do not drain a port unless it is currently full

diff --git a/src/edu/berkeley/fleet/fpga/Fpga.java b/src/edu/berkeley/fleet/fpga/Fpga.java
index 6f23308..dc4e878 100644 (file)
--- a/src/edu/berkeley/fleet/fpga/Fpga.java
+++ b/src/edu/berkeley/fleet/fpga/Fpga.java
@@ -177,7 +177,7 @@ public class Fpga extends FleetTwoFleet {
                 pw.println("`define "+name+"_full    ("+name+"_r && !"+name+"_a)");
                 pw.println("`define "+name+"_empty  (!"+name+"_r && !"+name+"_a)");
                 if (dd.isInputDock()) {
-                    pw.println("`define drain_"+name+"  "+name+"_a <= 1;");
+                    pw.println("`define drain_"+name+"  if ("+name+"_r && !"+name+"_a) "+name+"_a <= 1;");
                 } else {
                     pw.println("`define fill_"+name+"  "+name+"_r <= 1;");
                 }