Excellente idée !
Voici la réponse de SyX (qu'il m'autorise à copier coller ici ).
Citer :
Well, you can use the UK one from Kevin, because there is only 4 differences between french rom and uk (the same ones between uk and the spanish one), those are:
1.- The keyboard table: The chars are associated to the key combinations (without or with SHIFT or CONTROL pressed).
2.- The font: A few chars are changed for having a more french experience
3.- In the initialization text appears f3 for french, instead of v3 for uk or s3 for spanish. Some games read from the rom this byte for trying to detect if we are in a spanish, french or uk cpc... thai does not do this
4.- There is a place not used in the firmware ROM, that goes from $058A - $0590, that is filled with $C7, except the byte in $058A that is $26 in UK rom, $44 in french rom and $B3 in the spanish rom. As i have based my FW3.1x in the UK rom (and change the keys and fonts when i'm building these roms), here is $26. I imagine it was used as 7 bytes of padding in the routine that finish in $0589, in case they need to change anything in it and use extra bytes, those free places are very rare in the firmware rom and they are used in patched firmware versions for new functions. Why am i wasting time explaining this "random" zone? Well, can you imagine what is doing the shit of Thai Boxing? xDDDD
Yes, exactly, it's using that zone in the rom xDDDD
Put a breakpoint in $8267, then load Thai Boxing and your emulator will stop in:
They are basically increasing HL, to discover where is the first $44 ("D") in the ROM, that is usually in $0653, instead of doing "LD HL,$0653", the "genious" making this code did that and i can promise this trick can not fool any "cracker" xDDD
This game only runs in uk, spanish or fw3.x by luck and doesn't run in french 6128s by bad luck xDDD
Copy the french rom to other file, open in an hex editor, change the $44 byte in $058A to any other value and you will be able to run Thai Shit perfectly with this new french rom
Other solution is fixing the game loader, or cracking the game or in the original floppy you will need to understand the encryptation algorithm (another boring R register decryption loop) and replace that loop for the "LD HL,$0653" and that is all.
1.- The keyboard table: The chars are associated to the key combinations (without or with SHIFT or CONTROL pressed).
2.- The font: A few chars are changed for having a more french experience
3.- In the initialization text appears f3 for french, instead of v3 for uk or s3 for spanish. Some games read from the rom this byte for trying to detect if we are in a spanish, french or uk cpc... thai does not do this
4.- There is a place not used in the firmware ROM, that goes from $058A - $0590, that is filled with $C7, except the byte in $058A that is $26 in UK rom, $44 in french rom and $B3 in the spanish rom. As i have based my FW3.1x in the UK rom (and change the keys and fonts when i'm building these roms), here is $26. I imagine it was used as 7 bytes of padding in the routine that finish in $0589, in case they need to change anything in it and use extra bytes, those free places are very rare in the firmware rom and they are used in patched firmware versions for new functions. Why am i wasting time explaining this "random" zone? Well, can you imagine what is doing the shit of Thai Boxing? xDDDD
Yes, exactly, it's using that zone in the rom xDDDD
Put a breakpoint in $8267, then load Thai Boxing and your emulator will stop in:
Code :
LD A,$44 <-- Suspicious value xDDD
.loop
CP (HL) <--- Ups, Firmware ROM is enabled and HL is pointing to it, this is not going to finish well xDDD
JR Z,.here
INC HL
JR .loop
.here
.loop
CP (HL) <--- Ups, Firmware ROM is enabled and HL is pointing to it, this is not going to finish well xDDD
JR Z,.here
INC HL
JR .loop
.here
They are basically increasing HL, to discover where is the first $44 ("D") in the ROM, that is usually in $0653, instead of doing "LD HL,$0653", the "genious" making this code did that and i can promise this trick can not fool any "cracker" xDDD
This game only runs in uk, spanish or fw3.x by luck and doesn't run in french 6128s by bad luck xDDD
Copy the french rom to other file, open in an hex editor, change the $44 byte in $058A to any other value and you will be able to run Thai Shit perfectly with this new french rom
Other solution is fixing the game loader, or cracking the game or in the original floppy you will need to understand the encryptation algorithm (another boring R register decryption loop) and replace that loop for the "LD HL,$0653" and that is all.
Pour ceux qui parlent anglais, nul n'est besoin de commentaire.
En gros, il s'agit d'une routine qui va chercher la première occurrence de $44 dans la ROM. Pas de bol, en ROM FR, on n'a pas la meme adresse que dans les ROM SP et UK, et donc, on échoue.
Donc, le comportement est normal. Mieux, le comportement est exactement celui attendu.
Nous avons donc le fin mot de l'histoire (Mercu a SyX pour l'explication, et à TotO pour m'avoir soufflé son nom !)
)