Eine BigInt Klasse + RSA-Beispiel

[negaH]

Delphi-Quellcode:

function DoAddC(Digits: Pointer; Value: Cardinal; Count: Integer): Cardinal; 
asm
         
         LEA EAX,[EAX + ECX]
         NEG ECX
         ADD [EAX + ECX],EDX
         MOV EDX, 0
         JMP @@2 
@@1:     ADC [EAX + ECX],EDX
@@2:     JNC @@3
         INC ECX
         JNZ @@1
@@3:     ADC EDX,EDX
         MOV EAX,EDX
end;

procedure TBigInt.Add(Value: Cardinal);
var
  Carry: Cardinal;
begin
  Carry := DoAddC(@FDigits, Value, Length(FDigits));
  if Carry <> 0 then
  begin
    SetLength(FDigits, Length(FDigits) +1);
    FDigits[High(FDigits)] := Carry;
  end;
end;

Gruß Hagen