[vlc-devel] [vlc-commits] commit: mtime: Avoid overflow when using mach_absolute_time(). (Pierre d' Herbemont )

Pierre d'Herbemont pdherbemont at free.fr
Sun Sep 26 13:29:27 CEST 2010

2010/9/26 Rémi Denis-Courmont <remi at remlab.net>:
>   Hello,
> On Sunday 26 September 2010, git at videolan.org wrote:
>> vlc | branch: master | Pierre d'Herbemont <pdherbemont at free.fr> | Sun Aug
>> 1 12:48:49 2010 +0200| [532b014ad9c53a3ef32a74373fdb895726bde516] |
>> committer: Pierre d'Herbemont
>> mtime: Avoid overflow when using mach_absolute_time().
>> Switch to double, do the operations and then convert back.
>> This fixes the iPad video freezes.
> Double precision operations are probably awfully slow on iPad. I am not aware
> of any ARM core that supports doubles in hardware. This may be neglectible
> because ARM does not support integer division (by a non-constant or non-power
> of two divisor) either. Still, double has less precision than int64_t so this
> seems like a regression to me.
> Why don't you use the same (integer) strategy as the Win32 code already does?

Nice point. I'll switch to 64bit integer and manually check the upper
bit overflow.



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