diff --git a/defs.h b/defs.h
index 8dff6ad..78314c8 100644
--- a/defs.h
+++ b/defs.h
@@ -10,5 +10,18 @@ constexpr uint8_t STACK_SIZE = 16;
 #endif
 
 constexpr size_t	MAX_TOKEN_LENGTH = 16;
+constexpr size_t dshift = (sizeof(KF_INT) * 8) - 1;
+
+static inline KF_INT
+mask(size_t bits)
+{
+	KF_INT m = 0;
+
+	for (size_t i = 0; i < bits; i++) {
+		m += 1 << i;
+	}
+	
+	return m;
+}
 
 #endif // __KF_DEFS_H__
\ No newline at end of file
diff --git a/doc/part-0x07.rst b/doc/part-0x07.rst
index 6aa8ff6..8fa0b8e 100644
--- a/doc/part-0x07.rst
+++ b/doc/part-0x07.rst
@@ -3,3 +3,124 @@ Write You a Forth, 0x07
 
 :date: 2018-03-01 19:31
 :tags: wyaf, forth
+
+At this point, I've finished most of the nucleus layer. All that's left to
+implement are ``EXIT``, ``I``, and ``J`` --- the first requires better
+execution support, which I'll talk about at the end. The other two, I'm not so
+sure about yet.
+
+However, I made some large changes, so let's dive in. Here's the new Linux
+definitions file::
+
+        #ifndef __KF_LINUX_DEFS_H__
+        #define __KF_LINUX_DEFS_H__
+
+        #include <stddef.h>
+        #include <stdint.h>
+
+        typedef int32_t KF_INT;
+        typedef uint32_t KF_UINT;
+        typedef int64_t	KF_LONG;
+
+        typedef uintptr_t KF_ADDR;
+        constexpr uint8_t STACK_SIZE = 128;
+        constexpr size_t ARENA_SIZE = 65535;
+
+        #endif
+
+I've also updated the main ``defs.h`` file to move some constants there::
+
+        #ifndef __KF_DEFS_H__
+        #define __KF_DEFS_H__
+
+        #ifdef __linux__
+        #include "linux/defs.h"
+        #else
+        typedef int KF_INT;
+        typedef long KF_LONG;
+        constexpr uint8_t STACK_SIZE = 16;
+        #endif
+
+        constexpr size_t	MAX_TOKEN_LENGTH = 16;
+        constexpr size_t dshift = (sizeof(KF_INT) * 8) - 1;
+
+        static inline KF_INT
+        mask(size_t bits)
+        {
+                KF_INT m = 0;
+
+                for (size_t i = 0; i < bits; i++) {
+                        m += 1 << i;
+                }
+                
+                return m;
+        }
+
+        #endif // __KF_DEFS_H__
+
+Addresses
+^^^^^^^^^
+
+The first major change is the addition of the ``KF_ADDR`` type. This is needed
+to implement the memory manipulation words. I've added some additional utility
+functions for pushing and popping addresses from the data stack; they're stored
+as double numbers::
+
+    static bool
+    pop_addr(System *sys, KF_ADDR *a)
+    {
+            KF_LONG	b;
+            if (!pop_long(sys, &b)) {
+                    // Status is already set.
+                    return false;
+            }
+
+            *a = static_cast<KF_ADDR>(b);
+            sys->status = STATUS_OK;
+            return true;
+    }
+
+    static bool
+    push_addr(System *sys, KF_ADDR a)
+    {
+            KF_LONG	b = static_cast<KF_LONG>(a);
+            if (!push_long(sys, b)) {
+                    // Status is already set.
+                    return false;
+            }
+
+            sys->status = STATUS_OK;
+            return true;
+    }
+
+Now I can actually implement ``!`` and so forth::
+
+        static bool
+        store(System *sys)
+        {
+                KF_ADDR	a = 0; // address
+                KF_INT	b = 0; // value
+                KF_LONG	c = 0; // temporary
+
+                if (!pop_long(sys, &c)) {
+                        sys->status = STATUS_STACK_UNDERFLOW;
+                        return false;
+                }
+                a = static_cast<KF_ADDR>(c);
+                
+                if (!sys->dstack.pop(&b)) {
+                        sys->status = STATUS_STACK_UNDERFLOW;
+                        return false;
+                }
+
+                *((KF_INT *)a) = b;
+                sys->status = STATUS_OK;
+                return true;
+        }
+
+There's definitely a sense of finangling here.
+
+The return stack
+^^^^^^^^^^^^^^^^
+
+The ``>R`` series of words requires a 
\ No newline at end of file
diff --git a/linux/defs.h b/linux/defs.h
index c007fee..8cec973 100644
--- a/linux/defs.h
+++ b/linux/defs.h
@@ -7,22 +7,9 @@
 typedef int32_t KF_INT;
 typedef uint32_t KF_UINT;
 typedef int64_t	KF_LONG;
-constexpr size_t dshift = (sizeof(KF_INT) * 8) - 1;
 
 typedef uintptr_t KF_ADDR;
 constexpr uint8_t STACK_SIZE = 128;
 constexpr size_t ARENA_SIZE = 65535;
 
-static inline KF_INT
-mask(size_t bits)
-{
-	KF_INT m = 0;
-
-	for (size_t i = 0; i < bits; i++) {
-		m += 1 << i;
-	}
-	
-	return m;
-}
-
 #endif
\ No newline at end of file