Opcode Descriptions and Examples
PHP 手册

BOOL_NOT

PHP code

<?php
/*
 * Boolean (logical) not of "value"
 * opcode number: 13
 */
echo !1;
?>

PHP opcodes

Function name: (null)

Compiled variables: none

line#op fetchextreturn operands
60 BOOL_NOT   ~0 1
 1 ECHO     ~0
72 RETURN     1

Opcode Descriptions and Examples
PHP 手册