gmp_com

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

gmp_comCalculates one's complement

说明

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

Returns the one's complement of num.

参数

num

GMP 对象或 int ,或数字string

返回值

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

范例

Example #1 gmp_com() example

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

以上例程会输出:

-1235

User Contributed Notes

xo at jdbartlett dot com 13-Apr-2010 10:07
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)