<p><span class="h-card" translate="no"><a href="https://mastodon.gamedev.place/@rygorous" class="u-url mention">@<span>rygorous</span></a></span> <span class="h-card" translate="no"><a href="https://tech.lgbt/@snowfox" class="u-url mention">@<span>snowfox</span></a></span> oh perfect, this is exactly what i was wondering about!</p>

<p><span class="h-card" translate="no"><a href="https://tech.lgbt/@snowfox" class="u-url mention">@<span>snowfox</span></a></span> <span class="h-card" translate="no"><a href="https://mastodon.social/@whitequark" class="u-url mention">@<span>whitequark</span></a></span> Since PSHUFB returns 0 when the MSB is set, you can chain them with XORs to get larger LUTs (in 16B increments) if you&#39;re OK with the LUT itself being a bit funny. Specifically:</p><p> vpshufb out, lut0, index</p><p> vpsubb index, index, sixteen<br /> vpshufb temp, lut1, index<br /> vpxor out, out, temp</p><p> vpsubb index, index, sixteen<br /> vpshufb temp, lut2, index<br /> vpxor out, out, temp</p><p>init:<br /> lut0 = tab[0:16]<br /> lut1 = tab[16:32] ^ lut0<br /> lut2 = tab[32:48] ^ lut1</p><p>and so forth</p>

<p><span class="h-card" translate="no"><a href="https://mastodon.gamedev.place/@rygorous" class="u-url mention">@<span>rygorous</span></a></span> thanks!</p>

<p><span class="h-card" translate="no"><a href="https://mastodon.social/@whitequark" class="u-url mention">@<span>whitequark</span></a></span> For tables in immediate operands, the main ones are AVX512+.</p><p>VPTERNLOGD has a 8-bit truth table of its 3 inputs as imm8.</p><p>VFIXUPIMM[SP][DS] has a 32-bit LUT embedded as imm32 that says how to treat various float special values</p><p>There&#39;s a weird secondary opcode byte (not really a LUT) as imm8 for PCMP[EI]STR[IM] (SSE4.2).</p>

<p><span class="h-card" translate="no"><a href="https://mastodon.social/@whitequark" class="u-url mention">@<span>whitequark</span></a></span> <span class="h-card" translate="no"><a href="https://mastodon.social/@dougall" class="u-url mention">@<span>dougall</span></a></span> <span class="h-card" translate="no"><a href="https://mastodon.gamedev.place/@rygorous" class="u-url mention">@<span>rygorous</span></a></span> Yes, ternlogop and fixup are the main ones. There were a few other fixup-like instructions added later I think?</p>

<p>Now I know how my elders felt about the fact that my fellow millennials and I never answered the phone.</p>

<p>Part of the boomer effect with respect to technology comes from shifts in what&#39;s considered basic communication infrastructure over time. For my generation it&#39;s email and SMS. For an older generation it was phone calls and letters. I&#39;ve been putting more effort into getting to know people in my area recently, and it is *so* painful: everything is Instagram, Discord, and Twitter (yes really, Twitter, still!). I feel like a dinosaur. Most people wont even respond to emails.</p>

<p>We&#39;ve sailed off the anchor on a starboard tack with sails set up to the t&#39;gallants and braced with a big fan.</p>

<p><span class="h-card" translate="no"><a href="https://mastodon.online/@tealeg" class="u-url mention">@<span>tealeg</span></a></span> <span class="h-card" translate="no"><a href="https://cyberplace.social/@GossiTheDog" class="u-url mention">@<span>GossiTheDog</span></a></span> Yep, saw and shared this on bsky…</p>