revert to smaller boom config and support in ci

.circleci/do-rtl-build.sh

@@ -1,6 +1,8 @@
 #!/bin/bash
 
-# create the different verilator builds arg (subproject)
+# create the different verilator builds
+# 1st argument is the subproject
+# 2nd argument is the config (can be unspecified)
 
 # turn echo on and error on earliest command
 set -ex
@@ -12,6 +14,18 @@ cd $HOME/project
 # enter the verisim directory and build the specific config
 cd sims/verisim
 make clean
-make SUB_PROJECT=$1 JAVA_ARGS="-Xmx2G -Xss8M"
+
+# run the particular build command
+if [ $# -ne 0 ]; then
+  if [ $# -eq 1 ]; then
+    make SUB_PROJECT=$1 JAVA_ARGS="-Xmx2G -Xss8M"
+  elif [ $# -eq 2 ]; then
+    make SUB_PROJECT=$1 CONFIG=$2 JAVA_ARGS="-Xmx2G -Xss8M"
+  else
+    exit 1 # wrong amount of args
+  fi
+else
+  exit 1 # need to provide at least the arg
+fi
 
 rm -rf ../../project