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--- dev:atomic_parameters [2014/09/09 18:42] – created tsmall1
+++ dev:atomic_parameters [2014/09/21 17:54] (current) – [Make Getter and Setter] tsmall1
@@ Line 5: / Line 5: @@
 ===== Declare Compilation Constants =====
-First, we need to describe in the Element how big of a field we want to use, and where to place it inside the atom. We need to use the bits on the right hand part of the atom first, since a number of ones on the left hand side are already used. For instance, let's declare a small field storing a random byte:
+First, we need to describe in the Element how big of a field we want to use, and where to place it inside the atom. We need to use the bits on the right hand part of the atom first, since a number of ones on the left hand side are already used. For instance, let's declare a small field which can hold a byte:
 <code>
@@ Line 12: / Line 12: @@
     BITS = P::BITS_PER_ATOM,
-    RANDOM_BITS_LENGTH = 8,
+    BYTE_BITS_LENGTH = 8,
-    RANDOM_BITS_POSITION = BITS - RANDOM_BITS_LENGTH - 1
+    BYTE_BITS_POSITION = BITS - BYTE_BITS_LENGTH - 1
-}
+};
 </code>
@@ Line 20: / Line 20: @@
 <code>
-typedef BitField<BitVector<BITS>, RANDOM_BITS_LENGTH, RANDOM_BITS_POSITION> AFRandomBits;
+typedef BitField<BitVector<BITS>, BYTE_BITS_LENGTH, BYTE_BITS_POSITION> AFByteBits;
 </code>
+make sure that BitField is included in the file by adding:
+<code>
+#include "BitField.h"
+</code>
+to the top of the file.
+===== Make Getter and Setter =====
+We now need methods which access these bits. In the public section of your elemenet, place:
+<code>
+u32 GetByteBits(const T& us) const
+{
+    return AFByteBits::Read(this->GetBits(us));
+}
+void SetByteBits(T& us, u32 bits) const
+{
+    AFByteBits::Write(this->GetBits(us), bits & 0xff);
+}
+</code>
+Now we are able to Get and Set these bits.
+===== Set Default Value =====
+We should also set some sort of default value for these bits. This is done by overriding the **GetDefaultAtom()** method. Place in the public section of your element:
+<code>
+static const u32 TYPE()
+{
+    return THE_INSTANCE.GetType();
+}
+virtual const T& GetDefaultAtom() const
+{
+    static T defaultAtom(TYPE(), 0, 0, 0);
+    this->SetByteBits(defaultAtom, 0 /* Or other default value */);
+    return defaultAtom;
+}
+</code>
+In this example, the default atom has its bitfield set to 0. We can use this call during the behavior method as well to read or write bits of other atoms.