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Bit::Vector as you might guess isn't any better...

use strict; use warnings; use Time::HiRes qw[ time ]; use Bit::Vector; my @lookup; $#lookup = 0x3ffff; $lookup[ $_ ] = [ ( $_ & 0x3f000 ) >> 12, ( $_ & 0xfc0 ) >> 6, $_ & 0x +3f ] for 0 .. 0x3ffff; my( @nxt, @mid, @bot ); $nxt[ $_ ] = ( $_ & 0x3f000 ) >> 12, $mid[ $_ ] = ( $_ & 0xfc0 ) >> 6, $bot[ $_ ] = $_ & 0x3f for 0 .. 0x3ffff; sub stuff{ # print "@_"; } our $ITERS //= 10e6; my $n = 0x80061861; my $start = time; for ( 1 .. $ITERS ) { stuff( ( $n & 0xffc00000 ) >> 18, ( $n & 0x0003f000 ) >> 12, ( $n & 0x00000fc0 ) >> 6, ( $n & 0x0000003f ) ); } printf " Shift&and took: %.12f seconds\n", ( time() - $start ) / $ITE +RS; $start = time; for ( 1 .. $ITERS ) { stuff( $n >> 18, @{ $lookup[ $n & 0x3ffff ] } ); } printf " Lookup took: %.12f seconds\n", ( time() - $start ) / $ITE +RS; $start = time; for ( 1 .. $ITERS ) { my $i = $n & 0x3ffff; stuff( $n >> 18, $nxt[ $i ], $mid[ $i ], $bot[ $i ] ); } printf " Lookup2 took: %.12f seconds\n", ( time() - $start ) / $ITE +RS; $start = time; for ( 1 .. $ITERS ) { stuff( unpack 'vccc', join'',map{ pack'b*', $_ } unpack 'a14a6a6a6 +', unpack 'B32', pack 'N', $n ); } printf " (un)pack took: %.12f seconds\n", ( time() - $start ) / $ITE +RS; $n="$n"; my $vector; $start = time; for (1 .. $ITERS ) { $vector = Bit::Vector->new_Hex(32, $n); stuff($vector->Chunk_Read(14, 18), $vector->Chunk_Read( 6, 12), $vector->Chunk_Read( 6, 6), $vector->Chunk_Read( 6, 0) ); } printf "Bit::Vector took: %.12f seconds\n", ( time() - $start ) / $ITE +RS; __END__ C:\test>perl bv.pl Shift&and took: 0.000000551174 seconds Lookup took: 0.000000272709 seconds Lookup2 took: 0.000000335823 seconds (un)pack took: 0.000003393702 seconds Bit::Vector took: 0.000005372898 seconds

In reply to Re^3: Efficient bit-twiddling in Perl. by ggoebel
in thread Efficient bit-twiddling in Perl. by BrowserUk

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