Looking for a simple spreadheet-like program for developing ROM patches

[rimsky82]

Adding code would do so. Replacing code would not.

[BeyondTheStatic]

This was for a trainer I did some 2 years ago for Double Dragon 2. It is for mapper 4. The best way to bank switch is to locate any calls to the bank switch routine and jump to a different location execute your own routines and then execute the original one.

Hmm, I'll give this a more thorough examination when I have the time. But I need to know, how do you locate those calls? And how were you able to alter addresses below $8000? I'm just one cheat away from finishing my sharpshooter patch for Zelda 1 (which has been on hold for months now), but the code I need to alter is below $8000, and I can't edit those hex values in FCEUX. Do I need to pick up one of the hex editors from romhacking.net?

[BeyondTheStatic]

Adding code would do so. Replacing code would not.

Oh, then I'm clear

[rimsky82]

And how were you able to alter addresses below $8000?

When Zelda starts, it copies some of the asm from rom into RAM. Put a write breakpoint on one of those addresses below $8000 and reset the game. You'll find where the code is coming from in the ROM.

[BeyondTheStatic]

When Zelda starts, it copies some of the asm from rom into RAM. Put a write breakpoint on one of those addresses below $8000 and reset the game. You'll find where the code is coming from in the ROM.

I'll give it a go. Thanks, rimsky