Load a 16-bit DLL into a 32-bit Process on Windows 7 64-bit

Question

I wrote a 32-bit application that launches a 16-bit executable, which loads some 16-bit DLLs to perform some of the application's functions. It runs fine on Windows 7 32-bit, but not on Windows 7 64-bit since that version of the OS does not include the NTVDM.

The 16-bit portion of the code is pretty extensive and would be pretty expensive to port to 32-bit. Also, it uses some 3rd-party 16-bit APIs from a company that is no longer in business; therefore, that code would have to be recreated completely, thereby increasing the cost.

Is there any possible way to simply load the existing 16-bit DLLs directly from the 32-bit application, removing the 16-bit executable completely?

I've looked into thunking, but it doesn't appear that is supported in Windows 7 either.

Answer 1

You have to use an emulator or a virtual machine.

Or, if that is not an option then you can write a primitive emulator yourself, read the machinecode instruction-by-instruction and modify fake-registers and memory accordingly, and when the program calls outward then you will have to generate responses.

Answer 2

No. This is not possible in Windows.