From mboxrd@z Thu Jan 1 00:00:00 1970 From: cdl@mpl.ucsd.edu (Carl Lowenstein) Date: Mon, 6 Sep 1999 23:04:02 -0700 (PDT) Subject: Diff between 11/20 and 11/45? Message-ID: <199909070604.XAA04723@mpl.ucsd.edu> > From: Warren Toomey > 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 ; 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 ; 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 ; Wed, 8 Sep 1999 10:50:40 +1000 X-Envelope-From: dave at horsfall.org X-Envelope-To: 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 X-Sender: dave at fgh To: PDP Unix Preservation Society 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: 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 ; 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" 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 > 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 ; 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 ; 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 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 ; 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 ; Wed, 8 Sep 1999 11:15:48 +1000 X-Envelope-From: dave at horsfall.org X-Envelope-To: 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 X-Sender: dave at fgh To: PDP Unix Preservation Society Subject: Re: Diff between 11/20 and 11/45? In-Reply-To: <199909070604.XAA04723 at mpl.ucsd.edu> Message-ID: 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 ; 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 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 ; 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 ; Tue, 7 Sep 1999 14:13:31 +1000 X-Envelope-From: dave at horsfall.org X-Envelope-To: 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 X-Sender: dave at fgh To: PDP Unix Preservation Society Subject: Re: Diff between 11/20 and 11/45? In-Reply-To: <199909062356.JAA12397 at henry.cs.adfa.edu.au> Message-ID: 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 ; 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 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" > To: pups at minnie.cs.adfa.edu.au > Subject: Re: Diff between 11/20 and 11/45? > > > From: Carl Lowenstein > > > > 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 ; 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 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 > To: PDP Unix Preservation Society > 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 ; 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" 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 > 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 ; 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 ; Wed, 8 Sep 1999 16:29:17 +1000 X-Envelope-From: dave at horsfall.org X-Envelope-To: 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 X-Sender: dave at fgh To: PDP Unix Preservation Society Subject: Re: Diff between 11/20 and 11/45? In-Reply-To: <199909080540.WAA17669 at moe.2bsd.com> Message-ID: 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 ; 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 ; 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 ; Wed, 8 Sep 1999 12:41:33 +0200 (MET DST) Date: Wed, 8 Sep 1999 12:41:32 +0200 (MET DST) From: Wim Fournier To: pups at minnie.cs.adfa.edu.au Subject: Newbie question Message-ID: 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