How about this?

#!/usr/bin/perl

my $s = "DA39A3EE5E6B4B0D3255BFEF95601890AFD80709";
my $mask1 = "FFFF804020100804020100804020100804000102";

my $result = bin2hex(hex2bin($s) & hex2bin($mask1));
print $result,"\n";

sub hex2bin
{
  my($s)=@_;
  $s =~ tr/0-9A-F/\x00-\x09\x0A-0x0F/;
  $s;
}

sub bin2hex
{
  my($s)=@_;
  $s =~ tr/\x00-\x09\x0A-0x0F/0-9A-F/;
  $s;
}
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