internal void DoSquare( Integer ToSquare )
{
if( ToSquare.GetIndex() == 0 )
{
ToSquare.Square0();
return;
}
if( ToSquare.GetIndex() == 1 )
{
ToSquare.Square1();
return;
}
if( ToSquare.GetIndex() == 2 )
{
ToSquare.Square2();
return;
}
// Now Index is at least 3:
int DoubleIndex = ToSquare.GetIndex() << 1;
if( DoubleIndex >= Integer.DigitArraySize )
{
throw( new Exception( "Square() overflowed." ));
}
for( int Row = 0; Row <= ToSquare.GetIndex(); Row++ )
{
if( ToSquare.GetD( Row ) == 0 )
{
for( int Column = 0; Column <= ToSquare.GetIndex(); Column++ )
M[Column + Row, Row] = 0;
}
else
{
for( int Column = 0; Column <= ToSquare.GetIndex(); Column++ )
M[Column + Row, Row] = ToSquare.GetD( Row ) * ToSquare.GetD( Column );
}
}
// Add the columns up with a carry.
ToSquare.SetD( 0, M[0, 0] & 0xFFFFFFFF );
ulong Carry = M[0, 0] >> 32;
for( int Column = 1; Column <= DoubleIndex; Column++ )
{
ulong TotalLeft = 0;
ulong TotalRight = 0;
for( int Row = 0; Row <= Column; Row++ )
{
if( Row > ToSquare.GetIndex() )
break;
if( Column > (ToSquare.GetIndex() + Row) )
continue;
TotalRight += M[Column, Row] & 0xFFFFFFFF;
TotalLeft += M[Column, Row] >> 32;
}
TotalRight += Carry;
ToSquare.SetD( Column, TotalRight & 0xFFFFFFFF );
Carry = TotalRight >> 32;
Carry += TotalLeft;
}
ToSquare.SetIndex( DoubleIndex );
if( Carry != 0 )
{
ToSquare.SetIndex( ToSquare.GetIndex() + 1 );
if( ToSquare.GetIndex() >= Integer.DigitArraySize )
throw( new Exception( "Square() overflow." ));
ToSquare.SetD( ToSquare.GetIndex(), Carry );
}
}
