decoder.c

win32program disassembler

   else r=databody(c);
   return r;
}
int databody(int c)
{
         if(c==1) return labeldata();
   else if (c==2) return bytex();
   else if (c==3) return byte();
   else if (c==4) return pascalstring();
   else if (c==5) return nullstring();
   else if (c==6) return worddata();
   else return 0;
}
int labeldata()
{
int r;
   r = dword();
   m_dword=result;
   return r;
}
int worddata()
{
int r;
   r = word();
   m_dword=result;
   return r;
}
int instructionbody()
{
int r;
   if (PeekOneByte()!=0x0F) 
               { r=onebyteinstr(); opclass=1; return r;} 
   else {byte(); r=twobyteinstr(); opclass=2; return r;}
}
int byte()
{
int x;
   x=ReadOneByte();
   if(printMode==1)printf("%02X", x);else;
   a_loc++;  i_col++;  result=x;
   return 1;
}
int bytex()
{
int x;
   x=ReadOneByte();
   m_byte=x;                                                                             
   a_loc++;  i_col++;  result=x;
   return 1;
}
int op()
{
int x;
   x=ReadOneByte();
   if(printMode==1)printf("%02X", x);else;
   a_loc++;  i_col++;  result=x;
   return 1;
}
int pascalstring()
{
int i, n, x;
    x=ReadOneByte();
    //if(printMode==1)printf("%02X ", x);else;
    a_loc++; i_col++; result=x;
    stringBuf[0]=x;      
    n=x;
    for(i=1;i<n+1;i++)
    { x=ReadOneByte(); //if(printMode==1)printf("%02X ", x);else; 
    a_loc++; i_col++; result=x; stringBuf[i]=x;}
    return 1;
}
int nullstring()
{
int i, x;
    i=0;
    while(1)
    { x=ReadOneByte(); //if(printMode==1)printf("%02X ", x);else; 
    a_loc++; i_col++; result=x; stringBuf[i++]=x; if(!isprint(PeekOneByte()))break;}
    while(getMap(cur_position+i_col)==0x08)
    {
        x=ReadOneByte(); //if(printMode==1)printf("%02X ", x);else; 
        stringBuf[i++]=x; a_loc++; i_col++; 
    }
    stringBuf[i]=-1;
    return 1;
}
int word()
{
int x,y;
   byte(); x=result;
   byte(); y=result;
   result=y*256+x;
   return 1;
}
int dword()
{
int x1,x2,x3,x4;
   byte(); x1=result;
   byte(); x2=result;
   byte(); x3=result;
   byte(); x4=result;
   result=((x4*256+x3)*256+x2)*256+x1;
   return 1;
}
int adword()
{
   if (addressOveride) return word(); else return dword();
}
int wdword()
{
   if (operandOveride) return word(); else return dword();
}
int pword()
{
int r;
   r=word();  if (!r) return 0; i_word=result;
   r=dword(); if (!r) return 0; i_dword=result;
   return 1;
}   
int prefixes()
{
int r;
   if (opcodeTable[PeekOneByte()]==PREFIX)
   {
      r=op(); if (!r) return 0; 
      prefixStack[i_psp++]=result;
      if (result==102) operandOveride=1;
      if (result==103) addressOveride=1;
      return 1;
   }
   else return 0;
}
int onebyteinstr()
{
int r, b, x, y, y1, y2;
   b=PeekOneByte();
   //fprintf(stderr, "b=%02X",b),getch();
   switch(opcodeTable[b])
   {
      case  0: r=op();     if(!r) return 0; x=result; 
               //fprintf(stderr, "x=%02X",x),getch();
               i_opclass=0; i_opcode=x;                
               break;
      case  1: r=op();     if(!r) return 0; x=result; 
               r=byte();   if(!r) return 0; y=result;
               i_opclass=1; i_opcode=x; i_byte=y;      
               break;
      case  2: r=op();     if(!r) return 0; x=result;
               r=word();   if(!r) return 0; y=result;
               i_opclass=2; i_opcode=x; i_word=y;      
               break;
      case  3: r=op();     if(!r) return 0; x=result;
               r=word();   if(!r) return 0; y1=result;
               r=byte();   if(!r) return 0; y2=result;
               i_opclass=3; i_opcode=x; i_word=y1; i_byte=y2; 
               break;
      case     4: r=op();     if(!r) return 0; x=result;
               r=wdword(); if(!r) return 0; y=result;
               i_opclass=4; i_opcode=x; i_dword=y;
               break;
      case 44: r=op();     if(!r) return 0; x=result;
               r=adword(); if(!r) return 0; y=result;
               i_opclass=4; i_opcode=x; i_dword=y;
               break;
      case  5: r=op();     if(!r) return 0; x=result;
               r=pword();  if(!r) return 0; 
               i_opclass=5; i_opcode=x; 
               break;
      case  6: r=op();     if(!r) return 0; x=result;
               r=modrm();  if(!r) return 0; 
               i_opclass=6; i_opcode=x; 
               break;
      case  7: r=op();     if(!r) return 0; x=result;
               r=modrm();  if(!r) return 0;
               r=byte();   if(!r) return 0; y=result;
               i_opclass=7; i_opcode=x; i_byte=y; 
               break;
      case  8: r=op();     if(!r) return 0; x=result;
               r=modrm();  if(!r) return 0;
               r=wdword(); if(!r) return 0; y=result;
               i_opclass=8; i_opcode=x; i_dword=y; 
               break;
      case  9: r=op();     if(!r) return 0; x=result;
               r=opext();  if(!r) return 0;
               i_opclass=9; i_opcode=x;  
               break;
      case 10: r=op();     if(!r) return 0; x=result;
               r=opext();  if(!r) return 0;
               r=byte();   if(!r) return 0; y=result;
               i_opclass=10; i_opcode=x; i_byte=y; 
               break;
      case 11: r=op();     if(!r) return 0; x=result;
               r=opext();  if(!r) return 0;
               r=wdword(); if(!r) return 0; y=result;
               i_opclass=11; i_opcode=x; i_dword=y; 
               break;
      case 12: r=op();     if(!r) return 0; x=result;
               r=opextg(); if(!r) return 0;
               i_opclass=12; i_opcode=x;  
               break;
      case 13: r=op();     if(!r) return 0; x=result; // case jump block
               b=PeekOneByte();
               if (b==36) 
               { 
                  b=PeekSecondByte();
                  if (rmTable[b]==5)
                  {
                     r=op(); if(!r) return 0; y1=result;
                     r=op(); if(!r) return 0; y2=result;
                     i_opclass=13;
                     i_opcode=x;
                     i_mod=y1;
                     i_sib=y2;
                     r=labelstartposition(); if(!r) return 0;
   // ..................................................................            
                     if (nextMode) 
                     {
                        r=label1(); 
                        finished=1;
                        if(!r) return 1;   // need to be careful ...
                     }
                     return 1;
                  }
               }
               //else
               {
                  b=PeekOneByte();
                  if (regTable[b]<7)
                  {
                     r=opext(); if(!r) return 0;
                     i_opclass=13; i_opcode=x;
                  }
                  else return 0;
               }
               break;
      case 14: r=op();     if(!r) return 0; x=result; // test group
               if (x==246)
               {
                  b=PeekOneByte();
                  if (regTable[b]==0)
                  {
                     r=opext();   if(!r) return 0;
                     r=byte();    if(!r) return 0; y=result;
                     i_opclass=14; i_opcode=x; i_byte=y;
                  }
                  else if (regTable[b]>1)
                  {
                     r=opext();   if(!r) return 0;
                     i_opclass=14; i_opcode=x;
                  }
                  else return 0;
               }
               else
               {
                  b=PeekOneByte();
                  if (regTable[b]==0)
                  {
                     r=opext();   if(!r) return 0;
                     r=wdword();    if(!r) return 0; y=result;
                     i_opclass=14; i_opcode=x; i_dword=y;
                  }
                  else 
                  {
                     r=opext();   if(!r) return 0;
                     i_opclass=14; i_opcode=x;
                  }
               }
               break;