RE: POSE and find crash

krollin Sat, 29 Jan 2000 01:16:50 -0800


Thanks, that helps a little more.

Disassembling the opcode you provided, it turns out to be "JSR xxx(A5)", where
JSR means "jump to subroutine" and "xxx" is an offset that appears in memory
after the opcode. It actually doesn't matter what the offset is. The relevent
information is that you're accessing A5, apparently in an attempt to jump to
code in a different segment.

Using Poser 3.0a3 would help in detecting this problem. It does a quick check of
the program counter on JSR (and other) opcodes.  With that check, instead of
crashing, you would have received an error message from Poser along the lines of
"%Application %version is attempting to change the emulated program counter to
%address.  This address is invalid because %reason". At that point you could
have dropped into a debugger, gotten a stack trace, and found the inter-segment
call.

-- Keith Rollin
-- Palm OS Emulator engineer






"Chris Yourch" <[EMAIL PROTECTED]> on 01/28/2000 06:31:03 PM

Please respond to "Palm Developer Forum" <[EMAIL PROTECTED]>

Sent by:  "Chris Yourch" <[EMAIL PROTECTED]>


To:   "Palm Developer Forum" <[EMAIL PROTECTED]>
cc:    (Keith Rollin/HQ/3Com)
Subject:  RE: POSE and find crash





Hi,

I am running version 2.1d29 of the emulator under Windows NT workstation
4.0 SP6. I am using codewarrior 4.0.1 build 0436.

To cause the crash I run the global Find when my application is not active.
When my PilotMain gets called with the find request I call "new" to
allocate an instance of a database table. Before the new returns I get a
Windows application error msgbox which says "The instruction at
"0x0044c21c" referenced memory at "0x8001adda". The memory could not be
read.".

Here is the call stack, starting at the top with the values of the
variables:

do_get_mem_word(void* a)      a == 0x8001adda           (machdep_memory.h,
line 75)
get_iword (uae_s32 o)         o == 0                    (newcpu.h, line
142)
Emulator::Execute()      opcode == 20141           (CPU_REG.cpp, line 801)
CPU::run_undetached()         breakReason == 128        (CPU_MT.cpp, line
537)
omni_thread_wrapper(void* ptr)     return_value ==      0xc0502938
(nt.cpp, line 491)

I hope this is enough information.

Thanks,
Chris



   -----Original Message-----
   From:   [EMAIL PROTECTED]@RIAG
   Sent:   Friday, January 28, 2000 4:12 PM
   To:     "Palm Developer Forum" <[EMAIL PROTECTED]>
   Subject:  Re: POSE and find crash



   Chris,

   Can you clue us in on what version of Poser you're using? What platform
   you're
   running it on? What the value of "a" ? What you're doing to cause the
   problem/crash?  I greatly laud and appreciate your efforts to track down
   the
   problem to the particular line that's crashing, but without a bigger
   context,
   there's not much anyone can do about it. All you're telling us is that
   something
   is passing do_get_mem_word an invalid pointer.

   -- Keith Rollin
   -- Palm OS Emulator engineer






   "Chris Yourch" <[EMAIL PROTECTED]> on 01/28/2000 07:17:53 AM

   Please respond to "Palm Developer Forum" <[EMAIL PROTECTED]>

   Sent by:  "Chris Yourch" <[EMAIL PROTECTED]>


   To:   "Palm Developer Forum" <[EMAIL PROTECTED]>
   cc:    (Keith Rollin/HQ/3Com)
   Subject:  POSE and find crash





      Hi,

      I crash the emulator (access violation) when my app is not the one
      running. I have checked the usual culprits, i.e. no globals or
   statics
      are being used and I am not overwriting any memory. Also, no virtual
      functions are being called and finally, I have plenty of stack space.

      What I am doing is making a call to new and then it crashes the
      emulator.

      I compiled a debug version of the emulator, ran a find again and it
      crashed in the following location:

      module:      machdep_memory.h
      function:    do_get_mem_word()
      line:   75

      Does this mean anything to anyone familiar with the emulator?

      Thanks,
      Chris

      P.S. Here is the code for the function:

      static __inline__ uae_u16 do_get_mem_word(void* a)
      {
         return *(uae_u16*) a;
      }



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RE: POSE and find crash

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