gmp_com

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

gmp_com — Calculates 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、int 或 string，可以按照跟在 gmp_init() 中使用字符串并自动检测 base（即当 base 等于 0 时）相同的逻辑将其解释为数字。

返回值

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

示例

示例 #1 gmp_com() example

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

以上示例会输出：

-1235

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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)