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Re: OT: ANS Forth

From Bernd Paysan <bernd.paysan@gmx.de>
Newsgroups comp.lang.forth
Subject Re: OT: ANS Forth
Date 2013-02-25 20:57 +0100
Organization 1&1 Internet AG
Message-ID <kggfn4$jcl$1@online.de> (permalink)
References (8 earlier) <kg6e1k$91u$1@online.de> <7xip5jphqn.fsf@ruckus.brouhaha.com> <20130224021232.5736.32397@Nokia-N810-43-7> <kgbvtf$ngn$1@online.de> <2013Feb25.185858@mips.complang.tuwien.ac.at>

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Anton Ertl wrote:
>>This is more bullet-proof to do with values, as you absolutely need a TO
>>to change a value.
> 
> No, there is another way: store to a buggy address.

Or buffer overflows or whatever writes where it shouldn't.

>>The slower way, which is more general, is to pack all watched variables
>>into a specific memory area (trivial), and add code to every ! to check
>>for that
>>area.  If you like a combination with hardware assistance, you could
>>mprotect all your watched variables as read-only, and if the access
>>segfaults, print the diagnistics, mprotect rw, single-step one
>>instruction, and mprotect to ro again.
> 
> Sounds too complicated and may also be quite slow.

The print statement for the diagnostics won't be that fast, either.  You 
have a read-only page, all reads go without delay, and the write is 
segfault+mprotect+single step+mprotect+return from segfault.

Given that you need the OS to set the debug registers, too, this is not any 
slower than using debug registers.

> Given that ! is
> not so frequent in Forth, a check for a simple addres of a range
> should not produce a big slowdown.  There are a few other primitives
> that store to memory (+! MOVE CMOVE CMOVE> READ-FILE, READ-LINE, any
> others?), one would have to add checks to all of them.

If you can make sure that only primitives can access memory, this is 
sufficent.  What about a C interface?

>>Yes.  And they work for any arbitrary pointer calculations, as well as for
>>buffer overflows accidently killing the variable, which no software
>>technique in the world will discover.
> 
> Sure, if you cover every one of these primitives, you are pretty safe;
> ok, a stack could overflow into the place you want to watch if you
> allow setting a stack pointer in the vicinity, but you can protect
> against that, too.

What might be interesting for primitive-supported watchpoints is to 
integrate the tracing, e.g. into a memory buffer.  If you want to record 
significant traces, and observe many variables, the primitive-supported 
trace would be the way to go.

Bill Stoddard does something like this for his reversible Forth: Each store 
records the previous value and the address in the roll-back buffer.

-- 
Bernd Paysan
"If you want it done right, you have to do it yourself"
http://bernd-paysan.de/

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3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-07 22:51 +0100
  Re: 3D-graphics calculations using integers? "Paul E. Bennett" <Paul_E.Bennett@topmail.co.uk> - 2013-02-07 22:08 +0000
  Re: 3D-graphics calculations using integers? AKE <assadebrahim2000@gmail.com> - 2013-02-07 14:32 -0800
    Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-07 23:40 +0100
      Re: 3D-graphics calculations using integers? AKE <assadebrahim2000@gmail.com> - 2013-02-07 17:06 -0800
      Re: 3D-graphics calculations using integers? AKE <assadebrahim2000@gmail.com> - 2013-02-07 17:07 -0800
  Re: 3D-graphics calculations using integers? Pablo Hugo Reda <pabloreda@gmail.com> - 2013-02-07 14:36 -0800
    Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-07 23:46 +0100
      Re: 3D-graphics calculations using integers? "Elizabeth D. Rather" <erather@forth.com> - 2013-02-07 16:38 -1000
        Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-08 10:22 +0100
      Re: 3D-graphics calculations using integers? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-02-08 10:26 +0000
  Re: 3D-graphics calculations using integers? "Elizabeth D. Rather" <erather@forth.com> - 2013-02-07 12:50 -1000
    Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-08 00:15 +0100
      Re: 3D-graphics calculations using integers? kenney@cix.compulink.co.uk - 2013-02-08 14:51 -0600
        Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-08 22:02 +0100
  Re: 3D-graphics calculations using integers? rickman <gnuarm@gmail.com> - 2013-02-07 18:21 -0500
    Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-08 00:30 +0100
      Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-08 00:39 +0100
        Re: 3D-graphics calculations using integers? rickman <gnuarm@gmail.com> - 2013-02-07 18:51 -0500
          Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-08 12:28 +0100
            Re: 3D-graphics calculations using integers? albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-02-08 12:25 +0000
              Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-08 22:04 +0100
                Re: 3D-graphics calculations using integers? albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-02-09 15:27 +0000
                Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-09 16:36 +0100
            Re: 3D-graphics calculations using integers? Mark Wills <forthfreak@gmail.com> - 2013-02-08 05:01 -0800
              Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-08 21:58 +0100
            Re: 3D-graphics calculations using integers? Roberto Waltman <usenet@rwaltman.com> - 2013-02-08 10:08 -0500
              Re: 3D-graphics calculations using integers? Roberto Waltman <usenet@rwaltman.com> - 2013-02-08 10:11 -0500
                Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-08 22:05 +0100
              Re: 3D-graphics calculations using integers? Pablo Hugo Reda <pabloreda@gmail.com> - 2013-02-08 08:29 -0800
                Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-08 18:48 +0100
            Re: 3D-graphics calculations using integers? rickman <gnuarm@gmail.com> - 2013-02-08 17:20 -0500
              Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-08 23:32 +0100
                Re: 3D-graphics calculations using integers? rickman <gnuarm@gmail.com> - 2013-02-09 23:57 -0500
              Re: 3D-graphics calculations using integers? "Elizabeth D. Rather" <erather@forth.com> - 2013-02-08 15:02 -1000
                Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-09 02:24 +0100
                Re: 3D-graphics calculations using integers? "Elizabeth D. Rather" <erather@forth.com> - 2013-02-08 15:58 -1000
                Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-09 16:43 +0100
                Re: 3D-graphics calculations using integers? "Elizabeth D. Rather" <erather@forth.com> - 2013-02-09 10:03 -1000
                Re: 3D-graphics calculations using integers? "Ed" <invalid@nospam.com> - 2013-02-10 11:35 +1100
                Re: 3D-graphics calculations using integers? humptydumpty <ouatubi@gmail.com> - 2013-02-08 23:48 -0800
                Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-09 16:37 +0100
                OT: ANS Forth Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-09 17:27 +0100
                Re: OT: ANS Forth "Elizabeth D. Rather" <erather@forth.com> - 2013-02-09 10:06 -1000
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-09 12:26 -0800
                Re: OT: ANS Forth Elizabeth D Rather <erather@forth.com> - 2013-02-09 14:38 -1000
                Re: OT: ANS Forth "Rod Pemberton" <do_not_have@notemailnotz.cnm> - 2013-02-22 12:52 -0500
                Re: OT: ANS Forth "Elizabeth D. Rather" <erather@forth.com> - 2013-02-22 09:25 -1000
                Re: OT: ANS Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-02-10 08:15 -0600
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-10 23:34 -0800
                Re: OT: ANS Forth Josh Grams <josh@qualdan.com> - 2013-02-11 22:14 +0000
                Re: OT: ANS Forth "Elizabeth D. Rather" <erather@forth.com> - 2013-02-11 13:34 -1000
                Re: OT: ANS Forth "Ed" <invalid@nospam.com> - 2013-02-11 11:52 +1100
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-10 17:11 -0800
                Re: OT: ANS Forth "Elizabeth D. Rather" <erather@forth.com> - 2013-02-10 22:06 -1000
                Re: OT: ANS Forth "Charles Childers" <crc@retroforth.org> - 2013-02-11 17:17 -0500
                Re: OT: ANS Forth "Ed" <invalid@nospam.com> - 2013-02-13 11:42 +1100
                Re: OT: ANS Forth "Elizabeth D. Rather" <erather@forth.com> - 2013-02-12 16:07 -1000
                Re: OT: ANS Forth "Ed" <invalid@nospam.com> - 2013-02-15 09:42 +1100
                Re: OT: ANS Forth Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-15 00:16 +0100
                Re: OT: ANS Forth "Ed" <invalid@nospam.com> - 2013-02-17 16:05 +1100
                Re: OT: ANS Forth Howerd <howerdo@yahoo.co.uk> - 2013-02-17 04:16 -0800
                Re: OT: ANS Forth albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-02-17 13:12 +0000
                Re: OT: ANS Forth Howerd <howerdo@yahoo.co.uk> - 2013-02-17 09:15 -0800
                Re: OT: ANS Forth Brad Eckert <hwfwguy@gmail.com> - 2013-02-19 09:35 -0800
                Re: OT: ANS Forth Andy Valencia <user@vsta.org> - 2013-02-19 19:25 +0000
                Re: OT: ANS Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-02-19 15:35 -0600
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-21 00:37 -0800
                Re: OT: ANS Forth "Elizabeth D. Rather" <erather@forth.com> - 2013-02-20 23:07 -1000
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-21 01:38 -0800
                Re: OT: ANS Forth "Elizabeth D. Rather" <erather@forth.com> - 2013-02-21 08:50 -1000
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-23 15:44 -0800
                Re: OT: ANS Forth albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-02-24 03:41 +0000
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-23 20:00 -0800
                Re: OT: ANS Forth stephenXXX@mpeforth.com (Stephen Pelc) - 2013-02-24 13:49 +0000
                Re: OT: ANS Forth albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-02-24 15:04 +0000
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-24 14:52 -0800
                Re: OT: ANS Forth albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-02-24 23:51 +0000
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-24 16:23 -0800
                Re: OT: ANS Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-02-21 03:55 -0600
                Re: OT: ANS Forth "Rod Pemberton" <do_not_have@notemailnotz.cnm> - 2013-02-22 13:01 -0500
                Re: OT: ANS Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-02-22 12:26 -0600
                Re: OT: ANS Forth Andy Valencia <user@vsta.org> - 2013-02-19 21:54 +0000
                Re: OT: ANS Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-02-19 18:21 -0600
                Re: OT: ANS Forth Brad Eckert <hwfwguy@gmail.com> - 2013-02-20 08:45 -0800
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-20 11:01 -0800
                Re: OT: ANS Forth "Elizabeth D. Rather" <erather@forth.com> - 2013-02-20 11:25 -1000
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-21 00:22 -0800
                Re: OT: ANS Forth "Elizabeth D. Rather" <erather@forth.com> - 2013-02-20 22:50 -1000
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-21 01:08 -0800
                Re: OT: ANS Forth albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-02-21 12:42 +0000
                Re: OT: ANS Forth Bernd Paysan <bernd.paysan@gmx.de> - 2013-02-21 13:50 +0100
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-21 09:36 -0800
                Re: OT: ANS Forth Bernd Paysan <bernd.paysan@gmx.de> - 2013-02-22 01:32 +0100
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-23 00:50 -0800
                Re: OT: ANS Forth Bernd Paysan <bernd.paysan@gmx.de> - 2013-02-24 03:03 +0100
                Re: OT: ANS Forth Brad Eckert <hwfwguy@gmail.com> - 2013-02-21 09:12 -0800
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-23 00:38 -0800
                Re: OT: ANS Forth "Elizabeth D. Rather" <erather@forth.com> - 2013-02-21 09:01 -1000
                Re: OT: ANS Forth mhx@iae.nl (Marcel Hendrix) - 2013-02-22 00:05 +0200
                Re: OT: ANS Forth Bernd Paysan <bernd.paysan@gmx.de> - 2013-02-21 13:24 +0100
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-21 09:33 -0800
                Re: OT: ANS Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-02-21 13:04 -0600
                Re: OT: ANS Forth Bernd Paysan <bernd.paysan@gmx.de> - 2013-02-22 01:41 +0100
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-23 00:31 -0800
                Re: OT: ANS Forth "Paul E. Bennett" <Paul_E.Bennett@topmail.co.uk> - 2013-02-23 09:15 +0000
                Re: OT: ANS Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-02-23 04:33 -0600
                Re: OT: ANS Forth albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-02-23 13:49 +0000
                Re: OT: ANS Forth Roberto Waltman <usenet@rwaltman.com> - 2013-02-23 13:35 -0500
                Re: OT: ANS Forth Roberto Waltman <usenet@rwaltman.com> - 2013-02-23 13:46 -0500
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-23 15:26 -0800
                Re: OT: ANS Forth Roberto Waltman <usenet@rwaltman.com> - 2013-02-24 09:41 -0500
                Re: OT: ANS Forth "Elizabeth D. Rather" <erather@forth.com> - 2013-02-21 09:09 -1000
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-23 00:37 -0800
                Re: OT: ANS Forth albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-02-23 13:57 +0000
                Re: OT: ANS Forth "Elizabeth D. Rather" <erather@forth.com> - 2013-02-23 08:47 -1000
                Re: OT: ANS Forth Bernd Paysan <bernd.paysan@gmx.de> - 2013-02-22 01:27 +0100
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-23 00:16 -0800
                Re: OT: ANS Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-02-23 04:36 -0600
                Re: OT: ANS Forth anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-02-23 16:52 +0000
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-23 12:39 -0800
                Re: OT: ANS Forth anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-02-25 16:27 +0000
                Re: OT: ANS Forth "Rod Pemberton" <do_not_have@notemailnotz.cnm> - 2013-02-23 18:08 -0500
                Re: OT: ANS Forth Bernd Paysan <bernd.paysan@gmx.de> - 2013-02-24 02:20 +0100
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-24 20:16 -0800
                Re: OT: ANS Forth Bernd Paysan <bernd.paysan@gmx.de> - 2013-02-25 16:04 +0100
                Re: OT: ANS Forth albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-02-25 17:12 +0000
                Re: OT: ANS Forth Bernd Paysan <bernd.paysan@gmx.de> - 2013-02-25 20:44 +0100
                Re: OT: ANS Forth Bernd Paysan <bernd.paysan@gmx.de> - 2013-02-25 16:45 +0100
                Re: OT: ANS Forth Andy Valencia <user@vsta.org> - 2013-02-24 02:09 +0000
                Re: OT: ANS Forth Bernd Paysan <bernd.paysan@gmx.de> - 2013-02-24 04:03 +0100
                Re: OT: ANS Forth anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-02-25 17:58 +0000
                Re: OT: ANS Forth Bernd Paysan <bernd.paysan@gmx.de> - 2013-02-25 20:57 +0100
                Re: OT: ANS Forth anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-03-02 16:43 +0000
                Re: OT: ANS Forth Bernd Paysan <bernd.paysan@gmx.de> - 2013-03-02 18:14 +0100
                Re: OT: ANS Forth anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-03-03 13:56 +0000
                Re: OT: ANS Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-02-24 03:45 -0600
                Re: OT: ANS Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-02-13 04:12 -0600
                Re: OT: ANS Forth stephenXXX@mpeforth.com (Stephen Pelc) - 2013-02-13 12:24 +0000
                Re: OT: ANS Forth anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-02-11 14:41 +0000
                Re: OT: ANS Forth Andy Valencia <user@vsta.org> - 2013-02-11 19:44 +0000
                Re: OT: ANS Forth albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-02-11 21:14 +0000
                Re: 3D-graphics calculations using integers? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-02-09 18:14 -0600
                Re: 3D-graphics calculations using integers? rickman <gnuarm@gmail.com> - 2013-02-10 00:06 -0500

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