first go at translating DynamicCall to risc

lib/risc/instructions/branch.rb

@@ -53,6 +53,20 @@ module Risc
 
   end
 
+  # dynamic version of an Unconditional branch that jumps to the contents
+  # of a register instead of a hardcoded address
+  # As Branches jump to Labels, this is not derived from Branch
+  # PS: to conditionally jump to a dynamic adddress we do a normal branch
+  #     over the dynamic one and then a dynamic one. Save us having all types of branches
+  #     in two versions
+  class DynamicJump < Instruction
+    def initialize( source , register )
+      super(source)
+      @register = register
+    end
+    attr_reader :register
+  end
+
   # branch if two registers contain same value
   class IsSame < Branch
     attr_reader :left , :right