strange number corruption on pdp11/34

Don North north at alum.mit.edu
Tue Jan 27 17:38:05 CST 2015


On 1/27/2015 3:13 PM, Johnny Billquist wrote:
> On 2015-01-28 00:05, Noel Chiappa wrote:
>>      > From: Johnny Billquist
>>
>>      > If it comes as far as booting RSX as well as XXDP, there can't be
>>      > anything seriously wrong with the CPU...
>>
>> Yeah, I see your point, but why all the zeros, then? That's what I could't
>> work out.
>>
>> Anyway, it should be really easy to make sure e.g. ASH, MUL and DIV are
>> working; it's vaguely plausible that one of them is broken. (Unix V6, I think,
>> might even boot even if MUL was broken. I know the bootstrap uses DIV, to
>> calculate the cylinder in the disk driver.) If not, cross that off the list,
>> and try the next thing... Which is?
>
> Is noone paying attention to the fact (and my previous comment) about using 0 
> for CSR and vector???
>
>     Johnny
>

No, but it is likely those values are OK, but are being printed as ZERO the same 
way all the other numbers are ...


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