Awesome

jsbochs - Bochs PC Emulator for the Browser

Emscripten "port" to Javascript of the Bochs PC Emulator.

Inspired by Fabrice Bellard's fantastic jslinux.

Status

The code runs flawlessly under javascript. The only issue is that it runs SLOOOOW. It runs the BIOS code reasonably fast, but then goes down to 0.04MIPS instead of native 30MIPS.

Also, I have almost no output options yet.

This git repo is currently my work bench and a bastadization of the original bochs code. I have removed all files that were not absolutely necessary for compilation in order to get my bearings.

Suggestions for Performance

-s PRECISE_I64_MATH=0 will likely not work. I am very concerned that doubles > 2^32 may not be monotonic when adding 1.
-s INLINING_LIMIT=0 compiles very slowly. But I will try to get it compiled (>1h)
replace 64bit ints with 32bit. Not sure what to replace the instruction counter with since 32bit counter will overflow in (2^32instructions/30,000,000instructions/s/60s =) 2.5 minutes. I will try a clock divider since I don't need instruction-precise timers anyway.

Install

Requirements

llvm
emscripten
possibly node

Building

Simply run the build_it.sh script which will configure and build the bochs.js file.

Alternatively follow the steps below:

<pre> emconfigure ./configure --disable-plugins --disable-x86-64 --enable-cpu-level=4 \ --with-term --disable-large-ramfile --disable-cdrom --disable-debugger-gui \ --disable-readline --disable-iodebug --enable-show-ips --enable-logging \ --disable-idle-hack --disable-debugger --disable-disasm --enable-fpu emmake make emcc -O1 bochs.bc -o bochs.js node launch.js </pre>

TODO

Currently it runs under node in the console. Get main loop running for browser
Get an output running. Either a nicer terminal output or SDL output in the browser
Get it to compile with -O2. This would be a tremendous speedup, but currently there are compiler errors about bit arithmetic.

Issues

Resolved Issues

Open Issues

Browser main loop
Compile with closure (bit arithmetic errors)
Speed

License

Bochs (and jsbochs) as a whole is released under the GNU Lesser General Public License
Parts of Bochs have specific licenses which are compatible with the GNU Lesser General Public License. Hence each source file contains its own licensing information.