add open vams implementations

diff --git a/3d_gpu.mdwn b/3d_gpu.mdwn
index d7c42044553a992c36bffc8ad53b2833f99337ea..48dc4919b9bf4a8c147316c1346262929d9625cd 100644 (file)
--- a/3d_gpu.mdwn
+++ b/3d_gpu.mdwn
@@ -67,3 +67,10 @@ Progress:
 * <https://github.com/efabless/raven-picorv32> - <https://efabless.com>
 * <https://efabless.com/design_catalog/default>
 * <https://toyota-ai.ventures/>
+
+# Analog Simulation
+
+* <https://github.com/Isotel/mixedsim>
+* <http://www.vlsiacademy.org/open-source-cad-tools.html>
+* <http://ngspice.sourceforge.net/adms.html>
+* <https://en.wikipedia.org/wiki/Verilog-AMS#Open_Source_Implementations>