What is Softx86?
Softx86 is a library that provides software emulation of an Intel 80x86 CPU. The library takes care of executing opcodes and handling exceptions while the host application is responsible for providing simulated RAM, I/O devices, and external signals such as NMI and hardware interrupts.
Will Softx86 become an entire PC emulator?
No. The Softx86 library is designed to emulate the CPU and the CPU only. The program using the library is responsibile for emulating external hardware connected to the CPU. While that may sound harsh, it allows the use of the library to emulate any platform (either real or hypothetical) that makes use of the 80x86.
What else does Softx86 do?
Softx86 also provides callbacks and an API that the host application can use to function both as an emulator and a debugger.
Where can I get it?
You can find it on SourceForge.