{Modifizierte ROMs} Ich habe Tim von Arcadecollecting mal direkt angefragt, weil mich die technischen Details der modifizierten ROMs interessiert haben. Er hat mir freundlicherweise das Spiegeln der Modifizierten ROMs erlaubt und mir auch ein paar interessante Infos geliefert:

Dear Tim, May I ask you for your kind permission to mirror your decrypted ROM-sets (Pang, Super Pang) on my site? One technical question: what was the reason for using /M1 as address line? If I understand it right, /M1 is provided by the Z80 at opcode fetch, so I assume, you placed all opcode data in the upper half of the EPROMs, and all data in the lower half. Was it too complex to decrypt data without opcodes and to keep it combined in the original half sized EPROMs?

Hi Wolfgang, You're welcome. Yes, it's okay if you host the ROMs on your site. I appreciate having a link back to my site. The reason for using /M1 is because that is the fastest and most accurate way to tell the difference between an opcode and data. A simple disassembly won't give 100% accurate results because any disassembler doesn't know which is which either (since it's not executing). A disassembler just blindly treats the first byte (or two) as an opcode and therefore the next must be data. Wrong! ;) It's possible to get close to 100% by executing the code and keeping track of what addresses have been executed to see which is which, but getting 100% that way is very hard too because there will be some parts of the ROM that never get executed. The only game I ever was able to get 100% with was Crazy Climber and it was a combination of luck in the way they stored data as well as a lot of analyzing the code as it ran. Regards, Tim

Modifiziertes ROM Pang Decrypted
Modifiziertes ROM Super Pang Decrypted

Bei einer Conversion von Pang zu Super Pang ist natürlich auch darauf zu achten, dass die GFX-ROMs die Richtigen sind! (die sind nicht in den ZIPs enthalten.)