gistfile1.txt

sub msb(Int $self) {
    return Nil if $self == 0;
    return 0 if $self == -1;
    my $msb = 0;
    my $x = $self;
    $x = ($x + 1) * -2 if $x < 0;   # handle negative conversions
    while $x > 0xff   { $msb += 8; $x +>= 8; }
    if    $x > 0x0f   { $msb += 4; $x +>= 4; }
    if    $x +& 0x8   { $msb += 3; }
    elsif $x +& 0x4   { $msb += 2; }
    elsif $x +& 0x2   { $msb += 1; }
    $msb;
}

for (-1, -2, -3, -4) -> $n { say $n => msb($n); }
for (-126, -127, -128, -129) -> $n { say $n => msb($n); }