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Re: Speeding up code - am I missing something?

Cross-posted to 4 groups.

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On 2018-08-17 19:20, Robert Prins wrote:
> On 2018-08-17 06:49, Terje Mathisen wrote:
>> Robert Prins wrote:
>>> On 2018-08-16 16:02, Terje Mathisen wrote:
>>>> (newsgroups limited to just clax86, my server does not allow indiscriminate 
>>>> cross-posting.)

<snip>

> Obviously I could cater for this, but while we've got this discussion going, 
> I've decided to try filling the entire top-N in the "caching" code, where I end 
> up going to nearly the bottom, entry 4,300 of (currently) 4,310 rides, anyway. A 
> quick test using the old PL/I version, where I can use a compiler option that 
> tells me how many times each statement is executed, tells me that the executed 
> statement count is reduced by more than 90% when I use this approach for the 
> Top-10s of trips. ;)
> 
> Only unpleasant side issue is the fact that I'm using 3-D arrays,
> 
> dcl 1 t10_trip(trip_total.trip) ctl,
>        2 tr_ix(3)        fixed bin (31) init ((3)0),
>        2 tr_ktv(3, 10)   ptr;
> 
> with
> 
> #j = t10_trip(lift_list.trip).tr_ix(1) + 1;
> if #j <= hbound(tr_ktv, 3) then
>    t10_trip(lift_list.trip).tr_ktv(1, #j) = lift_ptr;
> 
> t10_trip(lift_list.trip).tr_ix(1) = #j;
> 
> to fill the top-10 slots, and worse for the Type/Country/Nat tables where I
> have to do a lookup of the index. (Which leads to the question, is there a
> way using all the new whiter than white x86 instructions to fast match a
> 4-byte value in an array of up to (potentially) 234 values? I'm now using the
> "vpcmpistri" (see another tread) to find CR's in the buffer (and don't
> understand why I require a VPXOR or set them to 0x00), and similar code would
> probably faster than a discretely coded version of CMPSD...)
> 
> which won't result in pretty code using Virtual Pascal. 

Needlessly to say, the VP generated code is ugly as (insert your favourite 
expletive)!

> Need to check what Enterprise PL/I generates, but even here, based on past
> experience, I'm somewhat pessimistic.

And this code seems to be pretty good using Enterprise PLI V4.5.0. Would need 
use another system to see what Enterprise PL/I V5.2.2 generates.

Running time with VP generated code is around 5% less than old (find only 
top-of-sublist) code. ;) Now just have to hack it into something more palatable.

One feature sadly missing from Pascal is the fact that PL/I allows you to use 
'*' as array extents in a called proc, and the (hidden) descriptors that are 
also passed to it allow you to call the same proc with

dcl 1 t10_summ(1) ctl,
       2 su_ix(3)        fixed bin (31),
       2 su_ktv(3,50)    ptr;

dcl 1 t10_trip(trip_total.trip) ctl,
       2 tr_ix(3)        fixed bin (31),
       2 tr_ktv(3,10)    ptr;

dcl 1 t10_cnty(0:lift_work.#cnty) ctl,
       2 co_ix(3)        fixed bin (31),
       2 co_ktv(3,10)    ptr;

dcl 1 t10_year(year_top -> year_list.year:
                year_end -> year_list.year) ctl,
       2 yr_ix(3)        fixed bin (31) init ((3)0),
       2 yr_ktv(3,10)    ptr;

and a set of builtin functions (lbound and hbound) can be used to retrieve the 
low and high bounds of the arrays. ;) It's a bit more convoluted to do this with 
Pascal...

Robert
-- 
Robert AH Prins
robert(a)prino(d)org

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Thread

Speeding up code - am I missing something? Robert Prins <robert@nospicedham.prino.org> - 2018-08-15 21:37 +0000
  Re: Speeding up code - am I missing something? Peter Flass <peter_flass@nospicedham.yahoo.com> - 2018-08-15 17:52 -0400
    Re: Speeding up code - am I missing something? Robert Prins <robert@nospicedham.prino.org> - 2018-08-16 19:51 +0000
  Re: Speeding up code - am I missing something? Robert Prins <robert@nospicedham.prino.org> - 2018-08-16 20:38 +0000
    Re: Speeding up code - am I missing something? Robert Prins <robert@nospicedham.prino.org> - 2018-08-17 19:20 +0000
      Re: Speeding up code - am I missing something? Robert Prins <robert@nospicedham.prino.org> - 2018-08-23 17:21 +0000
        Re: Speeding up code - am I missing something? Peter Flass <peter_flass@nospicedham.yahoo.com> - 2018-08-23 11:47 -0400
        Re: Speeding up code - am I missing something? rugxulo@gmail.com - 2018-08-31 09:47 -0700
          Re: Speeding up code - am I missing something? Robert Prins <robert@prino.org> - 2018-09-01 10:08 +0000
            Re: Speeding up code - am I missing something? Marco van de Voort <marcov@toad.stack.nl> - 2018-09-01 11:20 +0000
            Re: Speeding up code - am I missing something? rugxulo@gmail.com - 2018-09-03 17:32 -0700

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