ianopolous / jpc

JPC - The fast x86 PC emulator in 100% pure Java

JPC

The fast x86 PC emulator in 100% pure Java

JPC is a fast modern x86 PC emulator capable of booting Windows up to Windows 95 (and windows 98 in safe mode) and some graphical linuxes. It has a full featured graphical debugger with time travel mode along with standard features like break and watch points.

Running

To get started with JPC just run it with:
java -jar JPCApplication.jar -boot hda -hda yourdiskimage.img

or get a list of options by running:
java -jar JPCApplication.jar -help

Building

To build JPC run:
make application

To build the debugger run:
make debugger

To run some dos games easily, put them in a directory on your real computer and use JPC's ability to view a directory tree as a virtual FAT32 drive. For example, if some games are in "dosgames" in the directory where you expanded all the JPC files then type:
java -jar JPCApplication.jar -boot fda -fda resources/images/floppy.img -hda dir:dosgames
This won't save any writes you make to the virtual FAT32 drive. If you would like to sync write to the underlying files, run with -hda dir:sync:dosgames

Debugger

The JPC debugger allows you to run x86 code step by step, use breakpoints, memory watchpoints, directly view the memory, cpu state etc in a nice colourful GUI. Once you've set your disks in the debugger (you can pass command line options identical to the Application or just use the menus), click "create new pc" in the File menu. Then to start execution click "start" in the run menu.

Credits

• The BIOS used in JPC is the Bochs BIOS; see http://bochs.sourceforge.net/
• The VGA BIOS used in JPC is the Plex86/Bochs LGPL'd bios; see http://www.nongnu.org/vgabios
• The test Floppy image "floppy.img" is from the Odin FreeDOS project; see http://odin.fdos.org/

History

The JPC project was originally started in the Particle Physics department of Oxford university by Dr Rhys Newman and Dr Jeff Tseng. The original team included Chris Dennis, Ian Preston, Mike Moleschi and Guillaume Kirsch. The current team includes Ian Preston and Kevin O'Dwyer.

jpc's Issues

Exception in thread main error in Ubuntu 20.04 Focal Fossa.

I'm trying to make a program that uses your emulator to emulate Windows 95.

But on Ubuntu 20.04 Focal Fossa, I get this error message:

Exception in thread "main" java.lang.IllegalStateException at org.jpc.j2se.JPCApplication.getResources(JPCApplication.java:593) at org.jpc.j2se.JPCApplication.<init>(JPCApplication.java:205) at org.jpc.j2se.JPCApplication.main(JPCApplication.java:766)

How do I fix this?

SeaBIOS won't execute (unimplemented opcode that should exist)

The opcodes sgdt and pause are unimplemented, so JPC fails when starting SeaBIOS Git or 1.10.2 with an UnimplementedOpcodeException. However, I do see code for sgdt at least.

I was able to workaround pause by changing it in code to nop, but what is wrong with sgdt?

Large difference with code from http://jpc.sourceforge.net, even though that page links here

The code available for JPC on SourceForge seems more in line with the "Beautiful Architecture" article describing the project. Especially interesting there is the optimising compiler, which does not seem to be implemented in the project on GitHub.

Is there a reason for this huge difference in the two code bases? Does the project here on GitHub perform as well as the SourceForge project even though it only seems to do interpretation?

Sorry for making an issue here, I couldn't find a better place to ask this question. I am interested in emulating a different type of processor, and I'm wondering whether I should base myself on the GitHub or SourceForge source code.

[3.0] Menu issues (problem with changing disks, there's no disk eject)

Steps to reproduce:

1. Start JPC
2. Wait for FreeDOS to boot
3. Change floppy disk to another image
4. Reset

What should happened:
New image should boot.

What happens:
Menu shows new disk image inserted, but instead FreeDOS is booted again.

Feature request: possibility of ejecting disks (floppy/hd/cdrom) from menu.

IBM PC-DOS 2.10 (5.25) doesn't boot in 2.4.1/3.0 and causes memory leak in 3.0

IBM PC-DOS 2.10 (5.25) from https://winworldpc.com/product/pc-dos/2x

2.4.1 - DOS 2.1 doesn't boot
3.0 - as above, plus memory leak

Good job!

Just dies with exception on Win10

G:\games\JPC\JPC-3.0>java -jar JPCApplication.jar -boot fda -fda resources/images/floppy.img
ьрЁ. 05, 2023 3:24:03 PM org.jpc.j2se.JPCApplication main
INFO: Using configuration specified on command line
Exception in thread "main" java.lang.IllegalStateException
at org.jpc.j2se.JPCApplication.getResources(JPCApplication.java:593)
at org.jpc.j2se.JPCApplication.(JPCApplication.java:205)
at org.jpc.j2se.JPCApplication.main(JPCApplication.java:766)

G:\games\JPC\JPC-3.0>java -version
java version "17.0.5" 2022-10-18 LTS
Java(TM) SE Runtime Environment (build 17.0.5+9-LTS-191)
Java HotSpot(TM) 64-Bit Server VM (build 17.0.5+9-LTS-191, mixed mode, sharing)