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<?xml-stylesheet type="text/xsl" href="https://community.arm.com/utility/feedstylesheets/rss.xsl" media="screen"?><rss version="2.0" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:slash="http://purl.org/rss/1.0/modules/slash/" xmlns:wfw="http://wellformedweb.org/CommentAPI/"><channel><title>CNTFRQ register on Cortex-A8</title><link>https://community.arm.com/developer/tools-software/tools/f/armds-forum/1087/cntfrq-register-on-cortex-a8</link><description> </description><dc:language>en-US</dc:language><generator>Telligent Community 10</generator><item><title>RE: CNTFRQ register on Cortex-A8</title><link>https://community.arm.com/thread/3339?ContentTypeID=1</link><pubDate>Wed, 11 Sep 2013 11:08:07 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:f6b52690-1868-467b-9331-b4703742e631</guid><dc:creator>Martin Weidmann</dc:creator><description>&lt;div&gt;&lt;i&gt;Note: This was originally posted on 21st October 2012 at &lt;a href="http://forums.arm.com"&gt;http://forums.arm.com&lt;/a&gt;&lt;/i&gt;&lt;br /&gt;&lt;br /&gt;&lt;span&gt;The forums (and the Cortex-A8 docs) are correct, this register is not present.&lt;/span&gt;&lt;br /&gt;&lt;span&gt;The ARM architecture includes a number of optional features. A given implementation (I.e. processor) chooses which of the optional features to implement. The CNTFRQ register is part of the optional Generic Timer spec.&amp;#160; As far as I know, only the CA15 and CA7 implement this.&lt;/span&gt;&lt;/div&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: CNTFRQ register on Cortex-A8</title><link>https://community.arm.com/thread/3338?ContentTypeID=1</link><pubDate>Wed, 11 Sep 2013 11:08:07 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:6bc49dd0-8f23-473d-8724-e835a1d2b23d</guid><dc:creator>John Conover</dc:creator><description>&lt;div&gt;&lt;i&gt;Note: This was originally posted on 22nd October 2012 at &lt;a href="http://forums.arm.com"&gt;http://forums.arm.com&lt;/a&gt;&lt;/i&gt;&lt;br /&gt;&lt;br /&gt;&lt;span&gt;Thanks,&lt;/span&gt;&lt;br /&gt;&lt;br /&gt;&lt;span&gt;&amp;#160; After going through the Architecture Reference Manual again, I see the optional sections listed in the beginning:&lt;/span&gt;&lt;br /&gt;&lt;span&gt;Floating-point (VFP) Extension&lt;/span&gt;&lt;br /&gt;&lt;span&gt;Advanced SIMD Extension&lt;/span&gt;&lt;br /&gt;&lt;span&gt;Security Extensions&lt;/span&gt;&lt;br /&gt;&lt;span&gt;Virtualization Extensions&lt;/span&gt;&lt;br /&gt;&lt;span&gt;&amp;#160; &lt;/span&gt;&lt;br /&gt;&lt;span&gt;&amp;#160; The Generic Timer is listed in chapter B8 and it mentions that it is optional. I guess that I expect the document to flow from a high level where the optional elements are listed, into a detailed view of how they work. It would have been nice if all the optional elements were listed in a single place. So when I came into the manual with assembly code from Linux on how to access the CNTFRQ register, I never made the connection that it is part of the Generic Timer (the assembly of how to access the CNTFRQ is listed in section B4.1, VMSA System control registers descriptions.)&lt;/span&gt;&lt;br /&gt;&lt;br /&gt;&lt;span&gt;Thanks again for the clarification.&lt;/span&gt;&lt;/div&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item></channel></rss>