schrieb Albert Cahalan on 2013-01-28 21:13: > On Mon, Jan 28, 2013 at 7:28 AM, Patrick Strasser
> Most people would be surprised at what gcc can do these days. > > You can help with good hinting. It's important to let the compiler > know when aliasing and alignment won't be an issue. Hinting is good, forcing probably not... >>> An interesting question related to this: Suppose that 50% of the platforms >>> can >>> handle the codec in real-time. Changing code generation increases that to >>> 70%, >>> but makes the remaining 30% unable to run the codec at all. Is that good or >>> bad? >> >> What do you mean with "unable"? Just won't run, lacking some features it >> is compiled for, or running unbearable slow? > > refuse to run, or an immediate crash IMO this must be avoided. If word spreads that it just won't run on certain random) hardware, were done. I think you can optimize and let it run on decent hardware. Probably support fir i368 is not necessary any more... >> be potential for performance optimizations. Some people think it can run >> properly on some embedded architectures without floating point support, >> but then again this needs porting to fixed point and some expertize in >> this field. > > Maybe this can be done w/o making the code too ugly. > I think the latest C standard has some fixed-point features. > It was at least a proposal, and I think gcc implemented it. I never dived into fixed point arithmetics. For sure it would allow to run Codec2/FDMDV on platforms without floating point support. But would it gain anything on the other platforms? >>> There is also the question >>> of how much CPU power must be left for other things in order to be >>> practical, >>> and the question of half-duplex vs. full-duplex. >> >> Full duplex is not common in amateur radio. First because only one >> frequency is used and TDM is not feasible, second because most >> transceivers do not support full duplex. It's kind of a problem to hear >> anything when you are sending with 100s of Watts, without proper duplex >> spacing. > > Do the radios switch too slowly for TDM? What can a good one do? Switching time is in the order of 100s of miliseconds. Anyway, amateur radio operators are very happy with half duplex. It leads to good manners and courtesy ;-) It's been like that for more than 100 years, no big problem until now. >> For other scenarios, like VoIP, duplex is probably reasonable, but I'm >> not sure if you are strongly limited in computational power in such >> situations. > > I think you can become severely limited, even on modern server hardware. > You may be handling numerous calls at once. I've heard "thousands" for > the free VoIP software on Linux. Ok, point taken. Optimization is no bad idea even for big iron. Regards Patrick -- Engineers motto: cheap, good, fast: choose any two Patrick Strasser <patrick at wirklich priv at> ------------------------------------------------------------------------------ Master Visual Studio, SharePoint, SQL, ASP.NET, C# 2012, HTML5, CSS, MVC, Windows 8 Apps, JavaScript and much more. Keep your skills current with LearnDevNow - 3,200 step-by-step video tutorials by Microsoft MVPs and experts. ON SALE this month only -- learn more at: http://p.sf.net/sfu/learnnow-d2d _______________________________________________ Freetel-codec2 mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/freetel-codec2
