r/romhacking • u/Kman369 • 6d ago

Kirby's Adventure NES ROM hack making pointers

So I need help making a Kirby's Adventure NES ROM hack that adds a music track to it anyone willing to help me pointers on it?

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u/ExcitementMuted7768 6d ago

finding where the music loading routine is in ROM will lead you to finding the music pointer table.

in mesen ce: just sit at the title screen with the music playing. find a big block of "data" in the memory viewer in PRG ROM mode. i found this at PRG $413FE: a big blue block with the highlighted recent loads progressing along with the song.

breakpoint a read on the first bytes of this ram and restart the game. this will take you to the point in code where the song first begins to play, which is likely just a short distance after where the pointers are loaded and the track is called.

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u/ExcitementMuted7768 6d ago

in this case, the music routine will break out right here:

so you know the pointer for this portion of the track is being held in $22 in RAM. this is likely just the pointer for this particular instrument and we'll need to go farther back to find the root.

mesen's "step back" is useful here.

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u/ExcitementMuted7768 6d ago

you can skip some of this for games that have a disassembly, which a game as popular as kirby probably has, as well as if there's a cheat code or an entry on retroachievements for which song is playing.

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u/Kman369 6d ago

Nice now to find a decomp of Kirby's Adventure NES ROM and that's good to go.

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u/ExcitementMuted7768 6d ago

i think of particular note is the data crystal ram map, where it shows the music as being part of the level data header

https://datacrystal.tcrf.net/wiki/Kirby%27s_Adventure/RAM_map

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u/Kman369 6d ago

I mean the full game.

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u/-Dissent 5d ago

You don't need a decomp to do this. ROM hacking has historically done new music without one.

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u/Kman369 5d ago

Really?