March 2006 - Darwin-kernel - lists.apple.com

Re: A float point arithmetic in kernel extension
by Graham J Lee 09 Mar '06

09 Mar '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com On 9 Mar 2006, at 02:45, wlq wrote: Thank you. I have done it and It works well. But, the table is not large enough to fill all the point. -- Graham Lee GPG Key ID: 01D5B9D8 UNIX Systems Manager, Oxford Physics Practical Course http://users.ox.ac.uk/~wadh1342 01865 273450 _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… This email sent to site_archiver(a)lists.apple.com OK, you can interpolate between table entries for points which aren't covered in the table. A linear correction might be good enough, but I wonder whether there's a straightforward way to devise a quadratic correction, given that gamma is "about 2"[*] for a lot of display equipment. [*]I think it's 1.8 for almost all CRTs and 2.2 for some old-school Macintosh displays. smime.p7s

1 0

Re: A float point arithmetic in kernel extension
by wlq 09 Mar '06

09 Mar '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Thank you. I have done it and It works well. But, the table is not large enough to fill all the point. I hope the next version's coming. _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… This email sent to site_archiver(a)lists.apple.com

1 0

Re: Kernel debug kit for 10.4.5
by Garth Cummings 08 Mar '06

08 Mar '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… This email sent to site_archiver(a)lists.apple.com

1 0

Re: Kernel debug kit for 10.4.5
by Michael Tuexen 08 Mar '06

08 Mar '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Hi Garth, see my comments in-line. Best regards Michael On Mar 8, 2006, at 8:18 PM, Garth Cummings wrote: Hi Michael, On Mar 8, 2006, at 10:51 AM, Michael Tuexen wrote: Did you look in the usual places: <http://developer.apple.com/devicedrivers/download> <http://developer.apple.com/sdk>? No, I did not, thanks for the link. I just looked at http://developer.apple.com/sdk/ ____________________________________________________________________ Garth Cummings gcummings(a)apple.com Sr. Software Engineer Apple Developer Technical Support http://developer.apple.com/technicalsupport _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… will there be a kernel debug it available for Mac OS X 10.4.5? This email sent to site_archiver(a)lists.apple.com

1 0

Re: Kernel debug kit for 10.4.5
by Shawn Erickson 08 Mar '06

08 Mar '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Domainkey-signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=GmDwp362+MC7dYzY/JXp2MqKxr3oFpG+mdJZUcYEygWQS+bOReS09+rHebKdNFe9uiEPUwsE3wNHaU3n32ekyuxYMmRc20agVhPiRRmppBdjXInH/CV+8vwzrXUAVq0XQ/K1g8LExUnHu20eJlxk91JK+RhWtO8sSx74xNdmAck= On 3/8/06, Garth Cummings <gcummings(a)apple.com> wrote: > Hi Michael, > > > On Mar 8, 2006, at 10:51 AM, Michael Tuexen wrote: > > will there be a kernel debug it available for Mac OS X 10.4.5? > > Did you look in the usual places: > > <http://developer.apple.com/devicedrivers/download> I found it on... <http://developer.apple.com/devicedrivers/download/kerneldebugkits.html> ...but the following only lists 10.4.4 when in likely should list 10.4.5. > <http://developer.apple.com/sdk>? -Shawn _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… This email sent to site_archiver(a)lists.apple.com

1 0

Re: Kernel debug kit for 10.4.5
by Garth Cummings 08 Mar '06

08 Mar '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… This email sent to site_archiver(a)lists.apple.com

1 0

Kernel debug kit for 10.4.5
by Michael Tuexen 08 Mar '06

08 Mar '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Hi, will there be a kernel debug it available for Mac OS X 10.4.5? Best regards Michael _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… This email sent to site_archiver(a)lists.apple.com

1 0

Re: A float point arithmetic in kernel extension
by Graham J Lee 08 Mar '06

08 Mar '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com On 8 Mar 2006, at 02:39, wlq wrote: This all presupposes that you *need* to be using the kernel for this... [*]which is indeed how a NeXT would have done it, only in hardware. -- Graham Lee GPG Key ID: 01D5B9D8 UNIX Systems Manager, Oxford Physics Practical Course http://users.ox.ac.uk/~wadh1342 01865 273450 _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… This email sent to site_archiver(a)lists.apple.com I want to calculate gamma curve in kernel extension. Now that you can do with some lookup tables[*], and using fixed-point (i.e. integers). Given that a "gamma" curve has a single parameter gamma, and maps luminosity to input signal via a power law (L=x^gamma give or take a constant), we can rearrange this stuff: L=exp(gamma*log(x)) where the log is natural (i.e. base e). You can do tables for log and exp; that's all our computers used to do when they were salaried staff. The error on your final answer is proportional to the accuracy of your lookups/interpolations. smime.p7s

1 0

Re: A float point arithmetic in kernel extension
by Graham J Lee 08 Mar '06

08 Mar '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Sorry darwin-dev@, I wasn't quite paying attention there... :-( On 7 Mar 2006, at 12:04, Graham J Lee wrote: Cheers, _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… This email sent to site_archiver(a)lists.apple.com On 7/3/06 05:53, wlq wrote: I am building one kernel extension for my device and I need do some float point arithmetic. The problem is, In my code, I have added header file #include <math.h> And I have called some float point function pow(float, float), acos (float) etc. Actually, pow() and acos() take double arguments, though there are float equivalents. How precise and over how much of a range do you need your results? You could get away with fixed-point arithmetic or a lookup table in some circumstances (though don't wire down a 250MB lookup table; I'm speaking as a Spectrum[*] programmer :-). You don't need even 'float'-level precision for some tasks. Graham. [*]TS 1000, transatlantic brethren (and sistren) -- Graham Lee UNIX Systems Manager, Oxford Physics Practical Course http://users.ox.ac.uk/~wadh1342 _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/leeg% 40teaching.physics.ox.ac.uk This email sent to leeg(a)teaching.physics.ox.ac.uk smime.p7s

1 0

Re: A float point arithmetic in kernel extension
by wlq 08 Mar '06

08 Mar '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com I want to calculate gamma curve in kernel extension. Thank you. ----- 原始邮件 ----- 发件人: "Mike Smith" <drivers(a)mu.org> 收件人: "wlq" <weiliqun(a)vimicro.com> 抄送: <darwin-kernel(a)lists.apple.com> 发送时间: 2006年3月7日 18:28 主题: Re: A float point arithmetic in kernel extension On Mar 6, 2006, at 9:58 PM, wlq wrote: > I have tried this for a long time, I think maybe asm can do. > But where to find any information about asm programme in xcode? No, this won't help. Floating point operations in general are not supported in the kernel. You will need to find a different way to solve your problem. What exactly are you trying to do? = Mike _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… This email sent to site_archiver(a)lists.apple.com

1 0