gmp_com

    (PHP 4 >= 4.0.4, PHP 5, PHP 7, PHP 8)

    gmp_com — Calculates one's complement

    Description

    gmp_com(GMP|int|string $num): GMP

    Returns the one's complement of num.

    Parameters

    num

    A GMP object, an int or a numeric string.

    Return Values

    Returns the one's complement of num, as a GMP number.

    Examples

    Example #1 gmp_com() example

    <?php
    $com     = gmp_com("1234");
    echo     gmp_strval($com) . "\n";
    ?>

    The above example will output:

    -1235

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    User Contributed Notes 1 note

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    xo at jdbartlett dot com
    14 years ago
    If you're using one's compliment (bitwise NOT) to flip all $a's bits, don't forget that you need to use a mask to specify how many bits you expect in your result:

    <?php gmp_and(gmp_com('1234'), '2047') ?>
    >> 813 // 01100101101 in binary

    I chose 2047 because 1234 is an 11-bit binary number and 2047 is the maximum an 11-bit register can hold:

    11111111111 (2047)
    10011010010 (1234)
    01100101101 (813)
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