Hello,
For instance, if I have
mov ah,4ch
int 21h
How can you determine what int21h returns? I am writing a debugger in my spare time. So please experts do help me.
Thanks
Jack
by looking it up in the interrupt list or whatever documentation you have ?
Water flows down the stream
How to ask questions the smart way!
Not sure what the goal is here, but INT 21/4C seems like a bad example because it terminates a program, so it doesn't "return" anything.
Thank you all.
Basically, When I trace my code. I have a setState function that concurrently update the states of the registers/memory. But when I run into a DOS interrupt instruction, I am stuck as I can't predict the results of the instruction. For instance
mov ax, 10
mov ch, 3
I could setState(AX, 10);
and setState(CH,3);
Thanks
Jack
But when I run into a DOS interrupt instruction, I am stuck as I can't predict the results of the instruction.
Right, and you can't predict them otherwise you'd have a full bios/dos/etc. emulator instead of a debugger.
May I know how DOSBOX handles it?
Thanks
Jack
It emulates those that are needed.
Could you recommend a open source full-fledged dos-based debugger for me? I want to make modification to it to suit my needs...
Many thanks
The open watcom debugger, wd, is maybe more powerful and complex than you're looking for, though.
Are these "needs" you mention a call stack?
