[TUHS] can someone help about the pdp11/34 boot ? :(

[Carl Lowenstein]

On 8/30/05, asbesto <asbesto at freaknet.org> wrote:
> 
> 
> Hi,
> 
> is anyone here that can help us booting the pdp11/34 ? :
> 
> the boot loader hangs at 001012. can someone help understand
> why?
> 
> we haven't any bus error, and we have no prompt at serial
> terminal pressing "ctrl-boot"
> 
> this is the boot code, found in "E-10 Loading Software Bootstrap":
> 
> location contents pseudo-source code
> 001000 012701 mov #174400, r1
> 001002 174400
> 001004 012761 mov #13, 4(r1)
> 001006 000013
> 001010 000004
> 001012 012711 mov #4, @r1
> 001014 000004
> 001016 105711 tstb @r1
> 001020 100376 bpl .-2
> 001022 005061 clr 2(r1)
> 001024 000002
> 001026 005061 clr 4(r1)
> 001030 000004
> 001032 012761 mov #-400, 6(r1)
> 001034 177400
> 001036 000006
> 001040 012711 mov #14, @r1
> 001042 000014
> 001044 105711 tstb @r1
> 001046 100376 bpl .-2
> 001050 005007 clr pc
> 
> starting it, the display show "1012", i think this mean that
> he stop at address 001012. why?


The display shows the next address to be executed. When the processor halts, 
what are the
actual contents of locations 1000-1010? Are they what you keyed in, or has 
this memory been
over-written? 

This looks like code for a RL01/RL02.
Is the bus address of its control registers the normal 174400 - 177406?

If you replace the last instruction CLR PC (5007) with HLT (0000) does the 
processor
get there? This should happen regardless of what is read from the disk, 
because the
code from the disk is not executed.

You can find a lot of small key-in test programs at
< http://www.dunnington.u-net.com/public/ODT/SourceCode/ >

carl
-- 
carl lowenstein marine physical lab u.c. san diego
clowenst at ucsd.edu
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