Brings back fond memories. Used to use the "debug" program that came with DOS to play with assembly as a student, because TASM (Borland) and MASM (Microsoft) cost money, but doing that gave one a real feel for assembly. Coding a short JMP instruction, for example, requires a relative address from the current instruction PC, so you had to hand compute that and code it in. And if you added instructions between the JMP and the target, then you had to go back and change it.
