comment on

I need to break unsigned 32-bit values into 4 parts: (from the msb) 14-bits, 6-bits, 6-bits, 6-bits; (using perl rather than I::C or XS). That can be done as follows:

#! perl -slw
use strict;

my $n = 0x80061861;
my $top14 = ( $n & 0xfffc0000 ) >> 18;
my $nxt6  = ( $n & 0x0003f000 ) >> 12;
my $mid6  = ( $n & 0x00000fc0 ) >>  6;
my $bot6  = ( $n & 0x0000003f );

print "$n => $top14 : $nxt6 : $mid6 : $bot6";
__END__
C:\test>bit
2147883105 => 8193 : 33 : 33 : 33
[download]

But I need to do this millions of times, so I'm looking to see if there is a more efficient way? (I don't care if I get 4 separate variables or an array with 4 values.)

Note: This is for me; no one else. Elegance, readability and maintainability are simply not considerations here. Just speed.

Any suggestions?

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In reply to Efficient bit-twiddling in Perl. by BrowserUk

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