Re: ✘nmea.lasttag

[Michael J. Tubby B.Sc. MIET]

    Yo Gary!
    
    If you google for "uint128_t processor support" there's quite a lot
    of noise about either (a) processors or (b) versions of gcc for
    processors that don't support a 128-bit integer type.
    
    I'm not exactly sure what you need to achieve but it its bit
    fields/flags and the like you're probably safer using a list (array)
    of 32-bit or 64-bit integers.
    
    
    Mike

On 07/04/2020 23:50, Gary E. Miller wrote:

> Yo All!
>
> Ugh.  I found the problem with arm32 and test/daemon/bundg_zeus_9.log.
> driver_nmea0183 now has more cycle enders than there are bits in a uint64_t.
>
> Coverity spotted the bug as soon as the new NMEA sentences were added:
>
>
> _____________________________________________________________________
> *** CID 292260:  Integer handling issues  (BAD_SHIFT)
> /driver_nmea0183.c: 3601 in nmea_parse()
> 3595                  (unsigned long long)session->nmea.cycle_enders);
> 3596         lasttag = session->nmea.lasttag;
> 3597         if (0 < session->nmea.lasttag) {
> 3598             lasttag_mask = (uint64_t)1 << lasttag;
> 3599         }
> 3600         if (0 < thistag) {
> > > >     CID 292260:  Integer handling issues  (BAD_SHIFT)
> > > >     In _expression_ "1UL << thistag", left shifting by more than 63 bits has undefined behavior.  The shift amount, "thistag", is as much as 70.  
> > > >           
> > >         
> >       
> 3601             thistag_mask = (uint64_t)1 << thistag;
> 3602         }
> 3603         if (session->nmea.latch_frac_time) {
> 3604             timespec_t ts_delta;
> 3605             TS_SUB(&ts_delta, &session->nmea.this_frac_time,
> 3606                               &session->nmea.last_frac_time);
> _____________________________________________________________________
>
> Before I change the algorithm to a different method, create a new set of
> bugs, can I just use uint128_t?  Or are there arches that do not have
> uint128_t?
>
> RGDS
> GARY
> ---------------------------------------------------------------------------
> Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
> 	address@hidden  Tel:+1 541 382 8588
>
> 	    Veritas liberabit vos. -- Quid est veritas?
>     "If you can't measure it, you can't improve it." - Lord Kelvin
>

--

Michael J Tubby B.Sc. (Hons) MIET / Technical Director
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