VAX-11/730 and Emulex UC17 woes

Mike Ross tmfdmike at gmail.com
Tue May 24 18:07:04 CDT 2016


On Wed, May 25, 2016 at 11:03 AM, Josh Dersch
<JoshD at livingcomputermuseum.org> wrote:

*another snip*

> Thanks.  Glen sent me his dump and I compared with mine.  I have the same three differences:
>
> D 000002A0 01200880   // 0100F308
> D 000002BC 0014688F   // FFF4688F
> D 000002C0 65B45520   // 65B45500
>
> (commented values are the ones that differ on my machine).
>
> This changes the code as below:
>
> -> 298:    MOVL #80000002,@#F30808   (was: 298:    MOVL #80000002,@#20088008)
> 2A3:    NOP
> 2A4:    MTPR #1F,#12
> 2A7:    MOVAL 400,R1
> 2AE:    MOVL #200,R2
> 2B5:    MOVL #0,(R1)+
> 2B8:    SOBGTR R2,2B5
> -> 2BB:    MOVL #FFF468,R5   (was 2BB:    MOVL #20001468,R5)
>
> I suspect these values are changed "on the fly" based on the machine type punched into the SA register as the last step before the "S 80" command; in particular, the source address for the MOVL instruction at 2BB now makes more sense, corresponding to a value in the UBA register set for the UC17.
>
> However, F30808 doesn't make sense as the destination argument address for the MOVL at 298.  This looks like a map register for an 11/750 (as documented in the UC17 manual as being at F30800/F30804) and I wondered if it should be similar to the value for the 11/730 (F26800/F26804).
>
> So I changed the instruction at 298 to:
>
> MOVL #80000002,@#F26808
>
> (which corresponds to a change in the value at 2A0 to 0100F268)
>
> On the VAX-11/730 and did an "S 80" and lo and behold, it works!


Ooooh! I'll have to try that! Thanks. Great sleuthing!


Mike

http://www.corestore.org
'No greater love hath a man than he lay down his life for his brother.
Not for millions, not for glory, not for fame.
For one person, in the dark, where no one will ever know or see.'


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