From: Grant Edwards <grant.b.edwards@gmail.com>
To: ecos-discuss@ecos.sourceware.org
Subject: [ECOS] Question about CYG_HAL_TABLE usage
Date: Fri, 11 Oct 2013 21:48:00 -0000 [thread overview]
Message-ID: <l39rn8$hu$1@ger.gmane.org> (raw)
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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next reply other threads:[~2013-10-11 21:48 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-11 21:48 Grant Edwards [this message]
2013-10-11 23:16 ` Daniel Helgason
2013-10-12 15:19 ` [ECOS] " Grant Edwards
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