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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 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.)
>>> 
>>> Robert, you do realize that anything you are going to print will take 
>>> billions of cycles for every second the printer needs to actually print 
>>> the pages?
>> 
>> Really? ROFL...
>> 
>> Of course I do realise that once I/O is added, all bets are off. But as 
>> I've mentioned in another reply you may already have seen, sometimes
>> others approach a problem from a completely different angle, with stunning 
>> results.
> 
> OK, here's the most obvious (?) one:
> 
> Create a function for each of these lists, put them all on an array and call 
> them in order with the current item:
> 
> Each time a list has been completed, the corresponding function pointer 
> removes itself from the array of functions to be called.

Great minds (OK, one very great mind and my rather smaller one) seem to think 
the same, I'm actually using a similar approach in the follow-up program that 
converts the output of "LIFT" to RTF format:

@02:
   mov   eax, _s
   lea   eax, [eax * 4 + offset @03]
   jmp   dword ptr [eax]

   align 4

@03:
   dd    offset @04  //  0 - Trip                    ->  0   s ->  1
   dd    offset @05  //  1 - Trip fall through       ->  2
   dd    offset @06  //  2 - Type                    ->  2   s ->  3
   dd    offset @07  //  3 - Type fall through       ->  4
   dd    offset @08  //  4 - Cnty                    ->  4   s ->  5
   dd    offset @09  //  5 - Cnty fall through       ->  6
   dd    offset @10  //  6 - Nat                     ->  6   s ->  7
   dd    offset @11  //  7 - Nat  fall through       ->  8
   dd    offset @14  //  8 - Naco / Cnty #I/#E       ->  8   s ->  9
   dd    offset @18  //  9 - Cnty #I/#E fall through -> 10
   dd    offset @20  // 10 - Year                    -> 10   s -> 11
   dd    offset @21  // 11 - Year fall through       -> 12
   dd    offset @22  // 12 - V! tables               -> 12   s -> 13
   nop
   nop
   nop
   nop

@04:

Sadly, this approach is not (entirely) possible here, because the Country top-10 
tables are "incomplete", I've hitched through Bulgaria, Slovakia, and Andorra, 
but I've never hitched in those countries.

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

More later,

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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