Re: yuvdeinterlace
"Scott Smith" <[email protected]>
| Newsgroups | gmane.comp.video.mjpeg.devel |
|---|---|
| Message-ID | <[email protected]> |
On 2/23/07, stefan <[email protected]> wrote: > Could someone explain me, why it must be aligned to 16 bytes? 8 bytes I > would understand (quad-word) but 16?!? Is this really necessary? I can't for Altivec, but I can for sse... it fits in a cache line better. SSE has two load instructions, movaps and movups. movaps is for things aligned on 16 byte boundaries; movups is for things not aligned. movups is slower. Internally, I believe movups is (or was at one point) implemented as two separate 16-byte aligned reads, with the appropriate shifts. Something about the interface to the cache only accepting reads withing 16-byte boundaries. My guess is Altivec doesn't even have movups. -- Scott ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV