Mail Archives: djgpp/2000/04/20/18:17:32
Eli Zaretskii wrote:
>
> > OB_Check was called by check_object, which is a bridge between the VM and
> > my functions in the 'real world'.
> >
> > check_object was called by callfunc, which is used by SEER to call
> > 'real world' functions outside of VM-space
> >
> > All of which which suggests that the crash is happening inside the SEER
> > library.
>
> The crash is indeed in a function called by SEER, but the important
> question is: who is responsible for putting garbage on the object that
> triggers this print-out?
A common factor of the problem seems to be that it happens inside the VM,
I have not yet had in incident outside of the VM-space,
It seems that real-world functions which have an Object as their first
parameter sometimes get a garbled pointer when called from VM-space.
I recompiled SEER to use the portable method of calling real-world
functions instead of the Intel-specific method and it hasn't had this problem
since.
>
> > eax=00000001 ebx=00000000 ecx=00000073 edx=beefdead esi=ffffffff edi=00252d7c
> > ebp=00251d08 esp=00250910 program=C:\IRE\IRE.EXE
>
> You edited out the first two lines of the crash message. What were
> they saying?
I don't know. I run in 25 line mode and they went out the top of the screen.
>
> > cs: sel=00a7 base=10000000 limit=010cffff
> > ds: sel=00af base=10000000 limit=010cffff
> > es: sel=00af base=10000000 limit=010cffff
> > fs: sel=00c7 invalid
> > gs: sel=00bf base=00000000 limit=0010ffff
> > ss: sel=00af base=10000000 limit=010cffff
>
> Wow! The FS selector is invalid! Do you have any idea why? Does
> SEER use the FS register? If so, you want to check your code to make
> sure you don't use FS in a way that interferes with SEER's usage.
I don't change the FS register in any of my code. SEER might but I
haven't checked. Interestingly, if CTRL-BRK is pressed during startup,
FS is sometimes flagged as invalid then as well.
--
JP Morris - aka DOUG the Eagle (Dragon) -=UDIC=- DOUG-15 AT bigfoot DOT com
Fun things to do with the Ultima games (http://ithe.cjb.net)
Developing a U6/U7 clone (http://fly.to/ire)
d+++ e+ N+ T++ Om U1234!56!7'!S'!8!9!KA u++ uC+++ uF+++ uG---- uLB----
uA--- nC+ nR---- nH+++ nP++ nI nPT nS nT wM- wC- y a(YEAR - 1976)
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