[LMH]Re: LispM-Hackers digest, Vol 1 #190 - 1 msg

[Nyef]

On Sat, 12 Jul 2003, Steve Krueger wrote:

> Al,
> 
> It looks to me like you can find the nupi descriptor format in 
> ucode/lroy-qdev.lisp.  Its fields are there in a defenum:
> 
> (DefEnum NUPI-Normal-Descriptor (Q-CORRESPONDING-VARIABLE-LISTS
>                   System-Constant-Lists)
>     (%NUPI-Interrupt-Link
>      %NUPI-Interrupt-Information
>      %NUPI-Control-Space-Address
>      %NUPI-Information
>      %NUPI-Queue-Base)
>   )
> 
> I hope that helps.
> 
>     -Steve

Or SSDN2, section 4.4.1, with some explanatory text.

http://www.dridus.com/~nyef/ssdn2/sect04.html#sect_4_4_1


For the record, I tracked the problem I was having with the device 
descriptor block down to a problem with the ASH instruction emulation 
causing MAKE-ARRAY to not create a displaced array, instead allocating all 
the space itself. Oops. That might not have been the only part of the 
problem, but it was the largest contributing cause.

The problem with a DTP-Array pointing to a DTP-Array word was a problem 
with the ARRAY-LENGTH instruction causing INITIALIZE-ARRAY to 
mis-calculate the start and length for a %BLT-TYPED operation.

The problem with the DPMT turned out to be an address with the high bit 
set, due to a problem with... I forget what it was with, but it involved 
shifting a FIXNUM right 1 bit and accidentally getting the low bit of the 
tag into the high bit of the resultant address. I improved the diagnostic 
messages for this, though, based on what I saw in the band save code.

So far, every time this week that I've asked for help from the list, I've 
been completely off-base as to what the causes were. I hope this was just 
an off week. Alternatively, given how much progress was made, maybe I 
should hope that things continue at about the same rate?


Does anyone have any ideas for what to do about emulating DTP-U-Entry 
"functions"? I'm going to take a stab at getting the U-Entry for LIST 
working tomorrow...

---------------------------
All programming can be viewed as an exercise.
---------------------------
Alastair Bridgewater
e-mail: nyef@softhome.net