Today

Today after summarising my last year in the UK, I'm going to do a bit of ARM Assembly.

Nowadays my interests are in the exception vectors of the ARM processor. I am experimenting things to see it work in action. Yesterday late at work I discovered that software interrupt instructions are intercepted by the debugger if you tell it to do so (well, something not very unusual). So basically you can't see what the "real" SWI is, because all you see is a usual jump to the next instruction. Now I'm gonna change that, write a program in gnu as, that sets up stacks for all exception modes, and installs various handlers - stuff that early dos viruses did. Now, there's a linking problem here as well, you have to link each handler into a specific address, such that when the loader loads your elf image, it automatically copies the handlers to their desired addresses, and your usual main() code that sets up stacks, to a default usual program address. So this will also initiate my first tweaking with the linker. Also I'll go deeper in experimenting with readelf and objdump to see if my linking worked correctly.