Hi all,
My problem is that i have a BIG DOS4GW Application running under Win2k or WinXp and i wanna try to read/write the Stack of this Application with a Win32 App. (Is it possible???)

I write myself a small pure DOS (no extender) Application to point out how NTVDM.EXE is handling the Stack. Then i Debugged the Application with ollydbg but i can't find out how the stack is access.

Then i wrote a Win32 app and try ReadProcessMemory to read the memory of the Process (my testapp interpreted by ntvdm.exe) and check if it changed.
I wanted obtain the Address of the stack but didn't work. Delivered only a dump of NTVDM.EXE

After that i tried the Debug API's to access the stack, and read out ESP with GetThreadContext and check that value it is (esp=248).
Then i read the pointer from [esp]. but it also fails

Any Suggestion to get this Probleme solved or more detailed information about NTVDM.EXE i read two post about ntvdm here with some good info.

DOS APP Teststack.exe -> teststack.asm
Win32 APP Debug4.exe -> debug.asm

you can take a look a my sources under h**p://phalcon.net/masm32/

sincerly

Nukacola

Have you tried WinDbg? It surely is better than OllyDbg for debugging applications running with NTVDM.

No but i will try that tomorrow

Thanks for that tip