Does php have a virtual machine?

PHP Virtual Machine

Virtual machines are also computers. Referring to the design of a physical machine, when designing a virtual machine, you should first consider three elements: Instructions, data storage, function stack frames;

Instructions (Recommended learning: PHP video tutorial)

Instructions are composed of opcodes and operands ;The opcode specifies the operation type of this instruction, and the operand specifies the operand itself or the address of the operand;

Data storage

PHP virtual machine supports multiple data types : Integer, floating point, string, array, object, etc.;

Function stack frame

PHP virtual machine implements a function stack frame similar to that of a physical machine Structure;

Use _zend_vm_stack to represent the stack structure; use the prev field between multiple stacks to form a one-way linked list; top and end point to the low and top of the stack, respectively, and are pointers of zval type;

Summary

The PHP virtual machine is also a computer. There are three points that we need to focus on: instruction set (including instruction processing functions), data storage (zval), and function stack frame ;

At this time, the virtual machine can accept instructions and execute the instruction code;

However, the PHP virtual machine is dedicated to executing PHP code. How can the PHP code be converted into a PHP virtual machine? What about the instructions that can be recognized - compilation;

The PHP virtual machine also provides a compiler, which can convert the PHP code into a set of instructions that can be recognized;

Theory You can customize any language. As long as you implement a compiler that can convert your own language into instruction codes that PHP can recognize, it can be executed by the PHP virtual machine;

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