The -march=armv7-a indeed solved all my problems. Thank you very much for all you answers.
So I eventually get a score around 94 for the v8 (version 3) tests with v8 on an OMAP3530 (Cortex A8 600MHz). I previously got a score around 800 on a 800Mhz Intel processor. The score gap is amazing for only 200MHz difference. I have not compared v8 arm and ia32 code. Do you know if this gap results from a better code optimization and/or better native code usage (I see a lot of posts relative to ARM work on the v8-dev group so I guess the ARM work is not yet to the level of the ia32's) or if the x86 architecture merely have a more efficient Instruction Set or architecture? Sorry to bother you with such weird (but interesting!) questions! Alexandre On Sep 9, 2:30 pm, Erik Corry <[email protected]> wrote: > 2009/9/9 Rames <[email protected]>: > > > > > In my hurry I didn't read your answers properly. Sorry for that. > > > My cpu is a Cortex A8 with an ARMv7-a version architecture and my gcc > > compiler uses #define __ARM_ARCH_4T__ 1 . > > Your gcc is designed by default to compile things that work with a > wide variety of ARM chips. V8 should work even with these pessimistic > assumptions, but you can't compile the VM in Thumb mode on such an old > chip. But as you note below you can use the -march flag to compile > for newer CPUs if you know you won't be running on such old hardware. > > > The patch you gave me didnt change the compile errors. > > I really don't know about ARM Instruction Set versions, but I hope > > this might help you to fix a potential bug. > > > Actually my problem is not to compile on the board itself, but rather > > to be sure that my tests results are accurate and it could be solved > > more easily if can you confirm me I can trust the cross-compiled shell > > obtained the following way: > > > 1) Modifying the v8 SConstruct adding 'CCFLAGS': ['- > > march=armv7-a'] to the arm architecture (line 162) > > 2) Exporting my environment variables CC, CXX, AR, AS, RANLIB, LD to > > my CodeSourcery crosstools (arm-none-linux-gnueabi-gcc , etc) > > 3) Cross-compiling with scons arch=arm sample=shell > > 4) Running the cross-compiled shell on my cpu > > That sounds fine and should give you a VM that works. To be certain, > there are some tests that are bundled with the VM source that you can > run with the test.py script. Seehttp://code.google.com/p/v8/wiki/Testing At > the moment we pass all > tests on ARM apart from some debug tests. There's a way to tell > test.py to use the ARM test expectations, but I can't remember it > right now. > > -- > Erik Corry, Software Engineer > Google Denmark ApS. CVR nr. 28 86 69 84 > c/o Philip & Partners, 7 Vognmagergade, P.O. Box 2227, DK-1018 > Copenhagen K, Denmark. --~--~---------~--~----~------------~-------~--~----~ v8-users mailing list [email protected] http://groups.google.com/group/v8-users -~----------~----~----~----~------~----~------~--~---
