Opcode Descriptions and Examples
PHP Manual

ECHO

PHP code

<?php
/*
 * Dump text
 * opcode number: 40
 */
echo "hello world";
?>

PHP opcodes

Function name: (null)

Compiled variables: none

line#op fetchextreturn operands
60 ECHO     'hello+world'
71 RETURN     1

Opcode Descriptions and Examples
PHP Manual