al\ninc edi\nror eax,8\n");
          fprintf (hand,"mov byte[edi],al\ninc edi\nror eax,8\n");
          fprintf (hand,"mov byte[edi],al\nsub edi,2\n");
        }
        else if (bpp==32) fprintf (hand,"mov dword[edi],eax\n");

        fprintf (hand,"trans_%.4x:\n",label_no);

        if ((x&1)==1) fprintf (hand,"inc esi\n");

        fprintf (hand,"%s edi,%d\n",(flip&1)?"sub":"add",depth_to_bytes(bpp));

        label_no++;
      }

      if (interlace)
        fprintf (hand,"add esi,4 ; interlace mode\n");

//      fprintf (hand,"inc cl\n");
//      fprintf (hand,"test cl,0x04 ; Looped 4 times yet?\n");
//      fprintf (hand,"jz xloop_%d\n",xloop_no); xloop_no++;

      fprintf (hand,"add edi,ebx\n");

    }

//    fprintf (hand,"add cl,0x10\n");
//    fprintf (hand,"test cl,0x80 ; Looped 8 times yet?\n");
//    fprintf (hand,"jz yloop_%d\n",yloop_no);
//    yloop_no++;

  }

  fprintf (hand,
    "pop ebp\n"
    "pop edi\n"
    "pop esi\n"
    "pop edx\n"
    "pop ecx\n"
    "pop ebx\n"
    "xor eax,eax\n"
    "\n"
    "ret\n"
    "\n\n\n"
  );
  return 0;
}


int main()
{
  FILE *hand=NULL;
  static char outname[]="gra.asm";

  hand=fopen(outname,"wt");
  if (hand==NULL)
  {
    printf ("Couldn't open %s\n",outname);
    return 1;
  }

  fprintf (hand,
    "; Note - this file is automatically generated by mkgra.c\n\n"
    "bits 32\n"
    "section .text\n"
/*
    "global _dave_var\n"
    "_dave_var:\n"
    "dd 123\n"
    ";__memoryreadbyte  dd 0\n"
    ";__dreg            dd 0,0,0,0,0,0,0,0\n"
    "section .text\n"
    "bits 32\n"
    "top:\n"
    "\n"
    "global _daves_asm\n"
    "times ($$-$) & 3 db 0\n"
    "_daves_asm:\n"
    "\n"
    "push ebx\n"
    "push ecx\n"
    "push edx\n"
    "push esi\n"
    "push edi\n"
    "\n"
    "mov eax,[esp+24]\n"
    "mov ebx,dword[_dave_var]\n"
    "add eax,ebx\n"
    "\n"
    "pop edi\n"
    "pop esi\n"
    "pop edx\n"
    "pop ecx\n"
    "pop ebx\n"
    "\n"
    "ret\n"
    "\n"
*/
  );

  {
    static int dep[4]={8,16,24,32};
    int d,f,i;

    for (d=0;d<4;d++)
    {
      emit_clear_to_col(hand,dep[d]);
      for (i=0;i<2;i++)
      for (f=0;f<4;f++)
      {
        emit_draw_tile(hand,dep[d],f,i);
      }
    }
  }


  fclose(hand);
  return 0;
}