print unpack 'C*', pack '(B8)*', map{ 
       substr '00000000'.$_, -8 
} unpack 'A1A3A4',unpack 'B*',pack 'C', 162;;

1 2 2

##</code><code>##

## pack 162 into an 8-bit binary value (a char).
pack 'C', 162       

## unpack that into it's bits, (asciized binary bitstring).
unpack 'B*',        

## split that into the 3 fields. ('1','010', '0010' ).
unpack 'A1A3A4',    

## Pad each to the smallest size (8 bits) that Perl can deal with numerically.
map{ substr '00000000'.$_, -8 }
                    
## Pack them back up to binary values (chars).
pack '(B8)*',       

## And unpack them back to numeric values.
unpack 'C*',        

## and convert those to ascii-decimal for display
print               

##</code><code>##

#! 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
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2
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