[ECOS] Question about CYG_HAL_TABLE usage

[Grant Edwards <grant.b.edwards@gmail.com>]

I'm working with an app that uses the CYG_HAL_TABLE macros for seveal
different purposes.  I've always thought that the "END" label was at
the end of the "array" of objects, such that you can iterate a table
like this:


  for (p = __foo_TAB__; p < __foo_TAB_END__; ++p)
    {
      // process object pointed to by p    
    }    

But this seems not to be the case.  At least for Cortex M3 targets The
END label is aligned on an 8-byte boundary so that there may be up to
7 bytes of padding between the end of the table and the END label.

This means that 

 * If you use HAL_TABLE macros for objects smaller than 8 bytes, you
   have no way of knowing where the table actually ends.

 * If object size isn't a mulitple of 8, the last iteration in the
   loop above points to garbage.

Am I understanding this correctly?

Are there asserts that will detect an attempt to use a HAL_TABLE with
objects < 8 bytes long?

If I do understand the implementation, then the loop needs to be

  for (p = __foo_TAB__; p+1 <= __foo_TAB_END__; ++p)
    {
      // process object pointed to by p
    }
    
But again, that requires that object size be >= 8 bytes.

    
-- 
Grant Edwards               grant.b.edwards        Yow! Am I accompanied by a
                                  at               PARENT or GUARDIAN?
                              gmail.com            


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