diff --git a/src/lib.rs b/src/lib.rs
index 3df8733..cccc1ca 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -16,5 +16,8 @@ pub mod lang;
 // entrypoint
 pub mod entry;
 
+// page table
+pub mod mm;
+
 // logging
 pub mod logging;
diff --git a/src/mm/addr.rs b/src/mm/addr.rs
new file mode 100644
index 0000000..a892af3
--- /dev/null
+++ b/src/mm/addr.rs
@@ -0,0 +1,223 @@
+use core::fmt::{Debug, Formatter, LowerHex, Result, UpperHex};
+use core::hash::Hash;
+use core::ops::{Add, AddAssign, Sub, SubAssign};
+
+#[inline(always)]
+fn align_up(addr: usize, align: usize) -> usize {
+    (addr + align - 1) & !(align - 1)
+}
+
+#[inline(always)]
+fn align_down(addr: usize, align: usize) -> usize {
+    addr & !(align - 1)
+}
+
+pub struct PhysAddr(pub usize);
+
+pub struct VirtAddr(pub usize);
+
+pub trait AddressOps {
+    fn as_u32(&self) -> u32;
+    fn as_u64(&self) -> u64;
+    fn as_usize(&self) -> usize;
+    fn align_up<T>(&self, align: T) -> Self
+    where
+        T: Into<usize>;
+    fn align_down<T>(&self, align: T) -> Self
+    where
+        T: Into<usize>;
+    fn is_aligned<T>(&self, align: T) -> bool
+    where
+        T: Into<usize> + Copy,
+    {
+        if align.into().is_power_of_two() {
+            self.as_usize() & (align.into() - 1) == 0
+        } else {
+            false
+        }
+    }
+}
+
+impl AddressOps for PhysAddr {
+    fn as_u32(&self) -> u32 {
+        self.0 as u32
+    }
+
+    fn as_u64(&self) -> u64 {
+        self.0 as u64
+    }
+
+    fn as_usize(&self) -> usize {
+        self.0
+    }
+
+    fn align_up<T>(&self, align: T) -> Self
+    where
+        T: Into<usize>,
+    {
+        PhysAddr(align_up(self.0, align.into()))
+    }
+
+    fn align_down<T>(&self, align: T) -> Self
+    where
+        T: Into<usize>,
+    {
+        PhysAddr(align_down(self.0, align.into()))
+    }
+}
+
+impl AddressOps for VirtAddr {
+    fn as_u32(&self) -> u32 {
+        self.0 as u32
+    }
+
+    fn as_u64(&self) -> u64 {
+        self.0 as u64
+    }
+
+    fn as_usize(&self) -> usize {
+        self.0
+    }
+
+    fn align_up<T>(&self, align: T) -> Self
+    where
+        T: Into<usize>,
+    {
+        VirtAddr(align_up(self.0, align.into()))
+    }
+
+    fn align_down<T>(&self, align: T) -> Self
+    where
+        T: Into<usize>,
+    {
+        VirtAddr(align_down(self.0, align.into()))
+    }
+}
+
+impl Add<usize> for PhysAddr {
+    type Output = Self;
+
+    fn add(self, rhs: usize) -> Self::Output {
+        Self(self.0 + rhs)
+    }
+}
+
+impl AddAssign<usize> for PhysAddr {
+    fn add_assign(&mut self, rhs: usize) {
+        *self = PhysAddr::from(self.0 + rhs);
+    }
+}
+
+impl Sub<usize> for PhysAddr {
+    type Output = PhysAddr;
+
+    fn sub(self, rhs: usize) -> Self::Output {
+        PhysAddr(self.0 - rhs)
+    }
+}
+
+impl SubAssign<usize> for PhysAddr {
+    fn sub_assign(&mut self, rhs: usize) {
+        *self = PhysAddr::from(self.0 - rhs);
+    }
+}
+
+impl Add<usize> for VirtAddr {
+    type Output = Self;
+
+    fn add(self, rhs: usize) -> Self::Output {
+        Self(self.0 + rhs)
+    }
+}
+
+impl AddAssign<usize> for VirtAddr {
+    fn add_assign(&mut self, rhs: usize) {
+        *self = VirtAddr::from(self.0 + rhs);
+    }
+}
+
+impl Sub<usize> for VirtAddr {
+    type Output = VirtAddr;
+
+    fn sub(self, rhs: usize) -> Self::Output {
+        VirtAddr(self.0 - rhs)
+    }
+}
+
+impl SubAssign<usize> for VirtAddr {
+    fn sub_assign(&mut self, rhs: usize) {
+        *self = VirtAddr::from(self.0 - rhs);
+    }
+}
+
+impl From<usize> for PhysAddr {
+    fn from(addr: usize) -> Self {
+        PhysAddr(addr)
+    }
+}
+
+impl From<PhysAddr> for usize {
+    fn from(addr: PhysAddr) -> Self {
+        addr.0
+    }
+}
+
+impl From<usize> for VirtAddr {
+    fn from(addr: usize) -> Self {
+        VirtAddr(addr)
+    }
+}
+
+impl From<VirtAddr> for usize {
+    fn from(addr: VirtAddr) -> Self {
+        addr.0
+    }
+}
+
+impl Debug for PhysAddr {
+    fn fmt(&self, f: &mut Formatter) -> Result {
+        write!(f, "PhysAddr({:#x})", self.0)
+    }
+}
+
+impl LowerHex for PhysAddr {
+    fn fmt(&self, f: &mut Formatter) -> Result {
+        write!(f, "{:#x}", self.0)
+    }
+}
+
+impl UpperHex for PhysAddr {
+    fn fmt(&self, f: &mut Formatter) -> Result {
+        write!(f, "{:#X}", self.0)
+    }
+}
+
+impl Debug for VirtAddr {
+    fn fmt(&self, f: &mut Formatter) -> Result {
+        write!(f, "VirtAddr({:#x})", self.0)
+    }
+}
+
+impl LowerHex for VirtAddr {
+    fn fmt(&self, f: &mut Formatter) -> Result {
+        write!(f, "{:#x}", self.0)
+    }
+}
+
+impl UpperHex for VirtAddr {
+    fn fmt(&self, f: &mut Formatter) -> Result {
+        write!(f, "{:#X}", self.0)
+    }
+}
+
+impl Hash for PhysAddr {
+    fn hash<H: core::hash::Hasher>(&self, state: &mut H) {
+        self.0.hash(state);
+    }
+}
+
+impl Hash for VirtAddr {
+    fn hash<H: core::hash::Hasher>(&self, state: &mut H) {
+        self.0.hash(state);
+    }
+}
diff --git a/src/mm/mod.rs b/src/mm/mod.rs
new file mode 100644
index 0000000..9f3b826
--- /dev/null
+++ b/src/mm/mod.rs
@@ -0,0 +1 @@
+pub mod addr;