The program bochs is a highly portable open source x86 PC emulator
written in C++, and runs on most popular platforms.  It includes
emulation of the Intel x86 CPU, common IO devices, and a custom
BIOS.  Currently, bochs can be compiled to emulate a 386, 486,
Pentium, Pentium PRO or AMD64 CPU.

Bochs is capable of running most operating systems inside the
emulation including Linux, NetBSD, Windows 95, DOS, and Windows NT 4.

Homepage:
https://bochs.sourceforge.net/
