[PATCH 5/8] ntdll: Add detection for PF_SSE_DAZ_MODE_AVAILABLE

James Eder jimportal at gmail.com
Sun Oct 21 17:16:04 CDT 2012

Hmmm... the GCC docs say:


"Note that the alignment of any given struct or union type is required
by the ISO C standard to be at least a perfect multiple of the lowest
common multiple of the alignments of all of the members of the struct
or union in question. This means that you can effectively adjust the
alignment of a struct or union type by attaching an aligned attribute
to any one of the members of such a type, [...]"

So, with conforming compilers, the having M128A aligned makes
XMM_SAVE_AREA32 aligned. I tried it out some and I wasn't able to find
a case which GCC (4.7.2) didn't align XMM_SAVE_AREA32 at 16 with M128A
declared the way it is.

The documentation goes on to say:

"Note that the effectiveness of aligned attributes may be limited by
inherent limitations in your linker. On many systems, the linker is
only able to arrange for variables to be aligned up to a certain
maximum alignment. (For some linkers, the maximum supported alignment
may be very very small.) If your linker is only able to align
variables up to a maximum of 8 byte alignment, then specifying
aligned(16) in an __attribute__ will still only provide you with 8
byte alignment. See your linker documentation for further

Seems to work fine for me without the manual alignment, but I that
doesn't say much for anyone using some other compiler/linker.  Not
that I care about those unfortunate souls :P.  I was just going for
what I figured would get the patch in.  Either way will work well
enough for me.  So I guess I just need to know which way will get the
patch in. :)


More information about the wine-devel mailing list