sub decode_d2b {
my $lb = $_[1];
my $hb = $_[0];
my $z = hex($hb)*256 + hex($lb);
if (($z & 0x8000) == 0x8000) {
                my $y = -((~hex($hb) & 255) + ((~hex($lb) & 255) + 1)/256);
				return $y;
        }
        else {
my $y = hex($hb) + ((hex($lb))/256);
return $y;
}
return;
}