Re: PDP-11/05 Fault?
-- Original Message -- From: "Jerry Weiss via cctalk" To: "Paul Koning" ; "General Discussion: On-Topic and Off-Topic Posts" ; "Nigel Williams" Sent: Thursday, 30 Sep, 2021 At 15:08 Subject: Re: PDP-11/05 Fault? On 9/30/21 8:12 AM, Paul Koning via cctalk wrote: On Sep 30, 2021, at 1:02 AM, Nigel Williams wrote: On Thu, Sep 30, 2021 at 10:49 AM Paul Koning via cctalk wrote: I see that the PDP-11 architecture handbook doesn't seem to be on Bitsavers... Do you mean this handbook? http://wwcm.synology.me/pdf/EB-23657-18%20PDP-11%20Architecture%20Handbook.pdf <http://wwcm.synology.me/pdf/EB-23657-18%20PDP-11%20Architecture%20Handbook.pdf> ORDER CODE: EB-23657-18 (from here: http://wwcm.synology.me/scanned.html <http://wwcm.synology.me/scanned.html> ) Yes, that's the one. Excellent reference, it's the only place where I've seen that entire large tables (52 entries) of model differences. paul The same table is also in EK-DCJ11-UG-PRE_J11ug_Oct83.pdf. I find the latter just a bit easier to read. Jerry That book multiplies like rabbits though. I swear, any time i buy any new PDP-11 literature, i somehow end up with another copy. They're not that rare (or maybe i'm just lucky) Josh
Re: PDP-11/05 Fault?
On 9/30/21 8:12 AM, Paul Koning via cctalk wrote: On Sep 30, 2021, at 1:02 AM, Nigel Williams wrote: On Thu, Sep 30, 2021 at 10:49 AM Paul Koning via cctalk wrote: I see that the PDP-11 architecture handbook doesn't seem to be on Bitsavers... Do you mean this handbook? http://wwcm.synology.me/pdf/EB-23657-18%20PDP-11%20Architecture%20Handbook.pdf ORDER CODE: EB-23657-18 (from here: http://wwcm.synology.me/scanned.html) Yes, that's the one. Excellent reference, it's the only place where I've seen that entire large tables (52 entries) of model differences. paul The same table is also in EK-DCJ11-UG-PRE_J11ug_Oct83.pdf. I find the latter just a bit easier to read. Jerry
Re: PDP-11/05 Fault?
> On Sep 30, 2021, at 1:02 AM, Nigel Williams > wrote: > > On Thu, Sep 30, 2021 at 10:49 AM Paul Koning via cctalk > wrote: >> I see that the PDP-11 architecture handbook doesn't seem to be on >> Bitsavers... > > Do you mean this handbook? > > http://wwcm.synology.me/pdf/EB-23657-18%20PDP-11%20Architecture%20Handbook.pdf > > ORDER CODE: EB-23657-18 > > (from here: http://wwcm.synology.me/scanned.html) Yes, that's the one. Excellent reference, it's the only place where I've seen that entire large tables (52 entries) of model differences. paul
Re: PDP-11/05 Fault?
On Thu, Sep 30, 2021 at 10:49 AM Paul Koning via cctalk wrote: > I see that the PDP-11 architecture handbook doesn't seem to be on Bitsavers... Do you mean this handbook? http://wwcm.synology.me/pdf/EB-23657-18%20PDP-11%20Architecture%20Handbook.pdf ORDER CODE: EB-23657-18 (from here: http://wwcm.synology.me/scanned.html)
Re: PDP-11/05 Fault?
On 9/29/2021 6:31 PM, Matt Burke via cctalk wrote: I've been restoring a PDP-11/05 recently and after replacing several faulty ICs I have it mostly working. I've run into a bit of a problem whilst running MAINDEC-11-D0NB (T14 TRAP TEST) though. The failing instruction sequence is: 7200: MOV #6340,R0 7204: MOV R0,(R0)+ 7206: CMP 6340,#6342 7214: BEQ 7220 7216: HALT This halts at 7216 with: R0 = 6342 6340 = 6340 I tried this same set of instructions on a PDP-11/84 and also on Simh and the result is: R0 = 6342 6340 = 6342 which is what the diagnostic seems to expect. Firstly, I think this is a documented processor difference. My PDP-11/05S , 11/10S manual, DEC-11-H05SS-B-D, in table 4-8, programming differences reads: OPR %R,(R)+ 11/20: Contents of R are incremented by 2 *before* being used as the source operand. 11/05 & 11/10: Initial contents of R are used as the source operand 11/35 & 11/40: (Same as 11/20) So the halt would be expected on an 11/05. Secondly, I have an original DEC listing of D0NB. On it I have a written note (by me) "Bugs according to (UW Madison) ECE". But there is no notation of that those bugs might be. The source in my listing reads essentially the same as what you have written (comments abbreviated to fit on my lines): 7200 012700 006340 MOV#K11,%0 ; SRC and DST BOTH R0 7204 010020 MOV%0,(0)+ ; SRC No Mem Reference 7206 026727 177126 006342 CMPK11,+#K11+2 ; Dest Is Mem Reference 7214 001401 BEQ.+4 7216 00 HLT; Failed %(0),(0)+ 7220 010700 SCOPE JRJ
Re: PDP-11/05 Fault?
> On Sep 29, 2021, at 8:21 PM, Matt Burke wrote: > > On 30/09/2021 01:06, Paul Koning wrote: >> Either the diagnostic has a major bug, or you're running it on a machine it >> doesn't support, or there is a setup to tell it the difference which you >> missed. >> >> What you're seeing is the very first entry in the table "PDP-11 family >> differences", appendix B of the PDP-11 architecture handbook. It is the >> famous pattern that the assembler rejects with a Z (machine dependency >> alert) error code. >> >> This particular pattern produces 6342 only on 11/23, 11/20, 11/35, 11/70, >> J-11, and T-11. On all others, including the 11/05 and the PDP-11 emulation >> in the VAX, it produces 6340 as you observed. >> >> paul >> > > Thanks, Paul. The MAINDEC-11-D0NB diagnostic is meant for the PDP-11/20 > according to the listing though the same goes for many other diagnostics > which are also applicable to the PDP-11/05. I guess this one is the > exception. There is a newer version MAINDEC-11-D0NC but I can't find a > listing for that one. Perhaps it has a switch register setting to handle > the difference. Perhaps it was written just for the 11/20 when that was the only model. You mentioned it's a T14 test -- that is actually one that probably cares about the model a lot for another reason -- differences 10 and 11. In the 11/05 and 11/20 (and VAX), an RTI with T set in the saved PSW traps after one instruction (i.e., you get single stepping). In all others, the T14 trap occurs immediately and you have to use the RTT instruction to get the single step action. 11/05 and 11/20 don't have RTT. The debugger (ODT) in an early version used the instruction you ran into as a way to see whether to use RTI or RTT for single step. Of course, that doesn't work with the other machines that work that way, and presumably it was changed later. It could try RTT with a T10 vector set to catch the illegal instruction trap an 11/05 would give it, for example. I see that the PDP-11 architecture handbook doesn't seem to be on Bitsavers... paul
Re: PDP-11/05 Fault?
On 30/09/2021 01:06, Paul Koning wrote: > Either the diagnostic has a major bug, or you're running it on a machine it > doesn't support, or there is a setup to tell it the difference which you > missed. > > What you're seeing is the very first entry in the table "PDP-11 family > differences", appendix B of the PDP-11 architecture handbook. It is the > famous pattern that the assembler rejects with a Z (machine dependency alert) > error code. > > This particular pattern produces 6342 only on 11/23, 11/20, 11/35, 11/70, > J-11, and T-11. On all others, including the 11/05 and the PDP-11 emulation > in the VAX, it produces 6340 as you observed. > > paul > Thanks, Paul. The MAINDEC-11-D0NB diagnostic is meant for the PDP-11/20 according to the listing though the same goes for many other diagnostics which are also applicable to the PDP-11/05. I guess this one is the exception. There is a newer version MAINDEC-11-D0NC but I can't find a listing for that one. Perhaps it has a switch register setting to handle the difference. I did wonder if this might be a model specific issue and I did various searches online but didn't find the right info. Thanks for the pointer. At least I know it's not a fault that needs debugging now. Regards, Matt
Re: PDP-11/05 Fault?
> On Sep 29, 2021, at 7:31 PM, Matt Burke via cctalk > wrote: > > > I've been restoring a PDP-11/05 recently and after replacing several > faulty ICs I have it mostly working. I've run into a bit of a problem > whilst running MAINDEC-11-D0NB (T14 TRAP TEST) though. > > The failing instruction sequence is: > > 7200: MOV #6340,R0 > 7204: MOV R0,(R0)+ > 7206: CMP 6340,#6342 > 7214: BEQ 7220 > 7216: HALT > > This halts at 7216 with: > R0 = 6342 > 6340 = 6340 > > I tried this same set of instructions on a PDP-11/84 and also on Simh > and the result is: > R0 = 6342 > 6340 = 6342 > > which is what the diagnostic seems to expect. Either the diagnostic has a major bug, or you're running it on a machine it doesn't support, or there is a setup to tell it the difference which you missed. What you're seeing is the very first entry in the table "PDP-11 family differences", appendix B of the PDP-11 architecture handbook. It is the famous pattern that the assembler rejects with a Z (machine dependency alert) error code. This particular pattern produces 6342 only on 11/23, 11/20, 11/35, 11/70, J-11, and T-11. On all others, including the 11/05 and the PDP-11 emulation in the VAX, it produces 6340 as you observed. paul
