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I'm having a go at writing my own "toy" OS and for the moment I'm doing it mostly in assembly (NASM) - partly because I'm hoping it will help me understand x86 disassembly and also because I'm finding it fairly fun too! This is my first experience programming in assembly - I'm picking things up quicker than I expected, however as with learning any significantly different language I'm finding that my code is structured fairly chaotically as I try to figure out what patterns and conventions I should be using. At the moment in particular I'm struggling with: Keeping track of registers At the moment everything is in 16 bit mode and so I only have 6 general purpose registers to play with, with even fewer of those usable for accessing memory. I keep on trampling over my own registers which in turn means I'm frequently swapping registers around to avoid this - consequently I'm having a hard time keeping track of what registers contain what values, even with liberal commenting. Is this normal? Is there anything I can do to help make things easier to keep track of? For example I've started commenting all of my functions with a list of the registers that are clobbered: ; ================ ; c_lba_chs ; Converts logical block addressing to Cylinder / Head / Selector ; ax (input, clobbered) - LBA ; ch (output) - Track number (cylinder) ; cl (output) - Sector number ; dh (output) - Head number ; ================ Keeping track of the stack In a couple of cases I've started using the stack when I run out of registers, but this is making things so much worse - anything more complex than a simple push call pop sequence to preserve registers causes me to loose track completely, making it tricky to even tell if I've got the right number of items on the stack (particularly when error handling is involved - see below), let alone what order they are in

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