Сложение и вычитание двух целых чисел в дополнительном коде

type
    TBinNumb = String[8];
    TMax = -63..63;
    TInt = -127..127;
 
function BinToDec(const s: TBinNumb): TInt;
var
    Result: TInt;
    i, n: 1..8;
begin
    Result := 0; n := Length(s);
    for i := 1 to n do
        Inc(Result, Round(Ord(s[i] = '1') * Exp(Ln(2) * (n - i))));
    BinToDec := Result;
end;
 
function DecToBin(x: TInt): TBinNumb;
var
    Result: TBinNumb;
begin
    Result := '';
    repeat
        Result := Chr(48 + Ord(x mod 2 <> 0)) + Result;
        x := x div 2;
    until (x = 0);
    while (Length(Result) < 7) do
        Result := '0' + Result;
    DecToBin := Result;
end;
 
function AdditionalToDec(const s: TBinNumb): TInt;
var
    Result: TInt;
    ss: TBinNumb;
    i, n: 1..8;
begin
    if (s[1] = '1')
    then
    begin
        ss := Copy(s, 2, Length(s) - 1);
        for i := 1 to Length(ss) do
            ss[i] := Chr(48 + Ord(ss[i] = '0'));
        Result := -BinToDec(ss) - 1;
    end
    else
        Result := BinToDec(s);
    AdditionalToDec := Result;
end;
 
function DecToAdditional(x: TInt): TBinNumb;
var
    Result: TBinNumb;
    flag: Boolean;
    i: 1..8;
begin
    if (x < 0)
    then
    begin
        Result := DecToBin(Abs(x));
        for i := 1 to Length(Result) do
            Result[i] := Chr(48 + Ord(Result[i] = '0'));
        i := Length(Result);
        repeat
            if (Result[i] = '1')
            then
                Result[i] := '0'
            else
                Result[i] := '1';
            flag := (Result[i] = '1');
            Dec(i);
        until ((flag) Or (i <= 1));
        Result := '1' + Result;
    end
    else
        Result := '0' + DecToBin(x);
    DecToAdditional := Result;
end;
 
var
    x, y: TBinNumb;
begin
    ReadLn(x); ReadLn(y);
    WriteLn('   Сумма: ', DecToAdditional(AdditionalToDec(x) + AdditionalToDec(y)));
    WriteLn('Разность: ', DecToAdditional(AdditionalToDec(x) - AdditionalToDec(y)));
end.