Re: Efficient bit-twiddling in Perl.

[dave_the_m]

Note that the code you've got is already fairly efficient. Consider the following:

my $n = 0x80061861;
for (1..10_000_000) {
    my $top14 = ( $n & 0xfffc0000 ) >> 18;
    my $nxt6  = ( $n & 0x0003f000 ) >> 12;
    my $mid6  = ( $n & 0x00000fc0 ) >>  6;
    my $bot6  = ( $n & 0x0000003f );

    # or replace the four lines above with:
    #my ($top14, $nxt6, $mid6, $bot6) = (1,1,1,1);
}

Running as-is on my system takes 3.1s; using just the last line (which represents a baseline of creating, setting and freeing those four lexical vars), takes 1.9s. So any savings you make are likely to be less than that.

Dave.

[BrowserUk]

Se Re^2: Efficient bit-twiddling in Perl. for my starting position.