gmp_com

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

gmp_com — Calculates one's complement

Beschreibung

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

Returns the one's complement of num.

Parameter-Liste

num: Ein GMP-Object, ein Integer oder eine numeriche Zeichenkette.

Rückgabewerte

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

Beispiele

Beispiel #1 gmp_com() example

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

Das oben gezeigte Beispiel erzeugt folgende Ausgabe:

-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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