plz explain this.. #define statement - mc1321x ZigBee

[kanu]

me a starter in embedded programming, i m trying to understand the start code for mc1321x based SRBboard, i amnot able to figure out the use of two parenthesis

specifically this part- } _FEED_COP(); __asm {

as in the following statement.this is from start08.c .

----------------------------------------------!--------------------------------!
#define __FEED_COP_IN_HLI() } _FEED_COP(); __asm {
regards.. karan

Message Edited by kanu on 2008-10-19 10:37 PM

Message Edited by kanu on 2008-10-19 10:38 PM

Message Edited by kanu on 2008-10-19 10:41 PM

Added p/n to subject.

Message Edited by NLFSJ on 2008-10-20 10:31 AM

[kanu]

i got that..
thanx daniel... thnxx a lot..



regards...
karan

[CompilerGuru]

Look how the macro is used:

Code:

  asm {
...
             AIX    #1
             __FEED_COP_IN_HLI()      ; // it's necessary to feed the COP in the inner loop for the fast COP timeout of some derivatives
Zero_0:
             DBNZA  Zero_2
.....
  }

The _FEED_COP cannot be used in a HLI, its written so that it has to be called in a C code area.
Therefore the  __FEED_COP_IN_HLI macro first closes the open asm { block with a single brace },
the
 __asm {
part at the end reopens the HLI block again.

Note that the __FEED_COP_IN_HLI macro is defined in a C file for a particular usage,
for the general (C code) case, use the _FEED_COP macro.

If you do not understand how in C a particular macro works, I would suggest to check the generated preprocessor output.

Daniel