Talk:F-22 Interceptor (Sep 17, 1991 build): Difference between revisions
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(Created page with "This is fully identical to the final ROM. What's happening is that this game is doing something unusual for the Mega Drive: it only maps odd bytes above the 512KB mark — pre...") |
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This is fully identical to the final ROM. What's happening is that this game is doing something unusual for the Mega Drive: it only maps odd bytes above the 512KB mark — presumably by using an 8-bit 128KB ROM in that space, with open bus on the even bytes. When the commonly circulating final ROM was dumped, the bus was read as byte <tt>1A</tt>; in this ROM it's read as <tt>00</tt> instead. Converting those <tt>00</tt>s to <tt>1A</tt> will give you the final ROM. All region versions of the game are like this and the game is specially coded to take this into account. - [[User:Andlabs|andlabs]] ([[User talk:Andlabs|talk]]) 22:47, December 22, 2022 (EST) | This is fully identical to the final <tt>F-22 Interceptor - Advanced Tactical Fighter (USA, Europe) (September, 1991).md</tt> ROM. What's happening is that this game is doing something unusual for the Mega Drive: it only maps odd bytes above the 512KB mark — presumably by using an 8-bit 128KB ROM in that space, with open bus on the even bytes. When the commonly circulating final ROM was dumped, the bus was read as byte <tt>1A</tt>; in this ROM it's read as <tt>00</tt> instead. Converting those <tt>00</tt>s to <tt>1A</tt> will give you the final ROM. All region versions of the game are like this and the game is specially coded to take this into account. - [[User:Andlabs|andlabs]] ([[User talk:Andlabs|talk]]) 22:47, December 22, 2022 (EST) | ||
Revision as of 03:47, December 23, 2022
This is fully identical to the final F-22 Interceptor - Advanced Tactical Fighter (USA, Europe) (September, 1991).md ROM. What's happening is that this game is doing something unusual for the Mega Drive: it only maps odd bytes above the 512KB mark — presumably by using an 8-bit 128KB ROM in that space, with open bus on the even bytes. When the commonly circulating final ROM was dumped, the bus was read as byte 1A; in this ROM it's read as 00 instead. Converting those 00s to 1A will give you the final ROM. All region versions of the game are like this and the game is specially coded to take this into account. - andlabs (talk) 22:47, December 22, 2022 (EST)