Terminate and Stay Resident x86 ASM sample code for MS DOS
Code Roy Massaad
License : MIT
Date: circa 1997
Category: Archive/Nostalgia
This is old code for a Terminate and Stay Resident tiny program i did when i was a teenager.
It does nothing major, it loads in MS memory and stays there, intercepting keyboard key press interupts, replacing the '9' character with '6'. (never got the chance to use it to prank someone)
I did it to learn x86 assembly back then and to understand some of the behavriors of viruses such as TSR loading
It is commented, but keep in mind these are the comments of a 16 year old, so brace yourselves
It builds easily with microsoft MASM ver 6 (5 or older should work fine as well)
And it goes without saying this runs in DOS mode, not under Windows
I wanted to study also how to copy code into boot sectors for loading and infecting .exe and .com files and even polymorphism, but never went further than TSR
Enjoy