Re^6: Will Perl Scripts written on 64 Bit Windows run fine on 32 bit as well?

I looked at the 'D' format, and it would work on machines that have 64bit integer hardware, but I need to support some 32 bit only machines. But you got me thinking, and I used some basic math to get what I need (I hope?).

The following code seems to do what I need:

   use strict;
   use warnings;
   
   my $num4g = 2 ** 32; my $grt4g = 500_000 + $num4g ;
   my $start = $num4g - 50; my $no = 0;
   while ( 1 )
   {  my $no1 = Pack( $start );
      my $result = UnPack( "$no1" );
      if ( $start != $result ) { die "not match"; }
      $start++; $no++;
      if ( $start >= $grt4g ) { print "Okay ( $no )\n"; exit; }
   }
   
   sub Pack
   {  my $input = shift;
      my $lower = $input % $num4g;
      my $upper = int ( $input / $num4g );
      return ( pack("N N", $upper, $lower ) );
   }
   
   sub UnPack
   {  my $input = shift;
      my ( $upper, $lower ) = unpack("N N", $input);
      return ( ( $upper * $num4g ) + $lower );
   }
   
   
   1;
[download]

I profiled the code and 'pack/unpack' sequence is about 2us/call. The 'Pack' is about 16us per call and the 'UnPack' is about 14us per call. Expensive, but I would then get network neutral code to 562TB, and that would be good.

Do you see anything wrong with the code?

Thank you

"Well done is better than well said." - Benjamin Franklin

Comment on Re^6: Will Perl Scripts written on 64 Bit Windows run fine on 32 bit as well? Download Code

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Re^7: Will Perl Scripts written on 64 Bit Windows run fine on 32 bit as well? by BrowserUk (Patriarch) on Dec 05, 2011 at 16:52 UTC
I looked at the 'D' format, and it would work on machines that have 64bit integer hardware, but I need to support some 32 bit only machines. First, an apology. When I said 'D' template above, I meant 'd'. (I often mix these up as so many of the other lower/upper case pairings, n is the smaller and N is the larger. But for floating point it is 'f' for the smaller and 'd' for the larger. With 'D' being a later addition that is larger still but not supported on 32- bit). By using 'd' as your template, you can portably (with restrictions) pack and unpack 'integers' upto 2*52 across the 32-bit/64-bit divide: `\perl32\bin\perl -e"$n=2;$n=2 for 1..52;$n-=20;print pack'd',$n++ for + 1..20" \| perl -nE"printf qq[%16.f\n],$_ for unpack'd', $_" 9007199254740972 9007199254740973 9007199254740974 9007199254740975 9007199254740976 9007199254740977 9007199254740978 9007199254740979 9007199254740980 9007199254740981 9007199254740982 9007199254740983 9007199254740984 9007199254740985 9007199254740986 9007199254740987 9007199254740988 9007199254740989 9007199254740990 9007199254740991` [download] Thus avoiding the need to do custom packing. Do you see anything wrong with the code?* No. The logic seems fine to me. If you decided to use this in preference to 'd', and will be un/packing long strings of values, then you might want to modify your routines to process variable numbers of values (ie. do the equivalent of 'Q*'), for efficiency. With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday' Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error. "Science is about questioning the status quo. Questioning authority". In the absence of evidence, opinion is indistinguishable from prejudice. The start of some sanity?	[reply] [d/l]
Re^8: Will Perl Scripts written on 64 Bit Windows run fine on 32 bit as well? by flexvault (Monsignor) on Dec 06, 2011 at 13:31 UTC
I tried the 'd' on both a 32bit and 64bit machine and it works great. However, when you print to disk, you find that the result is not network neutral. `Big-endian order on disk: decimal 4294967246 hex'41EFFFFFF9C00000 +' Little-endian order on disk: decimal 4294967246 hex'0000C2F9FFFFEF41 +'` [download] Note: I hope I typed the numbers correctly, since I can't cut/paste from my aixterm window to the web page. I have to save as a dos format file and then use notepad to view the file and then cut/paste. A lot of work for 2 lines :-) But let's hope the 'D' is improved to work on 32/64bit and is also network neutral. It would be the perfect answer. Thank you "Well done is better than well said." - Benjamin Franklin	[reply] [d/l]