I mostly work with the GB(C) using bgb and wla-dx. wla-dx allows me to put my code on top of a base ROM, so it takes care of the code injection for me.
I couldn't imagine doing a large-scale ASM hacking project without an assembler. Memorizing the opcodes would be tedious, but that's not the main problem... the assembler is simply much more flexible. I can move code around, define labels, insert comments, easily. This is all stuff I consider necessary for big assembly hacks.
I feel the same way. The flexibility of an assembler is a must. Changing even a one or two instructions, or such, can change source code and code alignment. I can't imaging doing that by hand, unless the replacement code was nothing more than a few bytes.
I hack completely via a hex editor. I like to be able to view everything with the Code Data Logger within FCEUX.
Everyone has they're own method of writing 6502. I happened to learn mostly from kuja killer, and that was how he wrote/modified 6502 asm.
I can look at hex values and know just about all of the opcodes for them from memory.
I've gotten so much flack from people saying I don't know how to do asm if I do it via a hex editor. It doesn't matter how you write it or what method you use, as long as it works.
I'm sure if I learned from someone else, and they actualy 'wrote' it out, then probably today that would be the way I write asm.
Well, that's not ASM or Assembly. That's "machine language". I mean, if you're writing code directly in a hex editor. Assembly has a syntax, even if it's nothing more than bare bones mnemonics (although almost all assemblers have a higher level functionality to them as well). There's nothing wrong with that though, if you're completely comfortable with that approach.
Being an assembly programmer and being an assembly hacker, aren't mutually exclusive. Being one, doesn't equate to being the other. Well, IMO. Don't get me wrong, I'm not here to criticize anybody. Hackers (that hack code) are a strange and special lot. The patience and time it takes to unravel someone else's code and understand it; not every programmer is cut out for that kind of stuff. And so I was curious, how many people moved onto using an assembler for their replacement code in hacks. Of course, I'm assuming most here don't have a background in assembly programming.
Anyway, for asm hacking - I always include the base rom or binary (extracted from CD) into the assembler and simply assemble new code directly over it. Same with data. Here's just one small file, of many, for my Megaman hack: http://pastebin.com/3uXBMrAW