[Tinyos Core WG] 109 and left shifting

[Philip Levis]

One last gasp on the no-shifting vs. left shifting question. One of  
my original motivations on why left shifting was useful is that it  
allows you to know the general magnitude of the value without having  
to know how many significant bits it has. E.g., I see

01 30

In my hex packet dump, or 304 decimal, and I know the value is small.  
In contrast, if I am not left shifted, the data does not tell me how  
many significant digits there are and so I have no idea if this is,  
for example, 60% of the max (9 bits, 0x01ff), 30% of the max (10  
bits, 0x3ff), or 7% of the max (12 bits).

Of course, losing the size of the type (uint16_t -> java signed  
integer) can hurt you. But otherwise you either need Java to be able  
to correlate the data value with a particular sensor driver or send  
the significant bits inline.

Phil