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https://github.com/nepx/halfix
x86 PC emulator that runs both natively and in the browser, via WebAssembly
https://github.com/nepx/halfix
c c99 cpu-emulator emscripten emulator javascript pc-emulator pentium webassembly x86 x86-emulator
Last synced: 6 days ago
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x86 PC emulator that runs both natively and in the browser, via WebAssembly
- Host: GitHub
- URL: https://github.com/nepx/halfix
- Owner: nepx
- License: gpl-3.0
- Created: 2019-10-26T16:46:51.000Z (about 5 years ago)
- Default Branch: master
- Last Pushed: 2022-12-26T04:29:19.000Z (almost 2 years ago)
- Last Synced: 2024-10-12T17:21:04.662Z (24 days ago)
- Topics: c, c99, cpu-emulator, emscripten, emulator, javascript, pc-emulator, pentium, webassembly, x86, x86-emulator
- Language: C
- Homepage: https://nepx.github.io/halfix-demo/
- Size: 2.29 MB
- Stars: 671
- Watchers: 19
- Forks: 87
- Open Issues: 21
-
Metadata Files:
- Readme: readme.md
- License: LICENSE
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README
# Halfix x86 emulator
Halfix is a portable x86 emulator written in C99. It allows you to run legacy operating systems on modern platforms.
## Why?
I made this mostly for fun, and because it was a great way to learn about the x86 PC architecture. On a more practical level, it can be used for:
- Testing out or developing operating systems
- Running old programs or operating systems that no longer work on modern computers or you wouldn't want to risk running on your personal computer.
- Simulating other x86-based systems (the CPU component can be isolated relatively easily and used in other projects)
- Testing web browser performance
## Building and Running
You will need `node.js`, a C99-compatible compiler, `zlib`, and Emscripten (only if you're targeting the browser). Make sure that the required libraries are in a place where the compiler can find them. No pre-build configuration is required.
The display driver uses `libsdl`, but if you're on Windows, there's a native port that uses the Win32 API and doesn't require SDL.
```bash
# Debug, native
node makefile.js
# Debug, Emscripten, asm.js
node makefile.js emscripten
# Debug, Emscripten, WebAssembly
node makefile.js emscripten --enable-wasm
# Release, native
node makefile.js release
# Release, Emscripten, asm.js
node makefile.js emscripten release
# Release, Emscripten, WebAssembly
node makefile.js emscripten --enable-wasm release
# Win32 API build (no SDL required)
node makefile.js win32
# Win32 API build, release
node makefile.js win32 release
# For more options and fine tuning
node makefile.js --help
# Chunk an image
node tools/imgsplit.js os.img
# Run in browser
http-server
```
Check the [project wiki](https://github.com/nepx/halfix/wiki) for more details.
## System Specifications
- [CPU](https://github.com/nepx/halfix/tree/master/src/cpu): x86-32 (FPU, MMX, SSE, SSE2, some SSE3, PAE)
- RAM: Configurable - anywhere from 1 MB to 3584 MB
- Devices:
- Intel 8259 [Programmable Interrupt Controller](https://github.com/nepx/halfix/blob/master/src/hardware/pic.c)
- Intel 8254 [Programmable Interval Timer](https://github.com/nepx/halfix/blob/master/src/hardware/pit.c)
- Intel 8237 [Direct Memory Access Controller](https://github.com/nepx/halfix/blob/master/src/hardware/dma.c)
- Intel 8042 ["PS/2" Controller](https://github.com/nepx/halfix/blob/master/src/hardware/kbd.c) with attached keyboard and mouse
- [i440FX chipset](https://github.com/nepx/halfix/blob/master/src/hardware/pci.c) (this doesn't work quite so well yet)
- 82441FX PMC
- 82371SB ISA-to-PCI bus
- 82371SB IDE controller
- [ACPI](https://github.com/nepx/halfix/blob/master/src/hardware/acpi.c) interface
- Intel 82093AA [I/O APIC](https://github.com/nepx/halfix/blob/master/src/hardware/ioapic.c)
- Display: Generic [VGA graphics card](https://github.com/nepx/halfix/blob/master/src/hardware/vga.c) (ET4000-compatible) with Bochs VBE extensions, optionally PCI-enabled
- Mass Storage:
- Generic [IDE controller](https://github.com/nepx/halfix/blob/master/src/hardware/ide.c) (hard drive and CD-ROM)
- Intel 82077AA [Floppy drive controller](https://github.com/nepx/halfix/blob/master/src/hardware/fdc.c) (incomplete, but works in most cases)
- Dummy PC speaker (no sound)
## Compatibility
It boots a wide range of operating system software, including all versions of DOS, most versions of Windows (excluding Windows 8), newer versions of OS/2 Warp (3 and 4.5), ReactOS, some varieties of Linux (ISO Linux, Damn Small Linux, Red Star OS 2, Buildroot, Ubuntu), 9Front, NeXTSTEP, several hobby OSes, and probably more.
See [Compatibility](compatibility.md) for more details.
## Self-Virtualization
Can you run the emulator inside the emulator?
Yes, but not very quickly.
## Screenshots
MS-DOS
OS/2 Warp 4.5
Windows Vista
Windows 7
The same Windows 98 disk image as in the [Halfix in Halfix screenshot](docs/pics/halfix-in-halfix.png) running in Firefox
CPU-Z on Windows XP
Windows 10
Ubuntu
## Transferring Files
Create a directory with all the files you want to transfer and create an ISO image.
```
mkisofs -o programs.iso -max-iso9660-filenames -iso-level 4 programs/
```
Now update the configuration file as follows:
```
# Note: it does not hae to be ata0-slave.
# I have not tested it with anything but ata0-slave.
[ata0-slave]
inserted=1
type=cd
file=/tmp/programs.iso
driver=sync
```
Now boot up your operating system and copy the files from the CD-ROM to the hard drive.
## Known Issues
- SSE3 is not fully supported
- Performance isn't terrible, but it isn't fantastic either (70-100 MIPS native, 10-30 MIPS browser)
- Timing is completely off
- Windows 8 doesn't boot (see [this issue](https://github.com/nepx/halfix/issues/1))
- FPU exceptions are probably very incorrect
- Most devices aren't complete, but enough is implemented to boot modern OSes.
- The configuration file parser isn't very good
## License
GNU General Public License version 3
## Similar Projects
- [v86](https://www.github.com/copy/v86)
- [JSLinux](http://bellard.org/jslinux/)
- [jemul8](http://www.github.com/asmblah/jemul8)
## Credits
The FPU emulator uses an modified version of [Berkeley SoftFloat](jhauser.us/arithmetic/SoftFloat.html) from the [Bochs](bochs.sourceforge.net) emulator.