diff --git a/ethereumj-core/src/main/java/org/ethereum/vm/DataWord.java b/ethereumj-core/src/main/java/org/ethereum/vm/DataWord.java
index e900674c..ab2ad40d 100644
--- a/ethereumj-core/src/main/java/org/ethereum/vm/DataWord.java
+++ b/ethereumj-core/src/main/java/org/ethereum/vm/DataWord.java
@@ -227,7 +227,6 @@ public class DataWord implements Comparable<DataWord> {
         this.data = ByteUtil.copyToArray(result.and(MAX_VALUE));
     }
 
-    // TODO: improve with no BigInteger
     public void sMod(DataWord word) {
 
         if (word.isZero()) {
@@ -239,6 +238,17 @@ public class DataWord implements Comparable<DataWord> {
         this.data = ByteUtil.copyToArray(result.and(MAX_VALUE));
     }
     
+    public void addmod(DataWord word1, DataWord word2) {
+		this.add(word1);
+		BigInteger result = this.value().mod(word2.value());
+        this.data = ByteUtil.copyToArray(result.and(MAX_VALUE));
+    }
+    
+    public void mulmod(DataWord word1, DataWord word2) {
+		BigInteger result = value().multiply(word1.value()).mod(word2.value());
+        this.data = ByteUtil.copyToArray(result.and(MAX_VALUE));
+    }
+    
     public String toString() {
         return Hex.toHexString(data);
     }
diff --git a/ethereumj-core/src/main/java/org/ethereum/vm/VM.java b/ethereumj-core/src/main/java/org/ethereum/vm/VM.java
index d772a3b4..a11dae9b 100644
--- a/ethereumj-core/src/main/java/org/ethereum/vm/VM.java
+++ b/ethereumj-core/src/main/java/org/ethereum/vm/VM.java
@@ -476,16 +476,18 @@ public class VM {
 				case ADDMOD:{
                 	program.stackRequire(3);
                 	DataWord word1 = program.stackPop();
-                	word1.add(program.stackPop());
-                	word1.mod(program.stackPop());
+                	DataWord word2 = program.stackPop();
+                	DataWord word3 = program.stackPop();
+                	word1.addmod(word2, word3);
                 	program.stackPush(word1);
                 	program.step();
 				}	break;
 				case MULMOD:{
                 	program.stackRequire(3);
                 	DataWord word1 = program.stackPop();
-                	word1.mul(program.stackPop());
-                	word1.mod(program.stackPop());
+                	DataWord word2 = program.stackPop();
+                	DataWord word3 = program.stackPop();
+                	word1.mulmod(word2, word3);
                 	program.stackPush(word1);
                 	program.step();
 				}	break;