From:	frazer AT rtp DOT ericsson DOT se (Scott Frazer)
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: emacs 19.34 crashes immediately on win nt 4.0
Date:	Wed, 26 Feb 1997 17:56:52 GMT
Organization:	Ericsson Data Services Americas
Message-ID:	<33147476.5759936@cnn.exu.ericsson.se>
References:	<Pine DOT SUN DOT 3 DOT 91 DOT 970218121808 DOT 20000I-100000 AT is>
NNTP-Posting-Host:	pc093.rtp.ericsson.se
Lines:	122
To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

Eli Zaretskii <eliz AT is DOT elta DOT co DOT il> wrote:

>I would still like to know whether a small test program that allocates and
>deallocates DOS memory crashes on NT (it might be something specific to
>Emacs). 

Eli/Charles,

Hi, I'm back trying to help fix the emacs crashing under WinNT 
v4.0 problem.

1)  I tried Charles' suggestion about getting rid of the 
ax = 0x3800 call.  I assume he meant this:

  /* Obtain the country code by calling Dos via Dpmi.  Don't rely on
GO32.  */
  info.size = (sizeof(dos_country_info) + 15) / 16;
  if (_go32_dpmi_allocate_dos_memory (&info))
    dos_country_code = 1;
  else
    {
      /*
      dpmiregs.x.ax = 0x3800;
      dpmiregs.x.ds = info.rm_segment;
      dpmiregs.x.dx = 0;
      dpmiregs.x.ss = dpmiregs.x.sp = 0;
      _go32_dpmi_simulate_int (0x21, &dpmiregs);
      dos_country_code = dpmiregs.x.bx;
      dosmemget (info.rm_segment * 16, DOS_COUNTRY_INFO,
dos_country_info);
      */

      dos_country_code = 1;
      _go32_dpmi_free_dos_memory (&info);
    }

This causes the same startup SIGSEGV that was happening before.

2)  I made the following test program:

/* test.c */

#include <dpmi.h>

int main( void )
{
  _go32_dpmi_seginfo info;

  _go32_dpmi_allocate_dos_memory ( &info );
  _go32_dpmi_free_dos_memory ( &info );

  return( 0 );
}

compiled and ran it:

C:\test>gcc -Wall -o test.exe test.c

C:\test>test
Exiting due to signal SIGSEGV
General Protection Fault at eip=0000346b
eax=000001ef ebx=0004d2c0 ecx=0004a288 edx=000001ef esi=000000d7
edi=0000a2d4
ebp=00043248 esp=00003242 program=C:\TEST\TEST.EXE
cs: sel=00c7  base=00110800  limit=00005ef0
ds: sel=00b7  base=000cc1f0  limit=0000ffff
es: sel=00d7  base=001166f0  limit=00005fff
fs: sel=019f  base=000050b0  limit=0000ffff
gs: sel=01df  base=00000000  limit=7ffeffff
ss: sel=00b7  base=000cc1f0  limit=0000ffff

C:\test>

Okay, let's debug:

C:\test>gcc -Wall -g -o test.exe test.c

C:\test>gdb test.exe
GDB is free software and you are welcome to distribute copies of it
 under certain conditions; type "show copying" to see the conditions.
There is absolutely no warranty for GDB; type "show warranty" for
details.
GDB 4.16 (go32), Copyright 1996 Free Software Foundation, Inc...
(gdb) break main
Breakpoint 1 at 0x155b: file test.c, line 9.
(gdb) run
Starting program: c:/test/test.exe

Breakpoint 1, main () at test.c:9
9         _go32_dpmi_allocate_dos_memory ( &info );
(gdb) step
10        _go32_dpmi_free_dos_memory ( &info );
(gdb) nexti
0x156a  10        _go32_dpmi_free_dos_memory ( &info );
(gdb) nexti
0x156b  10        _go32_dpmi_free_dos_memory ( &info );
(gdb) nexti

Program received signal SIGSEGV, Segmentation fault.
0x346b in _get_volume_info ()
(gdb) info all-registers
eax            0x23f    575
ecx            0x4a288  303752
edx            0x23f    575
ebx            0x4d320  316192
esp            0x2f42   0x2f42
ebp            0x42f48  0x42f48
esi            0xd7     215
edi            0xa2d4   41684
eip            0x346b   0x346b
ps             0x13256  78422
cs             0xc7     199
ss             0xb7     183
ds             0xb7     183
es             0xd7     215
fs             0x217    535
gs             0x237    567
(gdb)

Any suggestions?
Scott

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