<story><title>AMD Zen2 ymm registers rolling back</title><url>https://lkml.org/lkml/2023/2/22/33</url></story><parent_chain></parent_chain><comment><author>SethTro</author><text>&lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;lkml.org&amp;#x2F;lkml&amp;#x2F;2023&amp;#x2F;2&amp;#x2F;22&amp;#x2F;982&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;lkml.org&amp;#x2F;lkml&amp;#x2F;2023&amp;#x2F;2&amp;#x2F;22&amp;#x2F;982&lt;/a&gt;&lt;p&gt;Seems to be a known errata which was fixed by a microcode update</text></comment>
<story><title>AMD Zen2 ymm registers rolling back</title><url>https://lkml.org/lkml/2023/2/22/33</url></story><parent_chain></parent_chain><comment><author>snvzz</author><text>Lovely reminder of the mess x86 is.&lt;p&gt;fp registers shared with mmx, sse registers (xmm), avx registers (ymm), and a truckload of them.&lt;p&gt;Modern implementations have extremely complex frontends, full of elaborate hacks to get performance despite x86.&lt;p&gt;Complexity breeds bugs, such as this one.</text></comment>