diff --git a/src/hulk/acpi.d b/src/hulk/acpi.d
index c893a03..1dad759 100644
--- a/src/hulk/acpi.d
+++ b/src/hulk/acpi.d
@@ -15,14 +15,13 @@ struct Acpi
      */
     private static __gshared List!Header tables;
 
-    enum uint APIC_SIGNATURE = signature("APIC");
     enum uint MCFG_SIGNATURE = signature("MCFG");
     enum uint XSDT_SIGNATURE = signature("XSDT");
 
     /**
      * ACPI table header structure.
      */
-    static struct Header
+    public static struct Header
     {
         uint signature;
         uint length;
@@ -46,37 +45,6 @@ struct Acpi
     }
     static assert(XSDT.tables.offsetof == 36);
 
-    static struct MADT
-    {
-        static struct Entry
-        {
-            enum LOCAL_APIC_ADDRESS_OVERRIDE = 5;
-
-            ubyte type;
-            ubyte length;
-        }
-
-        Header header;
-        uint local_apic_address;
-        uint flags;
-
-        void initialize()
-        {
-            apic_address = local_apic_address;
-            const(void) * end = cast(const(void) *)(&this) + header.length;
-            const(Entry) * entry = cast(const(Entry) *)(cast(ulong)&this + MADT.sizeof);
-            while (entry < end)
-            {
-                entry = cast(const(Entry) *)(cast(size_t)entry + entry.length);
-                if (entry.type == Entry.LOCAL_APIC_ADDRESS_OVERRIDE)
-                {
-                    /* Found a 64-bit Local APIC Address Override entry. */
-                    memcpy(cast(void *)&apic_address, cast(const(void) *)entry + 4u, apic_address.sizeof);
-                }
-            }
-        }
-    }
-
     static struct MCFG
     {
         /* PCI Segment Group Memory Area Descriptor. */
@@ -106,10 +74,6 @@ struct Acpi
         }
     }
 
-    public __gshared ulong apic_address;
-
-    public __gshared MADT * madt;
-
     public __gshared MCFG * mcfg;
 
     public static void initialize(ulong acpi_xsdt_phys)
@@ -148,20 +112,11 @@ struct Acpi
                     (signature >> 16u) & 0xFFu,
                     (signature >> 24u) & 0xFFu,
                     address);
-            if (signature == APIC_SIGNATURE)
-            {
-                madt = cast(MADT *)address;
-                madt.initialize();
-            }
-            else if (signature == MCFG_SIGNATURE)
+            if (signature == MCFG_SIGNATURE)
             {
                 mcfg = cast(MCFG *)address;
             }
         }
-        if (madt == null)
-        {
-            Klog.fatal_error("MADT table not found");
-        }
         if (mcfg == null)
         {
             Klog.fatal_error("MCFG table not found");
@@ -174,14 +129,14 @@ struct Acpi
      * @param name
      *   Table name.
      */
-    public Header * get_table(string name)
+    public static Header * get_table(string name)
     {
         uint signature = signature(name);
         foreach (table; tables)
         {
             if (table.signature == signature)
             {
-                return &table;
+                return table;
             }
         }
         Klog.fatal_error("Could not find requested ACPI table");
diff --git a/src/hulk/apic.d b/src/hulk/apic.d
index 2fa25e0..e0a7947 100644
--- a/src/hulk/apic.d
+++ b/src/hulk/apic.d
@@ -9,6 +9,7 @@ import hulk.idt;
 import hulk.rtc;
 import hulk.pit;
 import hulk.klog;
+import hulk.memory;
 
 struct Apic
 {
@@ -17,6 +18,49 @@ struct Apic
     private enum ulong IRQ_PIT = 2u;
     private enum ulong IRQ_RTC = 8u;
 
+    /**
+     * MADT ACPI table structure.
+     */
+    static struct MADT
+    {
+        /**
+         * MADT table entry header.
+         */
+        static struct Entry
+        {
+            enum LOCAL_APIC_ADDRESS_OVERRIDE = 5;
+
+            ubyte type;
+            ubyte length;
+        }
+
+        Acpi.Header header;
+        uint local_apic_address;
+        uint flags;
+
+        /**
+         * Scan the MADT table.
+         */
+        public void scan()
+        {
+            apic_registers = cast(ApicRegisters *)local_apic_address;
+            const(void) * end = cast(const(void) *)(&this) + header.length;
+            const(Entry) * entry = cast(const(Entry) *)(cast(ulong)&this + MADT.sizeof);
+            while (entry < end)
+            {
+                entry = cast(const(Entry) *)(cast(size_t)entry + entry.length);
+                if (entry.type == Entry.LOCAL_APIC_ADDRESS_OVERRIDE)
+                {
+                    /* Found a 64-bit Local APIC Address Override entry. */
+                    memcpy(cast(void *)&apic_registers, cast(const(void) *)entry + 4u, apic_registers.sizeof);
+                }
+            }
+        }
+    }
+
+    /**
+     * APIC register structure.
+     */
     static struct ApicRegister
     {
         public uint value;
@@ -25,6 +69,9 @@ struct Apic
         private ubyte[12] _padding;
     }
 
+    /**
+     * APIC registers.
+     */
     static struct ApicRegisters
     {
         ApicRegister[2] _reserved0;
@@ -57,6 +104,9 @@ struct Apic
         ApicRegister divide_configuration;
     }
 
+    /**
+     * I/O APIC registers.
+     */
     static struct IoApicRegisters
     {
         ApicRegister address;
@@ -66,10 +116,17 @@ struct Apic
     private static __gshared ApicRegisters * apic_registers;
     private static __gshared IoApicRegisters * io_apic_registers;
 
+    /**
+     * Initialize APIC.
+     */
     public static void initialize()
     {
-        apic_registers = cast(ApicRegisters *)Acpi.apic_address;
+        Klog.writefln("\a3Initializing APIC");
         io_apic_registers = cast(IoApicRegisters *)0xFEC0_0000u;
+        MADT * madt = cast(MADT *)Acpi.get_table("APIC");
+        madt.scan();
+        Klog.writefln("APIC found at %p", apic_registers);
+        Klog.writefln("I/O APIC found at %p", io_apic_registers);
         Hurl.map(cast(ulong)apic_registers, cast(ulong)apic_registers,
                 PT_WRITABLE | PT_WRITE_THROUGH | PT_DISABLE_CACHE | PT_NO_EXECUTE);
         Hurl.map(cast(ulong)io_apic_registers, cast(ulong)io_apic_registers,
@@ -86,6 +143,9 @@ struct Apic
         configure_io_apic_irq(IRQ_RTC, Idt.INT_APIC_BASE + IRQ_RTC);
     }
 
+    /**
+     * Configure routing for an I/O APIC IRQ.
+     */
     private static void configure_io_apic_irq(size_t io_apic_irq, size_t interrupt_id)
     {
         ulong entry = interrupt_id;
@@ -95,11 +155,17 @@ struct Apic
         io_apic_registers.data.value = entry >> 32u;
     }
 
+    /**
+     * Signal APIC end of interrupt.
+     */
     public static void eoi()
     {
         apic_registers.eoi.value = 0u;
     }
 
+    /**
+     * APIC interrupt handler.
+     */
     public static void isr(ulong vector)
     {
         switch (vector)
diff --git a/src/hulk/list.d b/src/hulk/list.d
index f9f9879..e3777c1 100644
--- a/src/hulk/list.d
+++ b/src/hulk/list.d
@@ -34,12 +34,12 @@ struct List(T)
     /**
      * Allow foreach iteration across a List.
      */
-    public int opApply(scope int delegate(ref T) dg)
+    public int opApply(scope int delegate(T *) dg)
     {
         List!T * entry = &this;
         while (entry.next != null)
         {
-            int result = dg(*entry.item);
+            int result = dg(entry.item);
             if (result != 0)
             {
                 return result;
diff --git a/src/hulk/usb/usb.d b/src/hulk/usb/usb.d
index 1528911..95c9ec4 100644
--- a/src/hulk/usb/usb.d
+++ b/src/hulk/usb/usb.d
@@ -17,7 +17,7 @@ struct Usb
         {
             if (pci_device.type == Pci.XHCI_CONTROLLER)
             {
-                XHCI.build(&pci_device);
+                XHCI.build(pci_device);
             }
         }
     }