Question about CYG_HAL_TABLE usage

Grant Edwards <[email protected]>
Newsgroups gmane.os.ecos.general
Message-ID <[email protected]>
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            


-- 
Before posting, please read the FAQ: http://ecos.sourceware.org/fom/ecos
and search the list archive: http://ecos.sourceware.org/ml/ecos-discuss
lmpx.com only provides a reader for public news (NNTP) servers. It is not affiliated with the servers or forums shown here and is not responsible for the content of articles, which is written by their respective authors.