Re: Why align all pinned array payloads on 16 bytes?

The SSE types require 16-byte alignment. Most of the original SSE instructions have versions that accept non-aligned data though. Alexander On Tue, Oct 16, 2018 at 11:18 PM Simon Marlow wrote:

I vaguely recall that this was because 16 byte alignment is the minimum you need for certain foreign types, and it's what malloc() does. Perhaps check the FFI spec and the guarantees that mallocForeignPtrBytes and friends provide?

Cheers Simon

On Thu, 11 Oct 2018 at 18:44, Ömer Sinan Ağacan wrote:

...

Hi,

I just found out we currently align all pinned array payloads to 16 bytes and I'm wondering why. I don't see any comments/notes on this, and it's also not part of the primop documentation. We also have another primop for aligned allocation: newAlignedPinnedByteArray#. Given that alignment behavior of newPinnedByteArray# is not documented and we have another one for aligned allocation, perhaps we can remove alignment in newPinnedByteArray#.

Does anyone remember what was the motivation for always aligning pinned arrays?

Thanks

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