1 files changed, 5 insertions, 2 deletions
diff --git a/bytecode/src/heap.rs b/bytecode/src/heap.rs
index 970db7d..f195613 100644
--- a/bytecode/src/heap.rs
+++ b/bytecode/src/heap.rs
@@ -132,11 +132,14 @@ impl Heap {
         Ok(Value(self.buf[p]))
     }
 
-    pub fn poke(&mut self, p: usize, val: Value) -> Result<(), Box<dyn Error>> {
+    pub fn poke(&mut self, p: usize, off: usize, val: Value) -> Result<(), Box<dyn Error>> {
         if p >= self.buf.len() {
             return Err(Box::from("poke: out of range"));
         }
-        self.buf[p] = val.repr();
+        if off >= self.alloc_size(p) {
+            return Err(Box::from("poke: out of range"));
+        }
+        self.buf[p + off] = val.repr();
         Ok(())
     }
 }