VAX-11/730 and Emulex UC17 woes

[Mike Ross]

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

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