diff --git a/src/frame.rs b/src/frame.rs
index 889c0c6..884a337 100644
--- a/src/frame.rs
+++ b/src/frame.rs
@@ -1,18 +1,20 @@
-use Result;
 use stack::Stack;
+use Result;
 
 #[derive(Debug)]
 pub struct Frame {
+    pub base: usize,
     pub stack: Stack,
     pub locals: Vec<i32>,
 }
 
 impl Frame {
-    pub fn new(num_locals: usize) -> Frame {
-        if cfg!(feature="debug:frame") {
-           println!("Initializing frame of len {}", num_locals);
+    pub fn new(num_locals: usize, base: usize) -> Frame {
+        if cfg!(feature = "debug:frame") {
+            println!("Initializing frame of len {}", num_locals);
         }
         Frame {
+            base,
             stack: Stack::new(),
             locals: vec![0; num_locals],
         }
@@ -40,4 +42,4 @@ impl Frame {
         self.locals[offset] = val;
         Ok(())
     }
-}
\ No newline at end of file
+}
diff --git a/src/machine.rs b/src/machine.rs
index 7138a13..b49cb8a 100644
--- a/src/machine.rs
+++ b/src/machine.rs
@@ -41,7 +41,7 @@ impl Machine {
             halted: false,
             pool,
             block,
-            frame: vec![Frame::new(ANTI_BS_SIZE)],
+            frame: vec![Frame::new(ANTI_BS_SIZE, 0)],
             stream_in: Box::new(::std::io::stdin()),
             stream_out: Arc::new(Mutex::new(::std::io::stdout())),
 
diff --git a/src/ops.rs b/src/ops.rs
index 7ae7a33..36ad400 100644
--- a/src/ops.rs
+++ b/src/ops.rs
@@ -235,13 +235,13 @@ fn iinc(machine: &mut Machine) -> Result<()> {
 
 fn invokevirtual(machine: &mut Machine) -> Result<()> {
     let method_index = machine.block.read_u16()?;
-    let invoke_addr = machine.pool.get(method_index as usize)?;
+    let invoke_addr = machine.pool.get(method_index as usize)? as usize;
     let return_addr = machine.get_program_counter();
 
-    machine.block.seek(invoke_addr as usize)?;
+    machine.block.seek(invoke_addr)?;
     let arg_count = machine.block.read_u16()?;
     let var_count = machine.block.read_u16()?;
-    let mut newframe = Frame::new((arg_count + var_count) as usize);
+    let mut newframe = Frame::new((arg_count + var_count) as usize, invoke_addr);
 
     // Lifetime for cur_stack
     {