Re: What for Break Key No Work?

From	rickman <gnuarm@gmail.com>
Newsgroups	comp.lang.forth
Subject	Re: What for Break Key No Work?
Date	2014-07-27 15:08 -0400
Organization	A noiseless patient Spider
Message-ID	<lr3ino$4pl$1@dont-email.me> (permalink)
References	(16 earlier) <2c176e57-2f20-47df-8293-c2b7860365dd@googlegroups.com> <lqv284$kae$1@dont-email.me> <rfCdnX1GltBJ6k7OnZ2dnUVZ8h6dnZ2d@supernews.com> <lr1pda$8pv$1@dont-email.me> <bdSdnY0o8LxgM0nOnZ2dnUVZ_vGdnZ2d@supernews.com>

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On 7/27/2014 3:49 AM, Andrew Haley wrote:
> rickman <gnuarm@gmail.com> wrote:
>> On 7/26/2014 5:41 AM, Andrew Haley wrote:
>>> rickman <gnuarm@gmail.com> wrote:
>>>>
>>>> Not really.  I understand the difference between the two.  In the
>>>> one case the code in the loop has specific instructions to allow the
>>>> loop to exit when something external sets a flag.  In the case of
>>>> the real time interrupt control is passed to the system we
>>>> determines that the process needs to be "handled".  What I want to
>>>> know is how the process conveys control back to the Forth outer
>>>> interpreter.  The Forth process is stuck in a loop and the CPU is
>>>> now executing the OS.  How does the Forth process return to running
>>>> the interpreter rather than the user code?
>>>
>>> In the simplest case, the signal handler can simply jump to ABORT,
>>> which clears the stacks, resets whatever is necessary, and retuens to
>>> the text interpreter.
>>
>> The "signal handler"...  can you explain what you mean by this?  The
>> Forth program is in a loop.  How does the "signal handler" get invoked?
>
> Say we're running hosted on an OS like UNIX.  (Other OSs are similar,
> but differ in details.)  When Forth starts it registers a handler for
> an INT signal (SIGINT).  When a user hits ctrl-C, the kernel looks for
> a SIGINT handler, finds one, and calls the handler that Forth
> registered.
>
> http://en.wikipedia.org/wiki/Signal_handler

Thanks, I think I am back on solid ground.  The signal is the software 
equivalent of a hardware interrupt.  Rather than restore full context of 
the process, the Cntl-C signal handler is called and in this case would 
end up executing an abort.

I guess I was getting all the details mixed up in my mind about the 
differences of a software signal and a hardware interrupt.  Restoring a 
process to it's state at the time of the interrupt is straight forward. 
  Invoking the signal handler would be rather complex in this case as 
the code can't assume anything about the operating context.  The stack 
pointer may be corrupted and even I/O may have been munged.  Interesting 
problem to deal with.  I hope I don't have to do it ever. lol

-- 

Rick

Thread

What for Break Key No Work? Jason Damisch <jasondamisch@yahoo.com> - 2014-07-22 14:44 -0700
  Re: What for Break Key No Work? Roger Levy <roger.levy@gmail.com> - 2014-07-22 14:50 -0700
    Re: What for Break Key No Work? Jason Damisch <jasondamisch@yahoo.com> - 2014-07-22 15:04 -0700
      Re: What for Break Key No Work? Jason Damisch <jasondamisch@yahoo.com> - 2014-07-22 16:03 -0700
      Re: What for Break Key No Work? BruceMcF <agila61@netscape.net> - 2014-07-22 18:34 -0700
        Re: What for Break Key No Work? Jason Damisch <jasondamisch@yahoo.com> - 2014-07-22 19:32 -0700
          Re: What for Break Key No Work? Spam@ControlQ.com - 2014-07-22 22:43 -0400
            Re: What for Break Key No Work? Jason Damisch <jasondamisch@yahoo.com> - 2014-07-23 09:57 -0700
              Re: What for Break Key No Work? "Elizabeth D. Rather" <erather@forth.com> - 2014-07-23 07:12 -1000
                Re: What for Break Key No Work? Jason Damisch <jasondamisch@yahoo.com> - 2014-07-23 10:15 -0700
          Re: What for Break Key No Work? rickman <gnuarm@gmail.com> - 2014-07-22 22:44 -0400
            Re: What for Break Key No Work? Jason Damisch <jasondamisch@yahoo.com> - 2014-07-23 09:58 -0700
              Re: What for Break Key No Work? "Elizabeth D. Rather" <erather@forth.com> - 2014-07-23 21:28 -1000
          Re: What for Break Key No Work? BruceMcF <agila61@netscape.net> - 2014-07-23 13:12 -0700
            Re: What for Break Key No Work? Jason Damisch <jasondamisch@yahoo.com> - 2014-07-23 14:52 -0700
              Re: What for Break Key No Work? Mark Wills <markwills1970@gmail.com> - 2014-07-24 01:54 -0700
                Re: What for Break Key No Work? rickman <gnuarm@gmail.com> - 2014-07-24 07:54 -0400
                Re: What for Break Key No Work? Mark Wills <markwills1970@gmail.com> - 2014-07-24 06:49 -0700
                Re: What for Break Key No Work? rickman <gnuarm@gmail.com> - 2014-07-24 10:39 -0400
                Re: What for Break Key No Work? bruce.mcfarling@gmail.com - 2014-07-24 08:52 -0700
                Re: What for Break Key No Work? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2014-07-24 13:07 -0500
                Re: What for Break Key No Work? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2014-07-25 10:50 +0000
                Re: What for Break Key No Work? Bernd Paysan <bernd.paysan@gmx.de> - 2014-07-25 14:38 +0200
                Re: What for Break Key No Work? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2014-07-25 17:07 +0000
                Re: What for Break Key No Work? Bernd Paysan <bernd.paysan@gmx.de> - 2014-07-26 00:36 +0200
                Re: What for Break Key No Work? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2014-07-27 13:47 +0000
                Re: What for Break Key No Work? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2014-07-25 09:21 -0500
                Re: What for Break Key No Work? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2014-07-25 17:10 +0000
                Re: What for Break Key No Work? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2014-07-26 04:38 -0500
                Re: What for Break Key No Work? Bernd Paysan <bernd.paysan@gmx.de> - 2014-07-26 15:56 +0200
                Re: What for Break Key No Work? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2014-07-27 13:27 +0000
                Re: What for Break Key No Work? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2014-07-27 09:36 -0500
                Re: What for Break Key No Work? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2014-07-28 11:38 +0000
                Re: What for Break Key No Work? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2014-07-28 10:42 -0500
                Re: What for Break Key No Work? "Rod Pemberton" <dont_use_email@xnothavet.cqm> - 2014-07-25 16:56 -0400
                Re: What for Break Key No Work? "Elizabeth D. Rather" <erather@forth.com> - 2014-07-26 09:33 +0000
                Re: What for Break Key No Work? rickman <gnuarm@gmail.com> - 2014-07-24 19:40 -0400
                Re: What for Break Key No Work? albert@spenarnc.xs4all.nl (Albert van der Horst) - 2014-07-25 00:00 +0000
                Re: What for Break Key No Work? rickman <gnuarm@gmail.com> - 2014-07-24 22:17 -0400
                Re: What for Break Key No Work? bruce.mcfarling@gmail.com - 2014-07-25 06:54 -0700
                Re: What for Break Key No Work? "Elizabeth D. Rather" <erather@forth.com> - 2014-07-25 13:13 -0400
                Re: What for Break Key No Work? rickman <gnuarm@gmail.com> - 2014-07-25 13:24 -0400
                Re: What for Break Key No Work? bruce.mcfarling@gmail.com - 2014-07-25 14:37 -0700
                Re: What for Break Key No Work? rickman <gnuarm@gmail.com> - 2014-07-25 19:01 -0400
                Re: What for Break Key No Work? bruce.mcfarling@gmail.com - 2014-07-25 16:20 -0700
                Re: What for Break Key No Work? rickman <gnuarm@gmail.com> - 2014-07-25 22:02 -0400
                Re: What for Break Key No Work? rickman <gnuarm@gmail.com> - 2014-07-25 22:17 -0400
                Re: What for Break Key No Work? albert@spenarnc.xs4all.nl (Albert van der Horst) - 2014-07-26 09:09 +0000
                Re: What for Break Key No Work? rickman <gnuarm@gmail.com> - 2014-07-26 05:36 -0400
                Re: What for Break Key No Work? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2014-07-26 04:41 -0500
                Re: What for Break Key No Work? rickman <gnuarm@gmail.com> - 2014-07-26 22:50 -0400
                Re: What for Break Key No Work? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2014-07-27 02:49 -0500
                Re: What for Break Key No Work? rickman <gnuarm@gmail.com> - 2014-07-27 15:08 -0400
                Re: What for Break Key No Work? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2014-07-27 14:11 -0500
                Re: What for Break Key No Work? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2014-07-28 12:00 +0000
                Re: What for Break Key No Work? rickman <gnuarm@gmail.com> - 2014-07-28 10:41 -0400
                Re: What for Break Key No Work? Bernd Paysan <bernd.paysan@gmx.de> - 2014-07-27 14:31 +0200
                Re: What for Break Key No Work? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2014-07-27 13:08 +0000
                Re: What for Break Key No Work? albert@spenarnc.xs4all.nl (Albert van der Horst) - 2014-07-27 19:37 +0000
                Re: What for Break Key No Work? rickman <gnuarm@gmail.com> - 2014-07-27 16:35 -0400
                Re: What for Break Key No Work? "Elizabeth D. Rather" <erather@forth.com> - 2014-07-27 22:24 +0000
                Re: What for Break Key No Work? albert@spenarnc.xs4all.nl (Albert van der Horst) - 2014-07-28 13:14 +0000
                Re: What for Break Key No Work? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2014-07-28 03:41 -0500
                Re: What for Break Key No Work? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2014-07-28 12:09 +0000
                Re: What for Break Key No Work? rickman <gnuarm@gmail.com> - 2014-07-28 10:48 -0400
                Re: What for Break Key No Work? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2014-07-28 15:29 +0000
                Re: What for Break Key No Work? rickman <gnuarm@gmail.com> - 2014-07-28 14:30 -0400
                Re: What for Break Key No Work? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2014-07-29 08:12 +0000
                Re: What for Break Key No Work? albert@spenarnc.xs4all.nl (Albert van der Horst) - 2014-07-28 13:10 +0000
                Re: What for Break Key No Work? bruce.mcfarling@gmail.com - 2014-07-27 11:33 -0700
                Re: What for Break Key No Work? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2014-07-28 11:55 +0000
                Re: What for Break Key No Work? "Alex McDonald" <blog@rivadpm.com> - 2014-07-28 14:03 +0100
                Re: What for Break Key No Work? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2014-07-27 13:02 +0000
                Re: What for Break Key No Work? albert@spenarnc.xs4all.nl (Albert van der Horst) - 2014-07-26 08:57 +0000
                Re: What for Break Key No Work? rickman <gnuarm@gmail.com> - 2014-07-26 05:05 -0400
                Re: What for Break Key No Work? albert@spenarnc.xs4all.nl (Albert van der Horst) - 2014-07-26 09:20 +0000
            Re: What for Break Key No Work? "Alex McDonald" <blog@rivadpm.com> - 2014-07-23 23:48 +0100
            Re: What for Break Key No Work? rickman <gnuarm@gmail.com> - 2014-07-24 04:53 -0400
              Re: What for Break Key No Work? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2014-07-24 10:59 +0000
                Re: What for Break Key No Work? mhx@iae.nl - 2014-07-24 04:23 -0700
          Re: What for Break Key No Work? albert@spenarnc.xs4all.nl (Albert van der Horst) - 2014-07-24 19:28 +0000
            Re: What for Break Key No Work? "Elizabeth D. Rather" <erather@forth.com> - 2014-07-24 13:01 -1000
              Re: What for Break Key No Work? Roelf Toxopeus <rt4all@notthis.hetnet.nl> - 2014-07-25 10:13 +0200
      Re: What for Break Key No Work? "Elizabeth D. Rather" <erather@forth.com> - 2014-07-22 17:11 -1000
        Re: What for Break Key No Work? Jason Damisch <jasondamisch@yahoo.com> - 2014-07-23 09:59 -0700
  Re: What for Break Key No Work? David Schultz <abuse@127.0.0.1> - 2014-07-22 17:47 -0500
    Re: What for Break Key No Work? rickman <gnuarm@gmail.com> - 2014-07-22 19:12 -0400
      Re: What for Break Key No Work? Jason Damisch <jasondamisch@yahoo.com> - 2014-07-22 16:21 -0700
        Re: What for Break Key No Work? rickman <gnuarm@gmail.com> - 2014-07-22 22:51 -0400
  Re: What for Break Key No Work? Matthias Trute <matthias.trute@gmail.com> - 2014-07-23 02:18 -0700
  Re: What for Break Key No Work? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2014-07-23 13:21 +0000
    Re: What for Break Key No Work? Jason Damisch <jasondamisch@yahoo.com> - 2014-07-23 10:02 -0700
    Re: What for Break Key No Work? Bernd Paysan <bernd.paysan@gmx.de> - 2014-07-24 04:10 +0200
  Re: What for Break Key No Work? mhx@iae.nl - 2014-07-23 13:45 -0700
  Re: What for Break Key No Work? BruceMcF <agila61@netscape.net> - 2014-07-23 16:37 -0700
  Re: What for Break Key No Work? "Clyde W. Phillips Jr." <cwpjr02@gmail.com> - 2014-07-30 16:13 -0700
  Re: What for Break Key No Work? francois.ganza@wanadoo.fr - 2014-07-30 22:55 -0700

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