[M2] [ASM] Good GB ASM tutorials?

[RT-55J]

Alternate title: I got a breakpoint to work like I wanted. Now what?

Long story short: I decided to do some hardcore debugging to find out how some data I found in Metroid 2 should be interpreted. After a bit of searching, I found that BGB did a pretty bang-up job (no$gb couldn't do on-access breakpoints, from my cursory examination). Anyhow, after a bit of messing around, I was able to set a breakpoint in the level data that would trigger upon hitting the first screen transition and nowhere else (pic), and from there I figured that I could step through the instructions and figure out what's going on. But's it's all Greek to me.

As far as I can tell, the code at that point loads the value from 0x4300 + an arbitrary offset, does a couple bitwise things, and then loads some stuff from an array (?) in WRAM. The problem here is that I don't actually understand what's going on down at the logic-level, so I feel like I'm just guessing what each opcode does. So, in addition to a no-nonsense tutorial on the subject, I feel like a "plain English" description of what each line is doing would help me understand what's going on better ("...and then it loads the value from 0x1234 into the A register" counts as plain English to me). What I'd like to eventually be able to figure out is (a) where the array in WRAM is pulled from/generated and (b) how is this all interpreted.

(Here's the documentation I'm currently using: GB memory map (helpful), opcode list (obtuse (duh)).)

[Quote58]

Looks quite similar to SNES asm, so I may take a look at some point (m2 is a favourite of mine, so I'd love to see some progress made with hacking it)

[Antidote]

Find some Z80 tutorials, since the GB is largely based on the Z80 processor, bare in mind that the CPU is NOT a Z80 but a highly customized CPU that is Z80-like.

[P.JBoy]

If you ever come onto the metconst IRC, I'd be happy to give you a hand with this sorta thing