An 8086 PC emulator in 4043 bytes
The source itself: <a href="http://ioccc.org/2013/cable3/cable3.c" rel="nofollow">http://ioccc.org/2013/cable3/cable3.c</a><p>Or after running through preprocessing (not a huge help I found, sadly): <a href="https://gist.github.com/peterc/8259713" rel="nofollow">https://gist.github.com/peterc/8259713</a>