#! perl -slw
use strict;

sub bitField {
    my( $value, $offset, $size ) = @_;
    my $mask = ( ( 1<<$size) - 1 ) << $offset;
    return ( $value & $mask ) >> $offset;
}

print bitField 162, 7, 1;
print bitField 162, 4, 3;
print bitField 162, 0, 4;

__END__
P:\test>499354
1
2
2