#!/usr/bin/perl -wl
use strict;
use Data::Dumper;
my $N = 4;
my $size = 32;
my $arr = [[1, 2],
[3, 4],
[5, 6],
[7, 8]];
my @C;
foreach my $m (0..2**$N - 1) {
my $vec = "";
vec($vec, 0, $size) = $m;
my @bits = split(//, unpack("B*", $vec));
splice(@bits, 0, $size - $N);
# so @bits now contains the binary expansion of $m
# with exactly $N bits, as you can verify by uncommenting
# print join "::", @bits;
$C[ $m ] = 1;
# now we multiply the $N terms $arr->[i][j]
# where j is the i-th bit in the binary expansion of $m
$C[ $m ] *= $arr->[ $_ ][ $bits[$_] ] for 0..$N-1;
}
print Dumper \@C;