/vr/ - Retro Games

6502 ASM.
Can anyone explains to me what EOR and ORA do in terms I'm likely to understand? I've been googling for it but all I find are explanations on what the terms "mean" and the different addressing modes for them.
Anyone knows of a good "6502 ASM for retards" guide?

I finally understood the cause of a glitch that's been bothering me since I made the shield for Protoman.

What I did is take the player's X-Y coordinates low, add a sum to it to create a "zone" and check if the projectiles are in that zone.

The issue being that, if the player's original X coordinate is equal or more ot F1 (which can happen in the middle of the screen during scrolls), and that I add +0F, it will go over and back to 00+ and therefore break my system.

I'd like to understand how the game originally works around this issue, I believe it uses the X-Y coordinate high which represent room number, but I don't understand the relation they're making.
Pic related. ram addresses 330 and 378 are X and Y coordinate low respectively, and 348 and 390 are X and Y coordinate high (room numbers).

Thanks