From: "Francisco Pastor" <Francisco DOT Pastor AT uv DOT es>
Newsgroups: comp.os.msdos.djgpp
Subject: Problems with rmote debug in gdb
Date: Tue, 17 Jun 2003 09:53:59 +0200
Organization: Universitat de Valencia
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To: djgpp AT delorie DOT com
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Reply-To: djgpp AT delorie DOT com

I am ussing gdb 5.3 with djgpp over Win2K and this do not work in remote
debuging.

Looking what gdb send by the serial link it seems that gdb do not wait for a
response. It send all the retries at one time.

Looking the source in the module ser-go32.c, the function to read a char is:

static int
dos_readchar (struct serial *scb, int timeout)
{
  struct dos_ttystate *port = &ports[scb->fd];
  long then;
  int c;

  then = rawclock () + (timeout * RAWHZ);
  while ((c = dos_getc (port)) < 0)
    {
      if (timeout >= 0 && (rawclock () - then) >= 0)
        return SERIAL_TIMEOUT;
    }

  return c;
}

And this has the problem above. But if I change the code by:

static int
dos_readchar (struct serial *scb, int timeout)
{
  struct dos_ttystate *port = &ports[scb->fd];
  long then;
  int c;

  then = rawclock() + (timeout * RAWHZ);
  for ( ;; )
  {
    c = dos_getc (port);
    if ( c >= 0 ) break;
    if ( timeout < 0 ) continue;
    if ( rawclock() > then ) return SERIAL_TIMEOUT;
  }
  return c;
}

With that the remote debugging work fine.

Both codes seems right. My be a problem with de compiler optimization?
I think that because disaseembling the code produced by the first function
the loop for wait a char o the time-out seems is not correct.

Please, say me if somebody have a similar problem.

Thanks