Pedro Alves a écrit : > Danny Backx escreveu: >> On Wed, 2007-09-19 at 17:51 +0200, pgeorges wrote: >>>> Crosswords, compiled with cegcc, runs noticably slower than compiled >>>> with the m$ compiler. Eric House also reported this. I've not >>>> investigated this yet. We may have inefficiencies other than the code >>>> generated by the compiler. Something with the coredll perhaps ? >>>> >>>> Danny >>>> >>> Is it possible to know in which cases the slowdowns are encountered >>> ? CPU intensive code, I/O , system calls ? >>> What is the amount of slow down ? 10 % , 50 % ? >>> >>> Pascal >> >> I don't have an eVC4 installed (only my children have Windows PC's) so I >> have no simple way to do comparisons. >> >> Xwords shows a noticable difference if you get it to refresh its screen. >> (It's a scrabble game application.) When compiled with cegcc, you can >> see how it draws the game board - takes one or 1.5 seconds. With the >> executable as you can download it from http://xwords.sf.net , the redraw >> is instantaneous. >> >> So that example could lead you to the conclusion that it's either >> graphics or system (DLL?) access. >> > > I doubt it. There shouldn't be any difference in calling system > functions. > It's just a bl anyway. > > Your example is about floating point arithmetic. Is Xwords doing it a > lot? > > Pgeorges, is you chess engine doing a lot of fp math? > My application uses a lot integer and floating point calculation, but more integer than floating point, I guess. But if I remember well the first SPARC processors, they used 120 CPU cycles for a mere division, because of the lack of FPU, so even if the FP instructions are used 1% of the time (compared to integer), they can lead to a use of 50% of the CPU. > We currently generate code that assumes that the device *does not* > have an fpu. The processor of my PPC is a PXA 270 which does not have a FPU (correct me if I am wrong).
Pascal ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2005. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ Cegcc-devel mailing list Cegcc-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/cegcc-devel
