Date: Sun, 8 Jul 2012 10:51:54 +0530 From: Sayantan Datta <std2048@...il.com> To: john-dev@...ts.openwall.com Subject: Rotate and bitselect investigation Alexander and all, I have investigated the rotate and bitselct issue on 7970. Both type of rotate(manual and inbuilt opencl function) use bitalign instruction. I investigated using rotate(x,(uint)30) and ((x << 30) | ((x ) >> 2)). Also the values loaded in the bitalign instructions are exactly same except they operate on different registers. So you won't see any performance increase in this case. However with bitselct the situation is different. The inbuilt function uses an alien bfi instruction which I couldn't find anywhere in the docs. The manual version uses ixor and iand. Regards, Sayantan Content of type "text/html" skipped
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