On Wed, Oct 04, 2006 at 03:00:34PM -0400, janani@linux.ibm.com wrote:
> I am new to this, so my interpretation might not be completely >
accurate, but the way I read the note below ( a snippet from the GNU
> GCC Manual about passing function arguments in registers) is that
> since PPC64 is big endian, even though the default is to pad
downward > (i.e. right align), if the size if greater than the size
of an int, > you need to pad upward (left align).
You're trying to answer the wrong question :-)
It's not "what does GCC do", but "what does the platform ABI say we
should do". Is GCC conforming to the ABI? Is the ABI wrong, or out of
date, or was Andrew's reading of it wrong, or...
There could be a real problem here, so it's important that we
understand what is _supposed_ to happen before we make a change.
If GCC is violating the ABI, then either GCC or the ABI may need to be
updated. If GDB is misinterpreting the ABI, then just GDB needs to be
changed.
--
Daniel Jacobowitz
CodeSourcery
! /* WARNING: cagney/2003-09-21: As best I can
! tell, the ABI specifies that the value should
! be left aligned. Unfortunately, GCC doesn't
! do this - it instead right aligns even sized
! values and puts odd sized values on the
! stack. Work around that by putting both a
! left and right aligned value into the
! register (hopefully no one notices :-^).
! Arrrgh! */
! /* Left aligned (8 byte values such as pointers
! fill the buffer). */
! memcpy (regval, val + byte, len);
! /* Right aligned (but only if even). */
! if (len == 1 || len == 2 || len == 4)
! memcpy (regval + tdep->wordsize - len,