Xeda how did you learn the hex codes? I think that I might try to do that depending on how long it would take to learn the basics of it.
It is the same than learning ASM just that you replace the commands by their hex equivalents (like "ret"==C9 or "xor a"==AF)
Yes, that is correct
However, the advantage to learning the hex is that it helps you optimise and understand how the z80 works (also, it makes self modifying code a breeze). I mentioned the tutorial that I started and have yet to complete. I attached it to this post, so hopefully that can help. Really, it is a lot easier than it might sound because the opcodes have lots of patterns in them. For example:
jr nz,* == 20**
jr z,* == 28**
jr nc,* == 30**
jr c,* == 38**
You will probably need a chart, too, to get convert between hex and mnemonics. I also attached the one I made which also includes a quick breakdown of what each type of instruction does. Also, if it works for your spreadsheet viewer thing, I attached some sticky notes to a bunch of the cells to give more specific info if you hover the mouse over it (I don't think it works for all file types).