diff --git a/src/de/inetsoftware/jwebassembly/module/ModuleWriter.java b/src/de/inetsoftware/jwebassembly/module/ModuleWriter.java
index cc5daee..da35e55 100644
--- a/src/de/inetsoftware/jwebassembly/module/ModuleWriter.java
+++ b/src/de/inetsoftware/jwebassembly/module/ModuleWriter.java
@@ -395,6 +395,13 @@ public abstract class ModuleWriter implements Closeable {
                     case 114: // frem
                     case 115: // drem
                         throw new WasmException( "Modulo/Remainder for floating numbers is not supported in WASM. Use int or long data types." + op, sourceFile, lineNumber );
+                    case 132: // iinc
+                        int idx = byteCode.readUnsignedByte();
+                        writeLoadStore( true, ValueType.i32, idx );
+                        writeConstInt( byteCode.readUnsignedByte() );
+                        writeNumericOperator( NumericOperator.add, ValueType.i32);
+                        writeLoadStore( false, ValueType.i32, idx );
+                        break;
                     case 136: // l2i
                         writeCast( ValueTypeConvertion.l2i );
                         break;
diff --git a/test/de/inetsoftware/jwebassembly/math/MathOperations.java b/test/de/inetsoftware/jwebassembly/math/MathOperations.java
index 42820ef..8d06bbe 100644
--- a/test/de/inetsoftware/jwebassembly/math/MathOperations.java
+++ b/test/de/inetsoftware/jwebassembly/math/MathOperations.java
@@ -99,6 +99,7 @@ public class MathOperations {
 
         @Export
         static int addInt( int a, int b ) {
+            b++;
             return a + b;
         }
 
@@ -126,8 +127,9 @@ public class MathOperations {
 
         @Export
         static int subLong() {
-            long a = 1L;
+            long a = -1L;
             long b = 3L;
+            a--;
             return (int)(a - b);
         }