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 // 실메모리의 크기를 구한다.
    
 // 메모리는 512메가부터 2기가 바이트까지 뒤진다.
 for( nSize = nI = 512; nI < 2048; nI++ )
 {
  pX = (UCHAR*)( nI * (ULONG)0x100000 );  //  nl * 1MB
  

  byTe = pX[0];         // The start address of the memory.
  byTe++;                 // Increasing the value of the start address.
  pX[0] = byTe;        // Writting the value on the start address.
  if( byTe != pX[0] )  // Comparing between the increased data and the value of the start address.
   break;                  // If it's not the same, there is no memory on that address.
  else
   nSize++;              // If it's the same, there is memory. Keep calculating.
        
        pX[0] -= 1;     // Restoring to the previous value
 }

 return( nSize * 0x100000 );  // 바이트 단위로 리턴한다.
}

// allocate one physical page
 DWORD dwAllocPhysPage()
{
 int  nI;
 UCHAR *pTbl;

 pTbl = bell.pPhysRefTbl; // Physical Memory Management Table

 // search after 64K
 for( nI = 16; nI < bell.nPhysRefSize; nI++ )
 {
  // if the address is video memory then next search is started at 1.5M( = 0x180000 ) area
  if( nI == ( (int)0xA0000 / 4096 ) ) // Skipping the space of ROM BIOS.
   nI = ( (int)0x180000 / 4096 );

  if( pTbl[nI] == 0 )
  {
   pTbl[nI]++;  // increase counter
   return( (DWORD)( (DWORD)nI * (DWORD)4096 ) );
  }
 }
 return( 0 ); // allocation failed
}

 int nFreePage( DWORD dwPhysAddr )
{
 DWORD dwI;
 UCHAR *pTbl;

 dwI = (DWORD)( dwPhysAddr / (DWORD)4096 );

 pTbl = bell.pPhysRefTbl;
 if( pTbl[dwI] == 0 )
  return( -1 );   // 할당되지 않은 메모리이다.

 pTbl[dwI]--;  // Decreasing the counter value with 1

 return( 1 );
}