On 30/03/2019 14:59, Ryan Joseph wrote:
On Mar 30, 2019, at 9:10 AM, Jonas Maebe <jo...@freepascal.org> wrote: FPC always aligns data to its alignment as specified by the platform ABI. {$align x} can be used to limit this alignment to a lower number. It cannot be used to increase it.This caused us quite a bit of problems with the Metal framework because we needed padding fields also.
How is this done in the Metal C headers?
If you saw the original bug report we’re trying to make a custom alignment (of 4k) for the Metal framework. I propose the syntax because it solves the problem of how to assign alignment and there is a precedent for it (i.e. $align).
No, I missed that. In that case, a vector type won't help. The best way then is, as has been mentioned elsewhere in this thread, a getmem variant that supports allocating memory on an aligned boundary. Similar to how unix platforms have posix_memalign.
This falls outside the scope of direct support in the language, so a solution like Anthony's is better in this case if you want to encapsulate it completely.
Can you give some examples of the vector type? I don’t exactly know what you guys are referring to.
A vector type is basically a (fairly small) array of integer or floating point types. All current desktop (and many embedded) CPUs have special execution units that operate on all elements of such vectors in parallel, which means you can get better performance.
Jonas _______________________________________________ fpc-devel maillist - fpc-devel@lists.freepascal.org http://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-devel
