While I agree it's good to avoid floating point numbers when doing integer math, this optimization may or may not have a significant affect your app's overall FPS, depending on what else it is doing. I would recommend profiling it, for example with TraceView: http://developer.android.com/guide/developing/tools/traceview.html#profilepanel
Yusuf Saib Android ·T· · ·Mobile· stick together The views, opinions and statements in this email are those of the author solely in their individual capacity, and do not necessarily represent those of T-Mobile USA, Inc. On May 20, 11:42 pm, Al Sutton <a...@funkyandroid.com> wrote: > Ahhh... those were the days.... bitshifting instead of multiplication & > dividing.... XORing a value by itself being quicker than setting it to zero > (seehttp://en.wikipedia.org/wiki/Bitwise_operation#XORif you think I'm making > this one up, it was certainly true on a Motorola 68000 embedded system I > worked on). > > Nowadays this is all normally done automatically by the compiler as an > optimisation, so you may not see any benefit doing it explicitly in the code > except for making new coders go "wtf is that about?" :). > > Al. > > --- > > * Written an Android App? - List it athttp://andappstore.com/* > > ====== > Funky Android Limited is registered in England & Wales with the > company number 6741909. The registered head office is Kemp House, > 152-160 City Road, London, EC1V 2NX, UK. > > The views expressed in this email are those of the author and not > necessarily those of Funky Android Limited, it's associates, or it's > subsidiaries. > > > > -----Original Message----- > From: android-developers@googlegroups.com > [mailto:android-develop...@googlegroups.com] On Behalf Of Jason Proctor > Sent: 20 May 2009 23:30 > To: android-developers@googlegroups.com > Subject: [android-developers] Speed: Divide by two or multiply by .5? - I > wrote a little FPS performance tester to find out. > > maybe i'm missing the point here, but dividing by a power of 2 can be > done very fast by right-shifting. hard to beat that. > > >Romain - The idea was to see which is faster to cut an int in half - > >multiplying by a float (.5) or dividing by two. I've read that > >divides are terribly slow but apparently not as bad as floating point > >multiplications w/ a cast back to an int. > > -- > jason.software.particle --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Android Developers" group. To post to this group, send email to android-developers@googlegroups.com To unsubscribe from this group, send email to android-developers-unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/android-developers?hl=en -~----------~----~----~----~------~----~------~--~---
