- $b = substr($old_bsr,0,$o) . reverse $v . substr($old_bsr,$o+length($v));
+ #$b = substr($old_bsr,0,$o) . reverse $v . substr($old_bsr,$o+length($v));
+ $b = ( "0" x $o ) . reverse $v . ( "0" x ( length($old_bsr) - $o - length($v) ) );
+warn "XXX",length($old_bsr), " == ",length($b);
+ $old_bsr = "0" x length($old_bsr);