README.md

Intel 8086 CPU Emulator

An Intel 8086 CPU Emulator written in pure PHP.

Project Outlines

The project outlines as described in my blog post about Open Source Software Collaboration.

• The main purpose of this software is to emulate the Intel 8086 CPU using pure PHP.
• The features should not go beyond Intel's features and functions. So the features of this software are limited to those of the Intel 8086 CPU.
• This list is open. Feel free to request features.

Compile the BIOS

Run make bios/bios.

TTY

In order to have a TTY for the in- and output you can specify --tty <path>. This will start a socat subprocess to create an interface between PHP and TTY. The TTY then can be accessed using screen.

Optional, to use a different installation path for the socat binary you can specify --socat <path>.

1. Install socat.
2. Open a shell and run ./bin/screen.sh.
3. Open another shell and run ./bin/run.sh.

Terms

• Byte - 8 bit, one single character.
• Word - 16 bit, or 2 Byte.

8086 Resources

• Wikipedia: Intel 8086
• Wikipedia: Processor Register
• Wikipedia: FLAGS Register
• Wikipedia: Parity Flag
• Wikipedia: Word
• 8086 opcodes
• StackExchange: Emulate an Intel 8086 CPU
• x86 Registers
• Encoding x86 Instructions
• Encoding x86 Instruction Operands, MOD-REG-R/M Byte
• X86 Assembly/X86 Architecture
• X86-64 Instruction Encoding
• OUT -- Output to Port
• MDA, CGA, HGC, EGA, VGA, SVGA, TIGA (German)
• 8086/88 Assembler Befehlsreferenz (German)
• X86 Opcode and Instruction Reference
• Understanding Intel Instruction Sizes

More Resources

• How To Write a Computer Emulator