In my emulator, the title screen has a green-ish color instead of black, and the game hangs after pressing START because of a RAM clearing routine, but always calling the JMP address from RAM $07F4.
Any clues? A CPU bug?
(after 2 milions and half lines of debugging code)
Code:
6C, F9F7 JMP ($07F4)
48, CA01 PHA
A9, CA02 LDA #$00
8D, CA04 STA $E002
8D, CA07 STA $E003
68, CA0A PLA
40, CA0B RTI
D0, E962 BNE $E94D [A:0 X:F4 Y:10 S:F9 P:A0]
95, E94D STA $00, X [X=F4, Addr+X=F4]
9D, E94F STA $0200, X [X=F4, Addr+X=2F4]
9D, E952 STA $0300, X [X=F4, Addr+X=3F4]
9D, E955 STA $0400, X [X=F4, Addr+X=4F4]
9D, E958 STA $0500, X [X=F4, Addr+X=5F4]
9D, E95B STA $0600, X [X=F4, Addr+X=6F4]
9D, E95E STA $0700, X [X=F4, Addr+X=7F4]
E8, E961 INX
D0, E962 BNE $E94D [A:0 X:F5 Y:10 S:F9 P:A0]
95, E94D STA $00, X [X=F5, Addr+X=F5]
9D, E94F STA $0200, X [X=F5, Addr+X=2F5]
9D, E952 STA $0300, X [X=F5, Addr+X=3F5]
9D, E955 STA $0400, X [X=F5, Addr+X=4F5]
9D, E958 STA $0500, X [X=F5, Addr+X=5F5]
9D, E95B STA $0600, X [X=F5, Addr+X=6F5]
9D, E95E STA $0700, X [X=F5, Addr+X=7F5]
E8, E961 INX
6C, F9F7 JMP ($07F4)
00, 0000 BRK
48, CA01 PHA
A9, CA02 LDA #$00
8D, CA04 STA $E002
8D, CA07 STA $E003
68, CA0A PLA
40, CA0B RTI
D0, E962 BNE $E94D [A:0 X:F4 Y:10 S:F9 P:A0]
95, E94D STA $00, X [X=F4, Addr+X=F4]
9D, E94F STA $0200, X [X=F4, Addr+X=2F4]
9D, E952 STA $0300, X [X=F4, Addr+X=3F4]
9D, E955 STA $0400, X [X=F4, Addr+X=4F4]
9D, E958 STA $0500, X [X=F4, Addr+X=5F4]
9D, E95B STA $0600, X [X=F4, Addr+X=6F4]
9D, E95E STA $0700, X [X=F4, Addr+X=7F4]
E8, E961 INX
D0, E962 BNE $E94D [A:0 X:F5 Y:10 S:F9 P:A0]
95, E94D STA $00, X [X=F5, Addr+X=F5]
9D, E94F STA $0200, X [X=F5, Addr+X=2F5]
9D, E952 STA $0300, X [X=F5, Addr+X=3F5]
9D, E955 STA $0400, X [X=F5, Addr+X=4F5]
9D, E958 STA $0500, X [X=F5, Addr+X=5F5]
9D, E95B STA $0600, X [X=F5, Addr+X=6F5]
9D, E95E STA $0700, X [X=F5, Addr+X=7F5]
E8, E961 INX
6C, F9F7 JMP ($07F4)
00, 0000 BRK
Any clues? A CPU bug?
(after 2 milions and half lines of debugging code)