diff --git a/src/arch/x86_64/driver/acpi/mod.rs b/src/arch/x86_64/driver/acpi/mod.rs
index b286501..6e0e313 100644
--- a/src/arch/x86_64/driver/acpi/mod.rs
+++ b/src/arch/x86_64/driver/acpi/mod.rs
@@ -42,20 +42,35 @@ pub fn init() -> Result<(), ACPI_Error> {
 		return Err(ACPI_Error::NotMapped);
 	}
 	let rsdt = unsafe{ &*(rsdp.RsdtPhysicalAddress as *const rsdt) };
-	let entry_count = (rsdt.Header.Length as usize - size_of::<header>()) / 4;
 	let mut madt: Option<&'static madt> = None;
-	for i in 0 ..  entry_count {
-		let entry = unsafe{ rsdt.entry_at(i) };
+	for i in 0 .. rsdt.entry_count() {
+		let entry = rsdt.entry_at(i);
 		if entry > PHYSICAL_MEMORY_LIMIT {
 			return Err(ACPI_Error::NotMapped);
 		}
 		let header = unsafe{ &*(entry as *const header) };
-		debug!("{:?}", header);
+		// debug!("{:?}", header);
 		if &header.Signature == b"APIC" {
 			madt = Some(unsafe{ &*(entry as *const madt) });
 		}
 	}
 	debug!("{:?}", madt);
-	// return acpi_config_smp(madt);
+	config_smp(madt.expect("acpi: madt not found."));
 	Ok(())
 }
+
+fn config_smp(madt: &'static madt) {
+	let lapic_addr = madt.LapicAddress;
+
+	for entry in madt.entry_iter() {
+		debug!("{:?}", entry);
+		match &entry {
+			&MadtEntry::LocalApic(ref lapic) => {},
+			&MadtEntry::IoApic(ref ioapic) => {
+			},
+			_ => {},
+		}
+	}
+	// TODO
+	unimplemented!();
+}
\ No newline at end of file
diff --git a/src/arch/x86_64/driver/acpi/structs.rs b/src/arch/x86_64/driver/acpi/structs.rs
index 51dd777..0ec80cf 100644
--- a/src/arch/x86_64/driver/acpi/structs.rs
+++ b/src/arch/x86_64/driver/acpi/structs.rs
@@ -2,6 +2,7 @@
 // Copy from crate 'acpica-sys'
 
 use util::{Checkable, bytes_sum};
+use core::mem::size_of;
 
 #[repr(C)]
 #[derive(Debug)]
@@ -45,8 +46,15 @@ pub struct rsdt {
 }
 
 impl rsdt {
-    pub unsafe fn entry_at(&self, id: usize) -> u32 {
-        *(self.TableOffsetEntry.as_ptr().offset(id as isize))
+    pub fn entry_count(&self) -> usize {
+        (self.Header.Length as usize - size_of::<Self>()) / 4
+    }
+    pub fn entry_at(&self, id: usize) -> u32 {
+        assert!(id < self.entry_count());
+        unsafe {
+            let p = (self as *const Self).offset(1) as *const u32;
+            *(p.offset(id as isize))
+        }
     }
 }
 
@@ -54,34 +62,80 @@ impl rsdt {
 #[derive(Debug)]
 pub struct madt {
     pub Header: header,
-    pub Address: u32,
+    pub LapicAddress: u32,
     pub Flags: u32,
     Table: [u32; 0],
 }
 
 impl Checkable for madt {
     fn check(&self) -> bool {
-        &self.Header.Signature == b"APIC"
+        &self.Header.Signature == b"APIC" && self.Header.Length >= size_of::<Self>() as u32
     }
 }
 
-#[repr(C)]
 #[derive(Debug)]
-pub struct madt_local_apic {
-	pub Type: u8,
+pub enum MadtEntry {
+    Unknown(MadtEntry_Unknown),
+    LocalApic(MadtEntry_LocalApic),
+    IoApic(MadtEntry_IoApic),
+}
+#[repr(C)]
+#[derive(Debug, Clone)]
+pub struct MadtEntry_Unknown {
+    pub Type: u8,
+    pub Length: u8,
+}
+#[repr(C)]
+#[derive(Debug, Clone)]
+pub struct MadtEntry_LocalApic {
+    pub Type: u8,   // 0
     pub Length: u8,
     pub ProcessorId: u8,
     pub Id: u8,
     pub LapicFlags: u32,
 }
-
 #[repr(C)]
-#[derive(Debug)]
-pub struct madt_io_apic {
-    pub Type: u8,
+#[derive(Debug, Clone)]
+pub struct MadtEntry_IoApic {
+    pub Type: u8,   // 1
     pub Length: u8,
     pub Id: u8,
     pub Reserved: u8,
     pub Address: u32,
     pub GlobalIrqBase: u32,
+}
+
+#[derive(Debug)]
+pub struct MadtEntryIter<'a> {
+    madt: &'a madt,
+    ptr: *const u8,
+    end_ptr: *const u8,
+}
+
+impl madt {
+    pub fn entry_iter(&self) -> MadtEntryIter {
+        let ptr = unsafe{ (self as *const Self).offset(1) } as *const u8;
+        let end_ptr = unsafe{ ptr.offset(self.Header.Length as isize) };
+        MadtEntryIter { madt: self, ptr, end_ptr }
+    }
+}
+
+impl<'a> Iterator for MadtEntryIter<'a> {
+    type Item = MadtEntry;
+    fn next(&mut self) -> Option<Self::Item> {
+        if self.ptr >= self.end_ptr {
+            return None;
+        }
+        unsafe {
+            let typeId = *self.ptr.offset(0);
+            let len = *self.ptr.offset(1);
+            let ret = Some(match typeId {
+                0 => MadtEntry::LocalApic( (&*(self.ptr as *const MadtEntry_LocalApic)).clone() ),
+                1 => MadtEntry::IoApic( (&*(self.ptr as *const MadtEntry_IoApic)).clone() ),
+                _ => MadtEntry::Unknown( (&*(self.ptr as *const MadtEntry_Unknown)).clone() ),
+            });        
+            self.ptr = self.ptr.offset(len as isize);
+            ret       
+        }
+    }
 }
\ No newline at end of file