* Diff between 11/20 and 11/45?
@ 1999-09-08 17:00 Steven M. Schultz
0 siblings, 0 replies; 3+ messages in thread
From: Steven M. Schultz @ 1999-09-08 17:00 UTC (permalink / raw)
Hi -
> From: Dave Horsfall <dave at fgh.geac.com.au>
> Do you recall the PC-board hack on the sep-ID machines that changed
No, I do not recall seeing a PCB hack (hacking on an 11/70 was
frowned upon ;))
> the MFPI instruction to do something that was expressly prohibited?
But I do know what that 'something' was. In "user" or "supervisor"
mode MPFI functioned as "MFPD" - a user program could not read its own
I(nstruction) space. Only for "kernel" mode did MFPI access the
I space.
> Something about allowing a user program to access something else, for
> some obscure hack or other...
It was aimed at providing "execute only" code - a program could "run"
but not "read" its code space.
This caused problems though if trap handlers (floating point exception
handling comes to mind) needed to retrieve the faulted instruction
for inspection/analysis. Thus in 2BSD there is a system call that
programs can issue to request the KERNEL to do the 'mfpi' for them
and return the value.
Steven Schultz
sms at moe.2bsd.com
Received: (from major at localhost)
by minnie.cs.adfa.edu.au (8.9.3/8.9.3) id TAA10091
for pups-liszt; Thu, 9 Sep 1999 19:48:18 +1000 (EST)
Received: from Zeke.Update.UU.SE (IDENT:2026 at Zeke.Update.UU.SE [130.238.11.14])
by minnie.cs.adfa.edu.au (8.9.3/8.9.3) with ESMTP id TAA10087
for <pups at minnie.cs.adfa.edu.au>; Thu, 9 Sep 1999 19:48:09 +1000 (EST)
Received: from localhost (bqt at localhost)
by Zeke.Update.UU.SE (8.8.8/8.8.8) with SMTP id LAA22975;
Thu, 9 Sep 1999 11:58:20 +0200
Date: Thu, 9 Sep 1999 11:58:19 +0200 (MET DST)
From: Johnny Billquist <bqt@Update.UU.SE>
To: Warren Toomey <wkt at cs.adfa.edu.au>
cc: Unix Heritage Society <pups at minnie.cs.adfa.edu.au>
Subject: Re: Diff between 11/20 and 11/45?
In-Reply-To: <199909062356.JAA12397 at henry.cs.adfa.edu.au>
Message-ID: <Pine.VUL.3.93.990909115534.22939A-100000 at Zeke.Update.UU.SE>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII
Sender: owner-pups at minnie.cs.adfa.edu.au
Precedence: bulk
On Tue, 7 Sep 1999, Warren Toomey wrote:
> These executables were written for a PDP-11/20. Are there any significant
> USER-MODE differences between the 11/20 and later PDP-11 models? I'm
> thinking missing instructions, different addressing mode behaviour etc.
As far as I can remember, there aren't any huge differences. However, some
stuff behave differently in the 11/20. On the other hand, some stuff
behave differently in just about every implementation...
Condition flags on some instructions specifically. And the 11/20 might
have had some limitations on using the PC which differed as well.
I have a processor handbook for the "modern" -11s, which has a chart with
all differences between different models. I started writing it down, to
place in the PDP-11 FAQ, but haven't come that far yet...
Johnny
Johnny Billquist || "I'm on a bus
|| on a psychedelic trip
email: bqt at update.uu.se || Reading murder books
pdp is alive! || tryin' to stay hip" - B. Idol
^ permalink raw reply [flat|nested] 3+ messages in thread
* Diff between 11/20 and 11/45?
@ 1999-09-07 6:04 Carl Lowenstein
0 siblings, 0 replies; 3+ messages in thread
From: Carl Lowenstein @ 1999-09-07 6:04 UTC (permalink / raw)
> From: Warren Toomey <wkt at cs.adfa.edu.au>
> Subject: Diff between 11/20 and 11/45?
> To: pups at minnie.cs.adfa.edu.au (Unix Heritage Society)
> Date: Tue, 7 Sep 1999 09:56:09 +1000 (EST)
>
> Dennis Ritchie has unearthed some really old Unix a.out
> executables from around 1st Edition - 2nd Edition period: see
> Distributions/research/1973_stuff in the PUPS Archive.
>
> These executables were written for a PDP-11/20. Are there any significant
> USER-MODE differences between the 11/20 and later PDP-11 models? I'm
> thinking missing instructions, different addressing mode behaviour etc.
There's a good table in the back of the more recent micro-11 manuals.
The first genuine user-mode difference that I remember coming across was
an incompatibility in the result of
MOV SP, -(SP)
It isn't really clear to me why one would want to use this particular
instruction, however it turned out to hang both BASIC and FOCAL at the
time. A zero-length patch wasn't too hard to figure out.
carl
carl lowenstein marine physical lab u.c. san diego
{decvax|ucbvax} !ucsd!mpl!cdl cdl at mpl.ucsd.edu
clowenstein at ucsd.edu
Received: (from major at localhost)
by minnie.cs.adfa.edu.au (8.9.3/8.9.3) id KAA03173
for pups-liszt; Wed, 8 Sep 1999 10:13:57 +1000 (EST)
Received: from psychwarp.psych.usyd.edu.au (psychwarp.psych.usyd.edu.au [129.78.83.26])
by minnie.cs.adfa.edu.au (8.9.3/8.9.3) with ESMTP id KAA03169
for <pups at minnie.cs.adfa.edu.au>; Wed, 8 Sep 1999 10:13:51 +1000 (EST)
Received: (from johnh at localhost)
by psychwarp.psych.usyd.edu.au (8.9.1a/8.9.1) id LAA09862
for pups at minnie.cs.adfa.edu.au; Tue, 7 Sep 1999 11:28:16 +1000 (EST)
Date: Tue, 7 Sep 1999 11:28:16 +1000 (EST)
From: johnh@psych.usyd.edu.au
Message-Id: <199909070128.LAA09862 at psychwarp.psych.usyd.edu.au>
To: pups at minnie.cs.adfa.edu.au
Subject: Re: Diff between 11/20 and 11/45
Sender: owner-pups at minnie.cs.adfa.edu.au
Precedence: bulk
There is huge difference between the machines, but not backwards!
The 11/20 doesn't have :-
EIS instructions like div, mul, ash etc
FPU instructions like fmul ...
MMU no memory management of any sort, 56Kb memory, 8Kb I/O page
and hence no user modes, 16 bit addressing
So a program written for a 11/20 should work untouched on an 11/45 except for
some very minor (and ugly) instruction sequences involving using the same
register for both source and destination eg mov r2,-(r2), or jmp (r2)+.
The behaviour of the trace trap and T bit is also different.
There is a list of differences some some of the PDP/11 handbooks (perhaps the
latter architecture book).
Received: (from major at localhost)
by minnie.cs.adfa.edu.au (8.9.3/8.9.3) id KAA03319
for pups-liszt; Wed, 8 Sep 1999 10:38:29 +1000 (EST)
Received: from caveman.geac.com.au (caveman.geac.com.au [203.30.73.2])
by minnie.cs.adfa.edu.au (8.9.3/8.9.3) with SMTP id KAA03314
for <pups at minnie.cs.adfa.edu.au>; Wed, 8 Sep 1999 10:38:20 +1000 (EST)
Received: (qmail 4222 invoked from network); 8 Sep 1999 10:56:15 +1000
Received: from trowel.geac.com.au (203.1.26.189)
by caveman.geac.com.au with SMTP; 8 Sep 1999 10:56:15 +1000
Received: (qmail 27184 invoked from network); 8 Sep 1999 11:04:35 +1000
Received: from fgh.geac.com.au (202.6.67.163)
by trowel.geac.com.au with SMTP; 8 Sep 1999 11:04:35 +1000
Received: from localhost (dave at localhost)
by fgh.geac.com.au?r with ESMTP id KAA21475
for <pups at minnie.cs.adfa.edu.au>; Wed, 8 Sep 1999 10:50:40 +1000
X-Envelope-From: dave at horsfall.org
X-Envelope-To: <pups at minnie.cs.adfa.edu.au>
X-Authentication-Warning: fgh.geac.com.au: dave owned process doing -bs
Date: Wed, 8 Sep 1999 10:50:39 +1000 (EST)
From: Dave Horsfall <dave@fgh.geac.com.au>
X-Sender: dave at fgh
To: PDP Unix Preservation Society <pups at minnie.cs.adfa.edu.au>
Subject: Re: KE11-A! (was Diff between 11/20 and 11/45?)
In-Reply-To: <199909070110.LAA12638 at henry.cs.adfa.edu.au>
Message-ID: <Pine.GSO.4.10.9909081049430.19899-100000 at fgh>
X-No-Archive: Yes
X-Witty-Saying: "Tesseract - Enter at own risk"
X-Disclaimer: "Me, speak for us?"
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII
Sender: owner-pups at minnie.cs.adfa.edu.au
Precedence: bulk
On Tue, 7 Sep 1999, Warren Toomey wrote:
> I also see that unit 1 lives at 777300 - 777316, and the date a.out
> executable does this:
Yep; I read through my own 11/20 handbook, and I remembered that
EAE weirdness.
--
Dave Horsfall VK2KFU dave at geac.com.au Ph: +61 2 9978-7493 Fx: +61 2 9978-7422
Geac Computers P/L (FGH Division) 2/57 Christie St, St Leonards 2065, Australia
Received: (from major at localhost)
by minnie.cs.adfa.edu.au (8.9.3/8.9.3) id KAA03361
for pups-liszt; Wed, 8 Sep 1999 10:43:07 +1000 (EST)
Received: from moe.2bsd.com (0 at MOE.2BSD.COM [206.139.202.200])
by minnie.cs.adfa.edu.au (8.9.3/8.9.3) with ESMTP id KAA03354
for <pups at minnie.cs.adfa.edu.au>; Wed, 8 Sep 1999 10:42:59 +1000 (EST)
Received: (from sms at localhost)
by moe.2bsd.com (8.9.0/8.9.0) id RAA15948
for pups at minnie.cs.adfa.edu.au; Tue, 7 Sep 1999 17:49:36 -0700 (PDT)
Date: Tue, 7 Sep 1999 17:49:36 -0700 (PDT)
From: "Steven M. Schultz" <sms@moe.2bsd.com>
Message-Id: <199909080049.RAA15948 at moe.2bsd.com>
To: pups at minnie.cs.adfa.edu.au
Subject: Re: Diff between 11/20 and 11/45?
Sender: owner-pups at minnie.cs.adfa.edu.au
Precedence: bulk
> From: Carl Lowenstein <cdl at mpl.ucsd.edu>
> The first genuine user-mode difference that I remember coming across was
> an incompatibility in the result of
>
> MOV SP, -(SP)
Similarily
MOV R0,(R0)+
won't work as expected on some 11s. I suspect that the even less
likely case of "mov pc,-(pc)" won't work either :-)
> It isn't really clear to me why one would want to use this particular
> instruction, however it turned out to hang both BASIC and FOCAL at the
Fairly common when setting up call frames, etc. You want the
address of where the arguments start and since they're pushed on the
stack 'sp' is the value you want.
There's a comment in 2BSD (I think it came from V7) where mention is
made that "we can't do sp,-(sp) because it won't work on the 11/40".
> time. A zero-length patch wasn't too hard to figure out.
Hmmm, interesting. The workaround I saw took an extra instruction.
Steven Schultz
sms at moe.2bsd.com
Received: (from major at localhost)
by minnie.cs.adfa.edu.au (8.9.3/8.9.3) id KAA03462
for pups-liszt; Wed, 8 Sep 1999 10:53:48 +1000 (EST)
Received: from psychwarp.psych.usyd.edu.au (psychwarp.psych.usyd.edu.au [129.78.83.26])
by minnie.cs.adfa.edu.au (8.9.3/8.9.3) with ESMTP id KAA03458
for <pups at minnie.cs.adfa.edu.au>; Wed, 8 Sep 1999 10:53:43 +1000 (EST)
Received: (from johnh at localhost)
by psychwarp.psych.usyd.edu.au (8.9.1a/8.9.1) id LAA22126
for pups at minnie.cs.adfa.edu.au; Wed, 8 Sep 1999 11:07:37 +1000 (EST)
Date: Wed, 8 Sep 1999 11:07:37 +1000 (EST)
From: johnh@psych.usyd.edu.au
Message-Id: <199909080107.LAA22126 at psychwarp.psych.usyd.edu.au>
To: pups at minnie.cs.adfa.edu.au
Subject: Re: KE11-A! (was Diff between 11/20 and 11/45?)
Sender: owner-pups at minnie.cs.adfa.edu.au
Precedence: bulk
Are, I was afraid of that. The KE11-A wasn't a real CPU option, but
was a peripheral that sat on the Unibus
Received: (from major at localhost)
by minnie.cs.adfa.edu.au (8.9.3/8.9.3) id KAA03506
for pups-liszt; Wed, 8 Sep 1999 10:58:18 +1000 (EST)
Received: from timaxp.trailing-edge.com (timaxp.trailing-edge.com [63.73.218.130])
by minnie.cs.adfa.edu.au (8.9.3/8.9.3) with SMTP id KAA03501
for <PUPS at MINNIE.CS.ADFA.edu.AU>; Wed, 8 Sep 1999 10:58:10 +1000 (EST)
Received: by timaxp.trailing-edge.com for PUPS at MINNIE.CS.ADFA.edu.AU;
Tue, 7 Sep 1999 21:12:00 -0400
Date: Tue, 7 Sep 1999 21:12:00 -0400
From: Tim Shoppa <SHOPPA@trailing-edge.com>
To: PUPS at minnie.cs.adfa.edu.au
Message-Id: <990907211200.2020016c at trailing-edge.com>
Subject: Re: Diff between 11/20 and 11/45?
Sender: owner-pups at minnie.cs.adfa.edu.au
Precedence: bulk
>These executables were written for a PDP-11/20. Are there any significant
>USER-MODE differences between the 11/20 and later PDP-11 models? I'm
>thinking missing instructions, different addressing mode behaviour etc.
Well, first of all, there is no "User mode" on the 11/20 unless you have
a KT11 installed. Everything is kernel mode with no KT11. Maybe the
executables are trying to go out and directly bang on the console CSR's,
the switch register, or the interrupt vectors themselves?
11/20's also frequently had the EAE (Extended Arithmetic Element)
installed, to make up for the fact that there was no multiply, divide,
or multiple shift instructions in the native instruction set (and
wouldn't be until the EIS came along.) The EAE was a peripheral
living in I/O space (773000-777316); you wrote the operands to the EAE
locations and read the results later. You can put a EAE in a machine
with EIS, but generally you only did this if you had some binaries without
sources using the EAE (I know of several sites running 11/24's and 11/44's
with EAE's today)
There are many other differences, especially dealing with "funny" address
modes. Generally, folks like me who have to code so that something works
across all the -11's know better than to do these things, but back when
there was *only* the 11/20 some folks didn't know any better and used
them anyway.
First, we have instructions that use the same register as source
and destination, with an auto-increment one or the other:
1. OPR R,(R)+ on an 11/20 increments R before it's used as a source
operand. On an 11/45 the initial contents of R are used.
2. Same thing for OPR R,-(R).
3. JMP (R)+ or JSR reg,(R)+ increments R before putting it in the PC
on the 11/20; on the 11/45 R isn't incremented until after the old
value is put in the PC.
4. On an 11/20, JMP %R traps to 4; on an 11/45, JMP %R traps to 10
5. On an 11/20, SWAB does not change the V flag; on every other machine,
SWAB clears V. (In the 11/20 processor handbook, it *says* that SWAB
clears the V flag, but that's not the way the machine actually worked!)
6. On an 11/20, R0-R7 can be used by the program at addresses 177700-
177717; on any other machine, they can't be used that way and will
result in a non-existent memory (NXM) trap. This can be used for some
neat tricks where you run code out of the registers (which of course
is quite non-portable!)
There's lots more differences, having to do with T bits and interrupt
handling, but I don't know if you're getting that far... and these
aren't things that you have to worry about in user mode, anyway.
--
Tim Shoppa Email: shoppa at trailing-edge.com
Trailing Edge Technology WWW: http://www.trailing-edge.com/
7328 Bradley Blvd Voice: 301-767-5917
Bethesda, MD, USA 20817 Fax: 301-767-5927
Received: (from major at localhost)
by minnie.cs.adfa.edu.au (8.9.3/8.9.3) id LAA03564
for pups-liszt; Wed, 8 Sep 1999 11:03:51 +1000 (EST)
Received: from caveman.geac.com.au (caveman.geac.com.au [203.30.73.2])
by minnie.cs.adfa.edu.au (8.9.3/8.9.3) with SMTP id LAA03558
for <pups at minnie.cs.adfa.edu.au>; Wed, 8 Sep 1999 11:03:40 +1000 (EST)
Received: (qmail 4832 invoked from network); 8 Sep 1999 11:21:32 +1000
Received: from trowel.geac.com.au (203.1.26.189)
by caveman.geac.com.au with SMTP; 8 Sep 1999 11:21:32 +1000
Received: (qmail 27748 invoked from network); 8 Sep 1999 11:29:48 +1000
Received: from fgh.geac.com.au (202.6.67.163)
by trowel.geac.com.au with SMTP; 8 Sep 1999 11:29:49 +1000
Received: from localhost (dave at localhost)
by fgh.geac.com.au?r with ESMTP id LAA21756
for <pups at minnie.cs.adfa.edu.au>; Wed, 8 Sep 1999 11:15:48 +1000
X-Envelope-From: dave at horsfall.org
X-Envelope-To: <pups at minnie.cs.adfa.edu.au>
X-Authentication-Warning: fgh.geac.com.au: dave owned process doing -bs
Date: Wed, 8 Sep 1999 11:15:48 +1000 (EST)
From: Dave Horsfall <dave@fgh.geac.com.au>
X-Sender: dave at fgh
To: PDP Unix Preservation Society <pups at minnie.cs.adfa.edu.au>
Subject: Re: Diff between 11/20 and 11/45?
In-Reply-To: <199909070604.XAA04723 at mpl.ucsd.edu>
Message-ID: <Pine.GSO.4.10.9909081103330.19899-100000 at fgh>
X-No-Archive: Yes
X-Witty-Saying: "Tesseract - Enter at own risk"
X-Disclaimer: "Me, speak for us?"
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII
Sender: owner-pups at minnie.cs.adfa.edu.au
Precedence: bulk
On Mon, 6 Sep 1999, Carl Lowenstein wrote:
> The first genuine user-mode difference that I remember coming across was
> an incompatibility in the result of
>
> MOV SP, -(SP)
Anything involving the same register as src and dst in this way was,
err, different...
And I have an annotation that the JSR does not behave as documented.
Unlike page 91, the sequence is not (tmp) <- (dst) / v(SP) <- reg /
reg <- PC / PC <- (tmp). The first ISP code is not present i.e. the
SP is decremented first, not saved, and the last is PC <- (dst).
> It isn't really clear to me why one would want to use this particular
> instruction, however it turned out to hang both BASIC and FOCAL at the
> time. A zero-length patch wasn't too hard to figure out.
Some sort of frame pointer linking, on an architecture that didn't
have separate frame pointers (like the Vax)?
--
Dave Horsfall VK2KFU dave at geac.com.au Ph: +61 2 9978-7493 Fx: +61 2 9978-7422
Geac Computers P/L (FGH Division) 2/57 Christie St, St Leonards 2065, Australia
Received: (from major at localhost)
by minnie.cs.adfa.edu.au (8.9.3/8.9.3) id LAA03594
for pups-liszt; Wed, 8 Sep 1999 11:05:14 +1000 (EST)
Received: from timaxp.trailing-edge.com (timaxp.trailing-edge.com [63.73.218.130])
by minnie.cs.adfa.edu.au (8.9.3/8.9.3) with SMTP id LAA03588
for <PUPS at MINNIE.CS.ADFA.edu.AU>; Wed, 8 Sep 1999 11:05:07 +1000 (EST)
Received: by timaxp.trailing-edge.com for PUPS at MINNIE.CS.ADFA.edu.AU;
Tue, 7 Sep 1999 20:48:50 -0400
Date: Tue, 7 Sep 1999 20:48:50 -0400
From: Tim Shoppa <SHOPPA@trailing-edge.com>
To: PUPS at minnie.cs.adfa.edu.au
Message-Id: <990907204850.202001b4 at trailing-edge.com>
Subject: Re: Diff between 11/20 and 11/45?
Sender: owner-pups at minnie.cs.adfa.edu.au
Precedence: bulk
> MOV SP, -(SP)
>
>It isn't really clear to me why one would want to use this particular
>instruction
"MOV SP" is often-used shorthand for "MOV some-non-zero-value", since no
sane implementation would ever have a zero in the SP. So this would
put a non-zero value on top of the stack (perhaps as a flag, to be
cleared by CLR (SP) when ready) - at least on machines where this was legal!
On which machine does this fail, BTW? On a 11/15, 11/20, 11/23, 11/35
or 11/40 this ought to work, decrementing SP by two before putting it on
the stack, and on the 11/03, 11/04, 11/05, 11/10, 11/34, and 11/45
SP is decremented by two before being put on the stack, according to my
notes.
--
Tim Shoppa Email: shoppa at trailing-edge.com
Trailing Edge Technology WWW: http://www.trailing-edge.com/
7328 Bradley Blvd Voice: 301-767-5917
Bethesda, MD, USA 20817 Fax: 301-767-5927
Received: (from major at localhost)
by minnie.cs.adfa.edu.au (8.9.3/8.9.3) id LAA03973
for pups-liszt; Wed, 8 Sep 1999 11:47:41 +1000 (EST)
Received: from caveman.geac.com.au (caveman.geac.com.au [203.30.73.2])
by minnie.cs.adfa.edu.au (8.9.3/8.9.3) with SMTP id LAA03969
for <pups at minnie.cs.adfa.edu.au>; Wed, 8 Sep 1999 11:47:34 +1000 (EST)
Received: (qmail 24470 invoked from network); 7 Sep 1999 14:18:39 +1000
Received: from trowel.geac.com.au (203.1.26.189)
by caveman.geac.com.au with SMTP; 7 Sep 1999 14:18:39 +1000
Received: (qmail 12323 invoked from network); 7 Sep 1999 14:26:41 +1000
Received: from fgh.geac.com.au (202.6.67.163)
by trowel.geac.com.au with SMTP; 7 Sep 1999 14:26:41 +1000
Received: from localhost (dave at localhost)
by fgh.geac.com.au?r with ESMTP id OAA21437
for <pups at minnie.cs.adfa.edu.au>; Tue, 7 Sep 1999 14:13:31 +1000
X-Envelope-From: dave at horsfall.org
X-Envelope-To: <pups at minnie.cs.adfa.edu.au>
X-Authentication-Warning: fgh.geac.com.au: dave owned process doing -bs
Date: Tue, 7 Sep 1999 14:13:30 +1000 (EST)
From: Dave Horsfall <dave@fgh.geac.com.au>
X-Sender: dave at fgh
To: PDP Unix Preservation Society <pups at minnie.cs.adfa.edu.au>
Subject: Re: Diff between 11/20 and 11/45?
In-Reply-To: <199909062356.JAA12397 at henry.cs.adfa.edu.au>
Message-ID: <Pine.GSO.4.10.9909071404290.19123-100000 at fgh>
X-No-Archive: Yes
X-Witty-Saying: "Tesseract - Enter at own risk"
X-Disclaimer: "Me, speak for us?"
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII
Sender: owner-pups at minnie.cs.adfa.edu.au
Precedence: bulk
On Tue, 7 Sep 1999, Warren Toomey wrote:
> I've got a few working. cat works. ls and date run, but sort of give
> strange outputs.
What sort of strange output? My guess is that kernel-wise, date-handling
would have changed.
> These executables were written for a PDP-11/20. Are there any significant
> USER-MODE differences between the 11/20 and later PDP-11 models? I'm
> thinking missing instructions, different addressing mode behaviour etc.
Ummm... No floating point (all emulated), and I seem to recall that
it didn't even have multiply/divide; could this be the problem? The
/20 was certainly a subset of the "classic" 11. No memory management,
but users won't see that. Also had some quirks, long-forgotten.
My experience is based on the GT-40, which was basically a /20 with a
graphics processor attached to it (which had a mean Lunar Lander game!).
--
Dave Horsfall VK2KFU dave at geac.com.au Ph: +61 2 9978-7493 Fx: +61 2 9978-7422
Geac Computers P/L (FGH Division) 2/57 Christie St, St Leonards 2065, Australia
Received: (from major at localhost)
by minnie.cs.adfa.edu.au (8.9.3/8.9.3) id OAA04594
for pups-liszt; Wed, 8 Sep 1999 14:30:23 +1000 (EST)
Received: from mpl.ucsd.edu (chiton.ucsd.edu [192.135.238.128])
by minnie.cs.adfa.edu.au (8.9.3/8.9.3) with ESMTP id OAA04581
for <pups at minnie.cs.adfa.edu.au>; Wed, 8 Sep 1999 14:29:58 +1000 (EST)
Received: (from cdl at localhost)
by mpl.ucsd.edu (8.8.8+Sun/8.8.8) id VAA07676
for pups at minnie.cs.adfa.edu.au; Tue, 7 Sep 1999 21:43:16 -0700 (PDT)
Date: Tue, 7 Sep 1999 21:43:16 -0700 (PDT)
From: Carl Lowenstein <cdl@mpl.ucsd.edu>
Message-Id: <199909080443.VAA07676 at mpl.ucsd.edu>
To: pups at minnie.cs.adfa.edu.au
Subject: Re: Diff between 11/20 and 11/45?
Sender: owner-pups at minnie.cs.adfa.edu.au
Precedence: bulk
> From owner-pups at minnie.cs.adfa.edu.au Tue Sep 7 18:24 PDT 1999
> Date: Tue, 7 Sep 1999 17:49:36 -0700 (PDT)
> From: "Steven M. Schultz" <sms at moe.2bsd.com>
> To: pups at minnie.cs.adfa.edu.au
> Subject: Re: Diff between 11/20 and 11/45?
>
> > From: Carl Lowenstein <cdl at mpl.ucsd.edu>
> >
> > MOV SP, -(SP)
>
> Similarily
>
> MOV R0,(R0)+
>
> won't work as expected on some 11s. I suspect that the even less
> likely case of "mov pc,-(pc)" won't work either :-)
>
> > It isn't really clear to me why one would want to use this particular
> > instruction, however it turned out to hang both BASIC and FOCAL at the
>
> Fairly common when setting up call frames, etc. You want the
> address of where the arguments start and since they're pushed on the
> stack 'sp' is the value you want.
>
> There's a comment in 2BSD (I think it came from V7) where mention is
> made that "we can't do sp,-(sp) because it won't work on the 11/40".
>
> > time. A zero-length patch wasn't too hard to figure out.
>
> Hmmm, interesting. The workaround I saw took an extra instruction.
Abbreviated due to fading memory over the years, but refreshed by some
of the current discussion. The patch was zero-length but involved more
than the one instruction. Something similar to:
MOV SP, -(SP) MOV SP, R0
MOV (sP), R0 MOV R0, -(SP)
The net result being that the initial value of SP is now both in R0 and
on the stack. Without doing both a SRC and DST operation on SP in the
same instruction, which is the thing that is incompatible across different
processor hardware.
carl
Received: (from major at localhost)
by minnie.cs.adfa.edu.au (8.9.3/8.9.3) id OAA04681
for pups-liszt; Wed, 8 Sep 1999 14:51:11 +1000 (EST)
Received: from mpl.ucsd.edu (chiton.ucsd.edu [192.135.238.128])
by minnie.cs.adfa.edu.au (8.9.3/8.9.3) with ESMTP id OAA04676
for <pups at minnie.cs.adfa.edu.au>; Wed, 8 Sep 1999 14:50:06 +1000 (EST)
Received: (from cdl at localhost)
by mpl.ucsd.edu (8.8.8+Sun/8.8.8) id WAA08055
for pups at minnie.cs.adfa.edu.au; Tue, 7 Sep 1999 22:03:09 -0700 (PDT)
Date: Tue, 7 Sep 1999 22:03:09 -0700 (PDT)
From: Carl Lowenstein <cdl@mpl.ucsd.edu>
Message-Id: <199909080503.WAA08055 at mpl.ucsd.edu>
To: pups at minnie.cs.adfa.edu.au
Subject: Re: Diff between 11/20 and 11/45?
Sender: owner-pups at minnie.cs.adfa.edu.au
Precedence: bulk
> Date: Tue, 7 Sep 1999 14:13:30 +1000 (EST)
> From: Dave Horsfall <dave at fgh.geac.com.au>
> To: PDP Unix Preservation Society <pups at minnie.cs.adfa.edu.au>
> Subject: Re: Diff between 11/20 and 11/45?
> X-No-Archive: Yes
>
> On Tue, 7 Sep 1999, Warren Toomey wrote:
>
> > I've got a few working. cat works. ls and date run, but sort of give
> > strange outputs.
>
> What sort of strange output? My guess is that kernel-wise, date-handling
> would have changed.
It occurs to me that really early Unix used a time word in PDP-11 ticks,
not seconds. So it ran out of time a lot sooner than 2038, like maybe
only a year after it started, at 60 ticks per second, 31.5 Megaseconds per
year. This information was gleaned from a Mt.Xinu calendar from a few
years ago.
carl
Received: (from major at localhost)
by minnie.cs.adfa.edu.au (8.9.3/8.9.3) id PAA04812
for pups-liszt; Wed, 8 Sep 1999 15:28:58 +1000 (EST)
Received: from moe.2bsd.com (0 at MOE.2BSD.COM [206.139.202.200])
by minnie.cs.adfa.edu.au (8.9.3/8.9.3) with ESMTP id PAA04808
for <pups at minnie.cs.adfa.edu.au>; Wed, 8 Sep 1999 15:28:46 +1000 (EST)
Received: (from sms at localhost)
by moe.2bsd.com (8.9.0/8.9.0) id WAA17669
for pups at minnie.cs.adfa.edu.au; Tue, 7 Sep 1999 22:40:58 -0700 (PDT)
Date: Tue, 7 Sep 1999 22:40:58 -0700 (PDT)
From: "Steven M. Schultz" <sms@moe.2bsd.com>
Message-Id: <199909080540.WAA17669 at moe.2bsd.com>
To: pups at minnie.cs.adfa.edu.au
Subject: Re: Diff between 11/20 and 11/45?
Sender: owner-pups at minnie.cs.adfa.edu.au
Precedence: bulk
Howdy -
> From: Carl Lowenstein <cdl at mpl.ucsd.edu>
> Abbreviated due to fading memory over the years, but refreshed by some
> of the current discussion. The patch was zero-length but involved more
It has been a long long ('quad'? ;)) time since I first encountered
the problem.
> than the one instruction. Something similar to:
>
> MOV SP, -(SP) MOV SP, R0
> MOV (SP), R0 MOV R0, -(SP)
Ah, thank you for bringing that memory back to the front of the brain!
If R0 is available for that then yes indeed that'll do the trick very
nicely.
> on the stack. Without doing both a SRC and DST operation on SP in the
> same instruction, which is the thing that is incompatible across different
> processor hardware.
The 11/45 (and 70) behave as "expected" as do the KDJ-11 systems
(11/73, etc) so unless a person had an 11/40 (or a /20) around it
would be fairly easy to get bit by the "feature".
When it comes time for MMU "features" I know of one difference between
the KDJ-11 and the other members that had an MMU (11/44, /70, etc). Was
fun tracking it down but not something I'd want to do again ;)
Steven
Received: (from major at localhost)
by minnie.cs.adfa.edu.au (8.9.3/8.9.3) id QAA04962
for pups-liszt; Wed, 8 Sep 1999 16:17:43 +1000 (EST)
Received: from caveman.geac.com.au (caveman.geac.com.au [203.30.73.2])
by minnie.cs.adfa.edu.au (8.9.3/8.9.3) with SMTP id QAA04957
for <pups at minnie.cs.adfa.edu.au>; Wed, 8 Sep 1999 16:17:35 +1000 (EST)
Received: (qmail 10263 invoked from network); 8 Sep 1999 16:34:56 +1000
Received: from trowel.geac.com.au (203.1.26.189)
by caveman.geac.com.au with SMTP; 8 Sep 1999 16:34:56 +1000
Received: (qmail 1789 invoked from network); 8 Sep 1999 16:43:20 +1000
Received: from fgh.geac.com.au (202.6.67.163)
by trowel.geac.com.au with SMTP; 8 Sep 1999 16:43:20 +1000
Received: from localhost (dave at localhost)
by fgh.geac.com.au?r with ESMTP id QAA24887
for <pups at minnie.cs.adfa.edu.au>; Wed, 8 Sep 1999 16:29:17 +1000
X-Envelope-From: dave at horsfall.org
X-Envelope-To: <pups at minnie.cs.adfa.edu.au>
X-Authentication-Warning: fgh.geac.com.au: dave owned process doing -bs
Date: Wed, 8 Sep 1999 16:29:16 +1000 (EST)
From: Dave Horsfall <dave@fgh.geac.com.au>
X-Sender: dave at fgh
To: PDP Unix Preservation Society <pups at minnie.cs.adfa.edu.au>
Subject: Re: Diff between 11/20 and 11/45?
In-Reply-To: <199909080540.WAA17669 at moe.2bsd.com>
Message-ID: <Pine.GSO.4.10.9909081618240.19899-100000 at fgh>
X-No-Archive: Yes
X-Witty-Saying: "Tesseract - Enter at own risk"
X-Disclaimer: "Me, speak for us?"
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII
Sender: owner-pups at minnie.cs.adfa.edu.au
Precedence: bulk
On Tue, 7 Sep 1999, Steven M. Schultz wrote:
> > MOV SP, -(SP) MOV SP, R0
> > MOV (SP), R0 MOV R0, -(SP)
>
> Ah, thank you for bringing that memory back to the front of the brain!
> If R0 is available for that then yes indeed that'll do the trick very
> nicely.
Yep, I remember that now! Often thought it was odd, but it worked
on all platforms.
The convention was that R0/1 were scratch (used to return results)
and R2/3/4 had to be saved (they were the caller's first three register
variables). R5 was used as a frame pointer (?) and R6/7 you know
better as SP/PC.
> The 11/45 (and 70) behave as "expected" as do the KDJ-11 systems
> (11/73, etc) so unless a person had an 11/40 (or a /20) around it
> would be fairly easy to get bit by the "feature".
We had 40s, and used to dream of owning a 70... I learned a lot about
porting Edition 6 to the /23, /60, etc.
> When it comes time for MMU "features" I know of one difference between
> the KDJ-11 and the other members that had an MMU (11/44, /70, etc). Was
> fun tracking it down but not something I'd want to do again ;)
Do you recall the PC-board hack on the sep-ID machines that changed
the MFPI instruction to do something that was expressly prohibited?
Something about allowing a user program to access something else, for
some obscure hack or other...
--
Dave Horsfall VK2KFU dave at geac.com.au Ph: +61 2 9978-7493 Fx: +61 2 9978-7422
Geac Computers P/L (FGH Division) 2/57 Christie St, St Leonards 2065, Australia
Received: (from major at localhost)
by minnie.cs.adfa.edu.au (8.9.3/8.9.3) id UAA05921
for pups-liszt; Wed, 8 Sep 1999 20:30:43 +1000 (EST)
Received: from amber.dds.nl (amber.dds.nl [194.109.21.10])
by minnie.cs.adfa.edu.au (8.9.3/8.9.3) with ESMTP id UAA05917
for <pups at minnie.cs.adfa.edu.au>; Wed, 8 Sep 1999 20:30:34 +1000 (EST)
Received: from feline.dds.nl (feline.dds.nl [194.109.20.19])
by amber.dds.nl (8.9.3/8.9.1) with ESMTP id MAA25230
for <pups at minnie.cs.adfa.edu.au>; Wed, 8 Sep 1999 12:39:41 +0200 (MET DST)
Received: from fatima.dds.nl (hsmade at fatima.dds.nl [194.109.20.21])
by feline.dds.nl (8.9.3/8.9.1) with SMTP id MAA16806
for <pups at minnie.cs.adfa.edu.au>; Wed, 8 Sep 1999 12:41:33 +0200 (MET DST)
Date: Wed, 8 Sep 1999 12:41:32 +0200 (MET DST)
From: Wim Fournier <hsmade@dds.nl>
To: pups at minnie.cs.adfa.edu.au
Subject: Newbie question
Message-ID: <Pine.GSO.3.90.990908123352.21899B-100000 at fatima.dds.nl>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII
Sender: owner-pups at minnie.cs.adfa.edu.au
Precedence: bulk
Hi,
I am the happy owner of a pdp-11/94. I've got it from our local telecom
provider (kpn). As I am not a specialist on these machines, I would like
to ask some questions:
- My pdp won't accept mains... when I supply power it doesn't do
anything.. I've heard it could be something with the power-supply not
being closed.. but I cannot find what it is.. it's fully closed.
- I've got sdi / tu80 and an other diskcontroller... What type of disks
can I use to boot from?? (disks = floppy / tape / harddrive)
- What about the 2 connectors at the back.. 1 has 3 pins and can be
connected to the mains regulator (or something (a box for switching the
mains)) an other one has got 2 pins and no info...
- Is there some info on hardware to connect at the diverse controllers
(modem / serial??)
GreetZz
Wim Fournier
hsmade at dds.nl
^ permalink raw reply [flat|nested] 3+ messages in thread
* Diff between 11/20 and 11/45?
@ 1999-09-06 23:56 Warren Toomey
0 siblings, 0 replies; 3+ messages in thread
From: Warren Toomey @ 1999-09-06 23:56 UTC (permalink / raw)
Hi all,
Dennis Ritchie has unearthed some really old Unix a.out
executables from around 1st Edition - 2nd Edition period: see
Distributions/research/1973_stuff in the PUPS Archive.
[ Actually, I suspect his dates are a year off: they should be 1972 ]
I've printed off the 1st Ed manuals from Dennis' web page, and I'm
attempting to get my a.out emulator, Apout, to run these old binaries.
I've got a few working. cat works. ls and date run, but sort of give
strange outputs.
These executables were written for a PDP-11/20. Are there any significant
USER-MODE differences between the 11/20 and later PDP-11 models? I'm
thinking missing instructions, different addressing mode behaviour etc.
There is no source code with these binaries, so I can't use that to help
debug the emulator. I do have the following processor handbooks:
PDP-11 /20 /15 /R20 1972
PDP-11 /45 1973
PDP-11 /04 /34 /45 /55 /60 1978-79
I just thought I'd ask for pointers here before I hit them for details.
Cheers,
Warren
Received: (from major at localhost)
by minnie.cs.adfa.edu.au (8.9.3/8.9.3) id LAA27104
for pups-liszt; Tue, 7 Sep 1999 11:10:31 +1000 (EST)
Received: from henry.cs.adfa.edu.au (henry.cs.adfa.edu.au [131.236.21.158])
by minnie.cs.adfa.edu.au (8.9.3/8.9.3) with ESMTP id LAA27099
for <pups at minnie.cs.adfa.edu.au>; Tue, 7 Sep 1999 11:10:25 +1000 (EST)
Received: (from wkt at localhost)
by henry.cs.adfa.edu.au (8.9.2/8.9.3) id LAA12638
for pups at minnie.cs.adfa.edu.au; Tue, 7 Sep 1999 11:10:25 +1000 (EST)
From: Warren Toomey <wkt@cs.adfa.edu.au>
Message-Id: <199909070110.LAA12638 at henry.cs.adfa.edu.au>
Subject: KE11-A! (was Diff between 11/20 and 11/45?)
To: pups at minnie.cs.adfa.edu.au (Unix Heritage Society)
Date: Tue, 7 Sep 1999 11:10:25 +1000 (EST)
Reply-To: wkt at cs.adfa.edu.au
X-Mailer: ELM [version 2.4ME+ PL43 (25)]
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Sender: owner-pups at minnie.cs.adfa.edu.au
Precedence: bulk
Hi all,
I've just answered my own question. Reading thru the 11/20
processor handbook, I see the section on the extended arithmetic element,
KE11-A, which is ``an option to perform multiplication, division,
multiple position shifts and normalization significantly faster than
software routines''.
I also see that unit 1 lives at 777300 - 777316, and the date a.out
executable does this:
230: TRAP 15 time syscall
232: MOV #177770,@#177314
240: MOV #47432,@#177300
246: ADD #5,@#177304
254: MOV #7,@#177300
262: MOV @#177302,@#177304
270: MOV #5,@#177306
276: ADD #40622,@#177304
304: MOV @#177304,320
. . .
So it looks like I need to add KE11-A support to my emulator :-)
Cheers,
Warren
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~1999-09-08 17:00 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
1999-09-08 17:00 Diff between 11/20 and 11/45? Steven M. Schultz
-- strict thread matches above, loose matches on Subject: below --
1999-09-07 6:04 Carl Lowenstein
1999-09-06 23:56 Warren Toomey
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).