Re: [Freedos-devel] jemmex crash dumps and game compatibility in a 3/2024 youtube about SBEMU

[<je...@sh...>]

Hi Eric,

I was having similar issues. So, switched to VSBHDA. Afterwards, I was still experiencing lots of problems and submitted a bug report. But as it turned out, it was user error. I just needed to change the configuration settings and that fixed me right up. 

:-) 

> On Aug 15, 2024, at 6:13 PM, Eric Auer via Freedos-devel <fre...@li...> wrote:
> 
> 
> Hi! I have been watching
> 
> https://www.youtube.com/watch?v=K6-AlpCEqpc
> 
> where Phils Computer Lab tests SBEMU with the pre-installed
> FreeDOS image which you can download from SBEMU's crazii.
> 
> At one point, a game crashes with a loop of the following,
> some leading 0s omitted by me:
> 
> JemmEx: exception 06 occured at CS:EIP=9689:FF14, ERRC=0
> SS:ESP=D70A:C7D4 EBP=FFFF EFL=33093 CR0=80000013 CR4=200
> EAX=FFFF9002 EBX=FFFF0007 ECX=FFFFFF00 EDX=FFFFF1EC
> ESI=40001A EDI=0EFF
> DS=0040 ES=FFFF FS=FFFF GS=00D9 [CS:IP]=FF FF FF FF FF FF FF FF
> Press ESC to abort program
> 
> JemmEx: exception 06 occured at CS:EIP=9689:FF14, ERRC=0
> SS:ESP=D70A:C7BE EBP=FFFF EFL=33093 CR0=80000013 CR4=200
> EAX=FFFF9002 EBX=FFFF0007 ECX=FFFFFF00 EDX=FFFFF1EC
> ESI=40001A EDI=0EFF
> DS=0040 ES=FFFF FS=FFFF GS=00D9 [CS:IP]=FF FF FF FF FF FF FF FF
> Press ESC to abort program
> 
> and so on, all registers except ESP stay constant and the
> video shows a loop of JemmEx messages scrolling through as
> the stack pointer goes down while CS:EIP is frozen pointing
> to an impossible FF FF opcode. Exc. 06 is undefined opcode.
> 
> As the messages scroll so fast, I am not sure whether each
> instance actually shows all lines. The may even be nested?
> 
> Later in the same video, F-117A mgraphic crashes, with far
> more readable JemmEx reactions:
> 
>> JemmEx: exception 0C occured at CS:EIP=0360:2A01, ERRC=0
>> SS:ESP=0360:FFEA EBP=0 EFL=33202 CRO=80000013 CR4=00000200
>> EAX=0021 EBX=0 ECX=0 EDX=FFEC ESI=FFFF EDI=01FF
>> DS=0350 ES=0350 FS=0350 GS=O2BA [C3:IP]=36 8B 28 36 8B 88 B8 01
>> Press ESC to abort progran
>> JemmEx: exception 06 occured at CS:EIP=0000:0108,   ERRC=0
>> SS:ESP=0914:10002 EBP=C600 EFL=00033246 CRO=80000013 CR4=200
>> EAX=0 EBX=0 ECX=0 EDX=0 ES1=0 EDI=0
>> DS=0 ES=0 FS=0 GS=0 [C3:IP]=65 F0 00 F0 36 03 00 C0
>> Press ESC to abort program
>> JemmEx: exception 0D occured at CS:EIP=D79B:0984, ERRC=0
>> SS:ESP=00D9:08D0 EBP=0 EFL=33093 CRO=80000013 CR4=200
>> EAX=00FF EBX=0 ECX=FF54 EDX=0904 ESI=A8B1 EDI=0
>> DS=00D9 ES=D7A0 FS=0 GS=0 [CS:IP]=67 66 2E 83 3C 9D 4C 04
> ...
> 
> This starts with a stack error first, "mov bp,[ss:bx+si]"
> wrapping the end of the first 64 kB of the stack segment,
> then an undefined opcode exception apparently caused by an
> invalid locked combination saying GS: LOCK: ADD AL,DH etc.
> and finally a general protection fault.
> 
> Of course this does not tell much about whether it was
> futile to try to abort the program after the first stack
> exception, but note how there is no LOOP of exceptions
> here, so it gets a lot easier to read the messages :-)
> 
> Thanks to https://www.sandpile.org/ for their tables :-)
> 
> Likewise, the F-19 game also crashes, even with loadfix:
> 
> JemmEx: exception 0D occured at CS:EIP=1025:4142, ERRC=0
> SS:ESP:2025:DAC6 EBP=DAD0 EFL=33282 CR0=80000013 CR4=200
> EAX=0 EBX=FFFE ECX=9BCC EDX=4605 ESI=C88C EDI=0
> DS=2025 ES=46E8 FS=1015 GS=02BA [CS:IP]=89 47 01 89 7F 03 83 C6
> 
> which is mov [bx+1],ax and again wraps the end of some
> 64 kB boundary, but you actually get to read the text
> without a loop :-)
> 
> *So now I wonder why JemmEx exception messages sometimes*
> *end up in a loop, while usually they do not, luckily.*
> 
> The video features kernel 2043 (2021-05-14) FAT32 Watcom 386,
> JemmEx 5.84 02/11/23, QPIEMU, FreeCOM 0.85a 2021-07-10,
> UDVD2 (not used, no drive in the shown thin client),
> SBEMU (in VIA VT82XX AC97 mode), CuteMouse 2.1beta4,
> originally based on the FreeDOS 1.3 distro, it seems.
> 
> It also mentions Aladdin failing to start, with the
> message "XMS allocation error.." (sic!) and Lotus 3
> crashing with "Interrupt divide by zero, stack:
> D34C 0360 3002 518D ADE8 EB6F EB4A 314A
> E8D2 B117 C689 C389 7C80"
> 
> In Sam+Max, audio setup fails with "hdpmi: fatal exit 0007".
> In Space Quest 5 adlib works, while emulated SB use hangs.
> 
> Finally, some related GOOD news from this
> video: TETRIS CLASSIC is working fine :-)
> 
> It is one of the games mentioned in my
> "game compatibility updates?" post as a
> game which was NOT working in 2022 :-)
> 
> Cheers, Eric
> 
> 
> 
> _______________________________________________
> Freedos-devel mailing list
> Fre...@li...
> https://lists.sourceforge.net/lists/listinfo/freedos-devel