http://blog.frohling.biz Niels Fröhling about [X]HTML, JS and technical tidbits Sat, 21 Aug 2010 19:13:15 +0000 http://backend.userland.com/rss092 en Currently I'm experimenting with jQuery (always being told prototype.js is evil). In my project I have to make quite some complex animations and I tried to detect if I can map them to the animate() syntax. Uh, and all hell broke loose. Here is my 24h experience: You can't animate regular ... http://blog.frohling.biz/2010/08/jquerys-animate-is-short-thought/ Uh, sometimes you don't know what's in the mind of intel guys. They state in their documentation that the movntq-op (taken over from MMXExt) has to take place on 16-byte aligned memory. What??? Either it's a copy & paste error, it's probably suppose to mean 8-byte aligned memory, or you got ... http://blog.frohling.biz/2010/04/movntq-alignment/ pavgd (32bit average [(a + b + 1) >> 1]: /* add (a + b), and compare overflow */ movq mm6, mmc paddd mmc, mmd psubd mm6, 0x80000000 psubd mmc, 0x80000000 pcmpgtd mm6, mmc paddd mmc, 0x80000000 /* add (ab + 1), and compare overflow */ pcmpeqd mm5, mm5 pcmpeqd mmd, mmd pcmpeqd mm5, mmc psubd mmc, mmd /* shift carry in */ por mm6, mm5 pslld mm6, 31 psrld mmc, 1 por mmc, mm6 http://blog.frohling.biz/2010/02/op-equivalent-series-pavgd/ psubq (64bit - 64bit = 64bit): movq mm7, mmc psubd mmc, mms movq mm6, mmc psubd mm7, 0x80000000 psubd mm6, 0x80000000 pcmpgtd mm6, mm7 psllq mm6, 32 psubd mmc, mm6 http://blog.frohling.biz/2010/01/op-equivalent-series-psubq/ paddq (64bit + 64bit = 64bit): movq mm7, mmc paddd mmc, mma psubd mm7, 0x80000000 psubd mmc, 0x80000000 pcmpgtd mm7, mmc paddd mmc, 0x80000000 psllq mm7, 32 psubd mmc, mm7 http://blog.frohling.biz/2010/01/op-equivalent-series-paddq/ packusqd (saturated clamp from unsigned long long to unsigned long), packssqud (saturated clamp from signed long long to unsigned long): There is a condition for unsigned long long inputs, range is "only" [0x0000000000000000, 0x7FFFFFFFFFFF]. There is a no condition for signed long long inputs. // from-scratch, no helper available /* -1 ... http://blog.frohling.biz/2010/01/op-equivalent-series-packusqd/ packusdw (saturated clamp from unsigned long to unsigned short), packssduw (saturated clamp from signed long to unsigned short): There is a condition for unsigned long inputs, range is "only" [0x00000000, 0x7FFFFFFF]. There is a condition for signed long inputs, range is "only" [0x80008000, 0x7FFFFFFF]. You can go to full signed long if there ... http://blog.frohling.biz/2010/01/op-equivalent-series-packusdw/ The SSE-ops lack a huge amount of very usefull functions. Basically every single mathematical relevant function is absent, worst, trying to re-create them and reach the same precision as the FPU-routines results in magnitude slower code. Sometimes one can find a usefull short-cut, but not very often. Here I tried to ... http://blog.frohling.biz/2010/01/cubic-root-approximation/ padddq (128bit + 64bit = 128bit): // carry emulation via pcmpgtq equivalent movdqa xmmx, xmma movdqa xmmy, xmmb movdqa xmmz, xmma paddq xmma, xmmb pcmpgtd xmmx, xmmb pcmpgtd xmmy, xmma pcmpeqd xmmz, xmmb pshufd xmmx, xmmx, 1|1|1|1 pshufd xmmz, xmmz, 1|1|1|1 pand xmmz, xmmy por xmmz, xmmx punpcklqdq xmmz, xmmz pslldq xmmz, 8 or pshufd psubq xmma, xmmz http://blog.frohling.biz/2010/01/op-equivalent-series-padddqd/ When you don't have SSE4 available you have to compensate for the lack of ome essencial ops. In this series I'm going to write down equivalents of either missing or (currently) non-AMD ops. pcmpeqq (64bit integer compare): // equality == (hi == hi) && (lo == lo) movdqa xmm?3, xmma pcmpeqd xmm?3, xmmb pshufd xmm?1, xmm?3, 3|3|1|1 (b == ... http://blog.frohling.biz/2010/01/op-equivalent-series-pcmpgtq-pcmpeqq/