diff --git a/hbasm/src/macros.rs b/hbasm/src/macros.rs
index d041ab201..0a3c93b64 100644
--- a/hbasm/src/macros.rs
+++ b/hbasm/src/macros.rs
@@ -66,7 +66,6 @@ macro_rules! impl_asm {
     };
 }
 
-
 pub(super) use {impl_asm, impl_asm_opcodes};
 
 #[allow(clippy::single_component_path_imports)]
diff --git a/hbvm/src/vm/mem/mod.rs b/hbvm/src/vm/mem/mod.rs
index dd92875b9..65f580012 100644
--- a/hbvm/src/vm/mem/mod.rs
+++ b/hbvm/src/vm/mem/mod.rs
@@ -2,11 +2,13 @@
 
 pub mod paging;
 
-use self::paging::{PageTable, Permission, PtEntry};
-use super::{trap::HandleTrap, VmRunError};
-use alloc::boxed::Box;
-use core::mem::MaybeUninit;
-use derive_more::Display;
+use {
+    self::paging::{PageTable, Permission, PtEntry},
+    super::{trap::HandleTrap, VmRunError},
+    alloc::boxed::Box,
+    core::mem::MaybeUninit,
+    derive_more::Display,
+};
 
 /// HoleyBytes virtual memory
 #[derive(Clone, Debug)]
diff --git a/hbvm/src/vm/mem/paging.rs b/hbvm/src/vm/mem/paging.rs
index b1979ebbd..c621ab4b1 100644
--- a/hbvm/src/vm/mem/paging.rs
+++ b/hbvm/src/vm/mem/paging.rs
@@ -1,12 +1,14 @@
 //! Page table and associated structures implementation
 
-use core::{
-    fmt::Debug,
-    mem::MaybeUninit,
-    ops::{Index, IndexMut},
-    slice::SliceIndex,
+use {
+    core::{
+        fmt::Debug,
+        mem::MaybeUninit,
+        ops::{Index, IndexMut},
+        slice::SliceIndex,
+    },
+    delegate::delegate,
 };
-use delegate::delegate;
 
 /// Page entry permission
 #[derive(Clone, Copy, Debug, Default, PartialEq, Eq)]
@@ -30,7 +32,7 @@ pub enum Permission {
 pub struct PtEntry(u64);
 impl PtEntry {
     /// Create new
-    /// 
+    ///
     /// # Safety
     /// - `ptr` has to point to valid data and shall not be deallocated
     ///    troughout the entry lifetime
@@ -61,7 +63,6 @@ impl Debug for PtEntry {
     }
 }
 
-
 /// Page table
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
 #[repr(align(4096))]
@@ -145,7 +146,7 @@ impl Default for PageTable {
 #[repr(C, align(4096))]
 pub union PtPointedData {
     /// Node - next page table
-    pub pt: PageTable,
+    pub pt:   PageTable,
     /// Leaf
     pub page: u8,
 }
diff --git a/hbvm/src/vm/mod.rs b/hbvm/src/vm/mod.rs
index 0f6fa2f0d..8b975bfff 100644
--- a/hbvm/src/vm/mod.rs
+++ b/hbvm/src/vm/mod.rs
@@ -97,6 +97,10 @@ pub struct Vm<'a, T> {
 
     /// Program
     program: &'a [u8],
+
+    pub last_tick_count: u32,
+    pub tick_callback: Option<fn() -> u32>,
+    pub tick_limit: u32,
 }
 
 impl<'a, T: HandleTrap> Vm<'a, T> {
@@ -111,6 +115,9 @@ impl<'a, T: HandleTrap> Vm<'a, T> {
             traph,
             pc: 0,
             program,
+            last_tick_count: 0,
+            tick_callback: None,
+            tick_limit: 32,
         }
     }
 
@@ -123,12 +130,12 @@ impl<'a, T: HandleTrap> Vm<'a, T> {
     /// Execute program
     ///
     /// Program can return [`VmRunError`] if a trap handling failed
-    pub fn run(&mut self) -> Result<(), VmRunError> {
+    pub fn run(&mut self) -> Result<u32, VmRunError> {
         use hbbytecode::opcode::*;
         loop {
             // Fetch instruction
             let Some(&opcode) = self.program.get(self.pc)
-                else { return Ok(()) };
+                else { return Ok(2) };
 
             // Big match
             unsafe {
@@ -318,7 +325,15 @@ impl<'a, T: HandleTrap> Vm<'a, T> {
                     }
                 }
             }
+            if self.tick_callback.is_some() {
+                let ret = self.tick_callback.unwrap()();
+                if (ret - self.last_tick_count) >= self.tick_limit {
+                    return Ok(0);
+                }
+            }
+            return Ok(1);
         }
+        
     }
 
     /// Read register