Hi Alexandre,

I think that our issue is caused by Math.random() and not Math.floor()
because:
on mac:
 >Math.random()
 0.8807874456979334

on arm:
 >Math.random()
 8.263547083e-315 // 0.00000000000...826 so floor should return 0 most
of time.

but on arm:
 >Math.floor(2.1534)
 2

So floor seems to work correctly if the number is not to big.

Best regards,
Julien

On Dec 2, 5:02 pm, Alexandre Rames <[email protected]> wrote:
> Hi Julien,
>
> I don't have actual ARM4 hardware, but everything works fine for me on the
> Simulator when disabling armv7 and vfp3 (equivalent to using armv4 on v8).
>
> I don't know too much about the Date issue. It looks like something is wrong
> in the bindings between v8 and your system.
>
> A few hints for the Math.floor issue:
> - Use a debug version of the shell to debug / carry your tests.
> - Do you pass the cctests?
> tools/test.py --snapshot --mode=debug -j3
> - Especially do you pass the mjsunit/math-floor.js test?
> ./shell_g --enable-slow-asserts --debug-code --verify-heap
> --max-new-space-size=256 test/mjsunit/mjsunit.js test/mjsunit/math-floor.js
>
> - You may want to check the hex value returned by your call to Math.floor
> with gdb / ddd.
> ARMv4 does not use an assembly optimization for Math.floor, so it seems
> unlikely that the result of the computation is false.
> You can try check the double returned by v8 to see if it is correct.
> I could not confirm on a quick test that v8::internal::Runtime_Math_floor
> (runtime.cc) is called, but you may want to put a breakpoint there.
> Otherwise v8 may call a builtin. You can use a breakpoint (with a counter to
> stop at the right time) in v8::internal::Invoke (execution.cc) around value
> = CALL_GENERATED_CODE(... (~line 94) .
>
> I found an interesting issue while investigating your bug: compiling the
> shell in debug mode with the snapshot option on and running with
> noenable_armv7 and noenable_vfp3 generates some incoherency: natives are
> compiled with vfp3 and armv7, so we still execute this code when calling
> them!
> But this has nothing to do with your bug. This won't happen on actual
> hardware, and you would get an illegal instruction exception or so.
>
> Cheers
>
> Alexandre
>
>
>
>
>
>
>
> On Thu, Dec 2, 2010 at 11:35 AM, JulienC <[email protected]> wrote:
> > We are currently using uClibC, it works well for all the system we
> > have (glib + protocol buffer + mplayer + ...).
>
> > We compile V8, it almost work. But Math.random() returns
> > "8.263547083e-315" and the strange issue for the date.
>
> > I cannot find if it comes from V8 or uClibC.
>
> > I've tried unsuccessfully to use a standard libC in our environment
> > but it a to complex modification in our system.
>
> > Do you have any idea ?
>
> > Best regards.
> > Julien.
>
> > On Nov 26, 1:29 pm, Rodolph Perfetta <[email protected]>
> > wrote:
> > > Hi,
>
> > > I couldn't reproduce your issue, an armv4 build of bleeding_edge gives me
> > > the right result.
>
> > > Are the C libraries on your platform working properly? Could you try and
> > > narrow it down a bit: is it Math.floor or Math.random (or both) which is
> > an
> > > issue?
>
> > > Cheers,
> > > Rodolph.
>
> > > On 25 November 2010 14:09, JulienC <[email protected]> wrote:
>
> > > > Hi all,
>
> > > > I currently encounter 2 issues with V8 on armV4 (arm920t), I don't
> > > > know if they are related or not.
>
> > > > The first is with Math.random() when I try to get a number in 0-9,
>
> > > > on my mac, it works well:
> > > >  >Math.floor(Math.random()*10)
> > > >  2
>
> > > > on armV4, strange behaviour:
> > > >  >Math.floor(Math.random()*10)
> > > >  1.6427083566e-314
>
> > > > I'm using the trunk but it seems to do the same for all versions.
>
> > > > The second issue is concerning the Date object, when I try to set a
> > > > date, it always return 01/01/1970...
>
> > > > on my mac:
> > > >  > new Date()
> > > >  Thu Nov 25 2010 14:59:26 GMT+0100 (CET)
> > > >  > new Date(2009, 11, 30)
> > > >  Wed Dec 30 2009 00:00:00 GMT+0100 (CET)
>
> > > > on armV4:
> > > >  > new Date()
> > > >  Thu Nov 25 2010 00:00:00 GMT+0000 (UTC)          //no time ?
> > > >  > new Date(2009, 11, 30)
> > > >  Thu Jan 01 1970 00:00:00 GMT+0000 (UTC)          // wrong date !
>
> > > > I hope that someone has any idea about one of those issues.
>
> > > > Best regards.
>
> > > > --
> > > > v8-users mailing list
> > > > [email protected]
> > > >http://groups.google.com/group/v8-users
>
> > --
> > v8-users mailing list
> > [email protected]
> >http://groups.google.com/group/v8-users

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