[Simh] XXDP V2.2 problems.

[Johnny Billquist]

Well, the difference between the 11/23 and 11/23+ is actually that the 
former only supports 18-bit addressing. The 23+ added the 22-bit 
addressing. Although, actually finding real 11/23 CPUs are unusual. Most 
were upgraded to 23+, or were actually 23+ from the start.
(That is, unless I have a bit error somewhere in my memory.)

When XXDP V2.2 is slightly old. Why are you running that, and not 2.5? 
Also, unfortunately DEC had a tendency to break XXDP on older machines 
when they made changes. XXDP was rather poorly maintained.

When you are booting XXDP on your 11/23, it halts, but when you continue 
it says that it was unable to boot XXDP-XM, and instead boots XXDP-SM. 
So obviously it tries -XM by default, so I'm unsure why you think that 
it's booting -SM at any time normally.

And when -SM boots up it reports 28KW of memory, which seems consistent 
with a small memory machine, and that -XM would not be able to boot. So, 
when you are booting XXDP on your 11/44 or 11/23+, are you really sure 
you only have 64Kbyte memory configured? I would not expect -XM to boot 
then either.

	Johnny

On 2015-12-28 16:00, Mattis Lind wrote:
> I have some troubles running a known working XXDP V2.2 image in SimH on
> a 11/23 (without +), 11/03, 11/04, 11/05 and 11/20.
>
> I have tested this on a PDP-11/44 and a PDP-11/23+ CPU and it works
> fine. Testing the same image in SimH on 11/23+ and 11/44 config with
> 64kbyte memory starts the XXDP fine.
>
> https://dl.dropboxusercontent.com/u/96935524/xxdp.dsk
>
>
> Now I have to be honest. I am not entirely sure which CPU configs should
> be able to run XXDP V2.2 (Small Monitor).
>
> But I basically thought that switching to 11/23 (without plus) should
> work fine since it is very similar to the plus. Just removing the two
> SLUs and the Boot ROMs would make it identical as far as I can see it.
>
> But it doesn't start.
>
> sim> b rq0
>
>
> HALT instruction, PC: 000104 (JMP SP)
>
> Doing a continue actually makes it to boot:
>
> sim> c
>
> NOT ENOUGH MEMORY TO BOOT XXDP-XM
>
>
>
> BOOTING UP XXDP-SM SMALL MONITOR
>
>
>
> XXDP-SM SMALL MONITOR - XXDP V2.2
> REVISION: C0
> BOOTED FROM DU0
> 28KW OF MEMORY
> NON-UNIBUS SYSTEM
>
> RESTART ADDR: 152010
> TYPE "H" FOR HELP
>
> .
>
> But it is not entirely happy since the very simple GKAAA0 cpu test that
> runs fine in 11/23+ mode fails.
>
> .R GKAAA0
> GKAAA0.BIC
>
> HALT instruction, PC: 000104 (JMP SP)
> sim>
>
> I know that SimH is not supposed to be able to run the diags but what is
> the difference on a SimH level between 11/23 and 11/23+ that causes one
> to run and the other not?
>
> Then I tested some other CPUs:
>
> 11/34, 11/40, 11/44, 11/45, 11/60, 11/70, 11/73, 11/83, 11/84, 11/93
>
> The all can start XXDP V2.2 (SM) and run GKAAA0 fine.
>
> But
>
> 11/03 and 11/23 give me the halt. In the 11/03 case it is not possible
> to do a continue.
>
> Testing 11/04, 11/05 and 11/20 all give the same result. It never boots
> but gets stuck in some loop where it seems to poll the console.
>
> Step expired, PC: 150674 (BPL 150750)
> sim> s
>
> Step expired, PC: 150750 (MOV (SP)+,R1)
> sim> s
>
> Step expired, PC: 150752 (RTS PC)
> sim> s
>
> Step expired, PC: 151006 (TST R0)
> sim> s
>
> Step expired, PC: 151010 (BEQ 151002)
> sim> s
>
> Step expired, PC: 151002 (JSR PC,150664)
> sim> s
>
> Step expired, PC: 150664 (CLR R0)
> sim> s
>
> Step expired, PC: 150666 (MOV R1,-(SP))
> sim> s
>
> Step expired, PC: 150670 (TSTB @#177560)
> sim> s
>
> Step expired, PC: 150674 (BPL 150750)
> sim> s
>
>
> SimH is built from head:
>
> sim> sh ver
> PDP-11 simulator V4.0-0 Beta
> Simulator Framework Capabilities:
> 32b data
> 32b addresses
> Ethernet Packet transports:PCAP:NAT:UDP
> Idle/Throttling support is available
> Virtual Hard Disk (VHD) support
> Asynchronous I/O support
> FrontPanel API Version 1
> Host Platform:
> Compiler: GCC 4.2.1 Compatible Apple LLVM 5.0 (clang-500.2.76)
> Simulator Compiled: Dec 27 2015 at 17:51:17
> Memory Access: Little Endian
> Memory Pointer Size: 64 bits
> Large File (>2GB) support
> RegEx support for EXPECT commands
> OS clock resolution: 1ms
> Time taken by msleep(1): 2ms
> OS: Darwin localhost 12.5.0 Darwin Kernel Version 12.5.0: Sun Sep 29
> 13:33:47 PDT 2013; root:xnu-2050.48.12~1/RELEASE_X86_64 x86_64
>
>          git commit id: ea4d9a16
>
> Tested SimH 3.9 and it does the same
>
> 11/04, 11/05 and 11/20 all lack MMU if this has to do with it. But 11/03
> also lack MMU and is not behaving the same, although not booting. The
> 11/23 has the MMU but is still not booting while the almost identical
> 11/23+ boots just fine.
>
> Well. If someone can help me sort this out I am would be happy. My next
> step is to try to boot the same image on a real 11/04, 11/03 and a 11/23
> (without +) to see if that works. Just need to toggle in that long
> bootstrap.
>
> /Mattis
>
>
>
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>

-- 
Johnny Billquist                  || "I'm on a bus
                                   ||  on a psychedelic trip
email: bqt at softjar.se             ||  Reading murder books
pdp is alive!                     ||  tryin' to stay hip" - B. Idol