English Amiga Board - View Single Post - WinUAE

tlenl · 27 December 2018, 19:12

Ok, after having done a quick realtime view of memory around 0224, near parts of cells memory are moving and changing constantly so the method of a fixed fingerprint calculation is not appliable (search for memory blocks that after hash results in fingerprint).
Restricting the area of fingerprinting we would have much higher probability of hash collision (same hash for different memory blocks).

A solution could to be find a fixed string (or graphic memory block) that appears at the beginning (or near beginning in the middle) of the game (using the hash method), that has ALWAYS the same distance (regardless the game version) from the address to patch, and use that address as the base address to add (or subtract) an OFFSET to find the right address to patch.

Not an impossible task but need the analisys of many versions of the game.

Thank you, i'll try Wings as soon as (what a game!).

27 December 2018, 19:12	#13
tlenl Registered User Join Date: Dec 2018 Location: Italy Posts: 19	Ok, after having done a quick realtime view of memory around 0224, near parts of cells memory are moving and changing constantly so the method of a fixed fingerprint calculation is not appliable (search for memory blocks that after hash results in fingerprint). Restricting the area of fingerprinting we would have much higher probability of hash collision (same hash for different memory blocks). A solution could to be find a fixed string (or graphic memory block) that appears at the beginning (or near beginning in the middle) of the game (using the hash method), that has ALWAYS the same distance (regardless the game version) from the address to patch, and use that address as the base address to add (or subtract) an OFFSET to find the right address to patch. Not an impossible task but need the analisys of many versions of the game. Thank you, i'll try Wings as soon as (what a game!). Last edited by tlenl; 27 December 2018 at 19:29.