When I have bits using them as bit variables or flags, I set them as this:

Code:
my_flag    var byte
  flag1      var my_flag.0
  flag2      var my_flag.1

etc
Also recently Darrel gave a tip for a calculation.

Code:
IF ABS(x-y)>16 THEN...
Using this:

Code:
IF X>Y THEN
    Z=X-Y
ELSE
   Z=Y-X
ENDIF
which compiles about the half size.

So, a little common sense and experimenting is all that is needed.

Ioannis