add some doc

androscalpel/src/instructions.rs

@@ -101,14 +101,31 @@ pub enum Instruction {
     CheckCast { reg: u8, lit: IdType },
     /// Check if an object if an instance of a type.
     /// (put 1 in the dest register if yes, else 0)
-    InstanceOf { dest: u8, obj: u8, lit: IdType },
+    InstanceOf {
+        /// 4 bits register
+        dest: u8,
+        /// 4 bits register
+        obj: u8,
+        lit: IdType,
+    },
     /// Get the number of item in an array.
     /// (put the lenght in the dest register)
-    ArrayLength { dest: u8, arr: u8 },
+    ArrayLength {
+        /// 4 bits register
+        dest: u8,
+        /// 4 bits register
+        arr: u8,
+    },
     /// Construct a new instance of the indicated type and store a reference to it.
     NewInstance { reg: u8, lit: IdType },
     /// Construct a new array of the indicated type and size in size_reg and store a reference to it.
-    NewArray { reg: u8, size_reg: u8, lit: IdType },
+    NewArray {
+        /// 4 bits register
+        reg: u8,
+        /// 4 bits register
+        size_reg: u8,
+        lit: IdType,
+    },
     /// Construct a new array of the indicated type and size fill it with the values of the
     /// given registers.
     ///