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Catalogue of Arcade Emulation Software - the Absolute Reference

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X-Arcade

X-Arcade

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chinagat.c

0.37b16 [Paul Hampson]


TODO:

- No backgrounds ROMs from the original board... This may be related to the SubCPU. I don't think it's contributing much right now, but I could be wrong. And it would explain that vast expanse of bankswitch ROM on a slave CPU.... Just had a look at the sprites, and they seem like kosher sprites all the way up.... So it must be hidden in the sub-cpu somewhere? Got two bootleg sets with background gfx roms. Using those on the original games for now.

- Timers are too fast and/or too slow, and the whole thing's moving too fast

- Port 0x2800 on the Sub CPU: All those I/O looking ports on the main CPU (0x3exx and 0x3fxx). One's scroll control. Prolly other video control as well. Location 0x1a2ec in cgate51.bin (The main CPU's ROM) is 88. This is copied to videoram, and causes that minor visual discrepancy on the title screen. But the CPU tests that part of the ROM and passes it OK. Since it's just a simple summing of words, another word somewhere (or others in total) has lost 0x8000. Or the original game had this problem. (Not on the screenshot I got). The Japanese ones have a different title screen so I can't check.

- ADPCM in the bootlegs is not quite right.... Misusing the data? They're nibble-swapped versions of the original roms... There's an Intel i8748 CPU on the bootlegs (bootleg 1 lists D8749 but the microcode dump's the same). This in conjunction with the different ADPCM chip (msm5205) are used to 'fake' a M6295. Bootleg 1 ADPCM is now wired up, but still not working :-( Definantly sync problems between the i8049 and the m5205 which need further looking at.


NOTES:

- Driver based on Double Dragon source.