ASM hacking and debugger

So I was about to write some ASM stuff, turns out the No$GBA doesn’t do it for my ROM, it says unknow opcode here and there (maybe due to some patches of FEBuilder which changed some ot the code segment? idk).
Anyways, are there any good debuggers for GBA other than that which would work?

And also, is the location of RAM data consistent between an edited and vanilla FE8 ROM (the values being at the same offset)? If so, I would just use vanilla FE8 for writing some simple stuff like comparing unit values etc. etc,

I’m very proficient with ASM in general but sadly I got no clue on GBA specific stuff.

mGBA has a memory viewer, IIRC. You could try that.

You’ve probably been playtesting on an inaccurate emulator such as VBA-M. Use mgba (with settings edited to crash when hardware would) for general use and no$gba for debugging asm. If it’s saying undefined opcode / crashing, it means it would be crashing on real hardware too.

Ram to use can be repointed. For example, in skill sys fe8u the save data has been rearranged using EMS, so save files between vanilla and skill sys aren’t compatible.

I highly recommend setting up a buildfile for the purposes of quickly testing custom code. You can insert it to an febuilder project once you’ve bugtested it.

Easy setup

Advanced setup (make)

Maybe it is because that no cash gba uses x86 language to emulate the gba bios to avoid being illegal. However, you can try to use the original bios of GBA. No cash gba supports that. Search and download the original bios file. Rename it as “biosgba.rom”, and put it into the root path of no cash gba will do.
I can’t guarantee that it will work, but maybe it is worth a try… :thinking:

Please forgive my poor English. I’m not native in it. :slightly_smiling_face:

As for other debuggers, I personally know arm-none-eabi-gdb as a source code level debugger, but it supports a few instructions that can be used to debug binary roms.
However, gdb doesn’t have a GUI :frowning_face:

If you are interested in it, maybe you can search for its manual and get more information. :wink:

If you wish to use it, you can install devkitPRO. It contains the tool.

Thanks everyone!
Tthat’s quaite a lot of input, gotta look into the stuff

Oh, here is another thing. After you do this, you’ll need to press F11 on the debug screen of NO$GBA. Click ‘Others’ tag, and set ‘emulate gba bios by real gba.rom’.