64 bits aligned

evilo · Post by **evilo** » Wed Jul 14, 2004 7:19 pm

HI all,

may be it will be a stupid question for you, but on my side I still don't know exactly in which cases buffers need to be 64 bits aligned...

And what are the side effects on non aligned buffers ?

I searched the forum, look at a few sources, and this is not always the case !!

Thank you :)

evilo

Post by **blackdroid** » Wed Jul 14, 2004 8:33 pm

64 bits is not enough. 128bits ( 16 bytes ) alignment is needed for all dma transfers.

evilo · Post by **evilo** » Wed Jul 14, 2004 9:33 pm

Ok,
but without speaking of dma transfert ?

is it needed for buffers declarations ?

Post by **blackdroid** » Wed Jul 14, 2004 9:52 pm

without dma ( first off, nearly anything you do on this machine is for dma'ing ) you only need to care about alignment for the datawidth you are using, and that is more for performance. so if you are going to read int's float's align to 4 bytes.