diff --git a/src/vm/Bytecode.java b/src/vm/Bytecode.java
index f9f760d..c5d5c12 100644
--- a/src/vm/Bytecode.java
+++ b/src/vm/Bytecode.java
@@ -36,7 +36,6 @@ public Instruction(String name, int nargs) {
 		new Instruction("imul"),
 		new Instruction("ilt"),
 		new Instruction("ieq"),
-		new Instruction("ret"),
 		new Instruction("br", 1),
 		new Instruction("brt", 1),
 		new Instruction("brf", 1),
diff --git a/src/vm/Test.java b/src/vm/Test.java
index 6549430..fdfb4db 100644
--- a/src/vm/Test.java
+++ b/src/vm/Test.java
@@ -12,7 +12,9 @@
 
 public class Test {
 	static int[] hello = {
-		ICONST, 1234,
+		ICONST, 1,
+		ICONST, 2,
+		IADD,
 		PRINT,
 		HALT
 	};
@@ -44,6 +46,7 @@ public class Test {
 
 	public static void main(String[] args) {
 		VM vm = new VM(hello, 0, 0);
+		vm.trace = true;
 		vm.exec();
 
 		vm = new VM(loop, 0, 2);
diff --git a/src/vm/VM.java b/src/vm/VM.java
index bf75f1b..4330603 100644
--- a/src/vm/VM.java
+++ b/src/vm/VM.java
@@ -57,7 +57,7 @@ protected void cpu() {
 		int opcode = code[ip];
 		int a,b,addr,offset;
 		while (opcode!= HALT && ip < code.length) {
-			if ( trace ) System.out.printf("%-35s", disInstr());
+			if ( trace ) System.err.printf("%-35s", disInstr());
 			ip++; //jump to next instruction or to operand
 			switch (opcode) {
 				case IADD:
@@ -124,11 +124,11 @@ protected void cpu() {
 				default :
 					throw new Error("invalid opcode: "+opcode+" at ip="+(ip-1));
 			}
-			if ( trace ) System.out.println(stackString());
+			if ( trace ) System.err.println(stackString());
 			opcode = code[ip];
 		}
-		if ( trace ) System.out.printf("%-35s", disInstr());
-		if ( trace ) System.out.println(stackString());
+		if ( trace ) System.err.printf("%-35s", disInstr());
+		if ( trace ) System.err.println(stackString());
 		if ( trace ) dumpDataMemory();
 	}
 
@@ -165,12 +165,12 @@ protected String disInstr() {
 	}
 
 	protected void dumpDataMemory() {
-		System.out.println("Data memory:");
+		System.err.println("Data memory:");
 		int addr = 0;
 		for (int o : globals) {
-			System.out.printf("%04d: %s\n", addr, o);
+			System.err.printf("%04d: %s\n", addr, o);
 			addr++;
 		}
-		System.out.println();
+		System.err.println();
 	}
 }