[Tinyos-devel] TinyOS-2.x platform independent types?

[Matti Juhani Öhman]

  Hi all,

  what is the current status of TinyOS platform independent types (aka 
network types)? I am trying to compose a message structure with 24-bit 
little endian integers with no success.

  The most useful source of information I could find is the TinyOS 
Programming Manual. It explains platform independent types it does not
mention bit fields at all.

  I did some test with the nesC compiler. It seems that big endian types 
support bit fields but little endian types do not:

typedef nx_struct test_t  {
   nx_uint32_t a:24;
   nx_uint32_t b:24;
   nx_uint32_t c:24;
   nx_uint32_t d:24;
} test_t;

-> compiles just fine, but


typedef nx_struct test_t  {
   nxle_uint32_t a:24;
   nxle_uint32_t b:24;
   nxle_uint32_t c:24;
   nxle_uint32_t d:24;
} test_t;

-> gives a compiler error: "type of `a' cannot be used as a bit-field"


  Shouldn't it be possible to declare little endian bitfields?

  The supported platform independent big endian (little endian) types are:

  nx_uint8_t   (nxle_uint8_t)  -> 1 byte
  nx_uint16_t  (nxle_uint16_t) -> 2 bytes
  nx_uint32_t  (nxle_uint32_t) -> 4 bytes


  For completeness, the following types could also be supported:

  nx_uint24_t  (nxle_uint24_t) -> 3 bytes


  The big endian version (nx_uint24_t) can be simulated with bit fields (as 
above), but the little endian version cannot? Am I missing something?


  Cheers,

   Matti