Asm

program asmDemo(input, output, stderr);

// The $asmMode directive informs the compiler
// which syntax is used in asm-blocks.
// Alternatives are 'att' (AT&T syntax) and 'direct'.
{$asmMode intel}

var
    n, m: longint;
begin
    n := 42;
    m := -7;
    writeLn('n = ', n, '; m = ', m);
    
    // instead of declaring another temporary variable
    // and writing "tmp := n; n := m; m := tmp;":
    asm// eax := n// xchg can only operate at most on one memory address// swaps values in eax and at m// n := eax (holding the former m value)// an array of strings after the asm-block closing 'end'// tells the compiler which registers have changed// (you don't wanna mess with the compiler's notion// which registers mean what)
        mov eax, n  // eax := n
        // xchg can only operate at most on one memory address
        xchg eax, m // swaps values in eax and at m
        mov n, eax  // n := eax (holding the former m value)
    // an array of strings after the asm-block closing 'end'
    // tells the compiler which registers have changed
    // (you don't wanna mess with the compiler's notion
    // which registers mean what)
    END ['eax'];
    
    writeLn('n = ', n, '; m = ', m);
end.

program sign(input, output, stderr);

type
    signumCodomain = -1..1;

{ returns the sign of an integer }
function signum({$ifNDef CPUx86_64} const {$endIf} x: longint): signumCodomain;
{$ifDef CPUx86_64} // ============= optimized implementation
assembler;
{$asmMode intel}
asm// ensure result is not wrong// due to any residue// x ≟ 0// al ≔ ¬ZF// propagate sign-bit through reg.// if SF then rax ≔ −1
    xor rax, rax                  // ensure result is not wrong
                                  // due to any residue
    
    test x, x                     // x ≟ 0
    setnz al                      // al ≔ ¬ZF
    
    sar x, 63                     // propagate sign-bit through reg.
    cmovs rax, x                  // if SF then rax ≔ −1
END;
{$else} // ========================== default implementation
begin
    // This is what math.sign virtually does.
    // The compiled code requires _two_ cmp instructions, though. 
    if x > 0 then
    begin
        signum := 1;
    end
    else if x < 0 then
    begin
        signum := -1;
    end
    else
    begin
        signum := 0;
    end;
end;
{$endIf}

// M A I N =================================================
var
    x: longint;
begin
    readLn(x);
    writeLn(signum(x));
end.