Icestorm and yosys are cool!<p>Since then even more CPUs are working on ICE40:<p><a href="https:&#x2F;&#x2F;github.com&#x2F;cliffordwolf&#x2F;picorv32" rel="nofollow">https:&#x2F;&#x2F;github.com&#x2F;cliffordwolf&#x2F;picorv32</a><p>Or a really small and slow one (smaller than J1, but needs more RAM): <a href="https:&#x2F;&#x2F;github.com&#x2F;combinatorylogic&#x2F;soc&#x2F;tree&#x2F;master&#x2F;backends&#x2F;tiny1" rel="nofollow">https:&#x2F;&#x2F;github.com&#x2F;combinatorylogic&#x2F;soc&#x2F;tree&#x2F;master&#x2F;backends...</a>