introduce base class for get_slot and get_byte called getter

lib/register/instruction.rb

@@ -118,6 +118,7 @@ module Register
 end
 
 require_relative "instructions/setter"
+require_relative "instructions/getter"
 require_relative "instructions/set_slot"
 require_relative "instructions/get_slot"
 require_relative "instructions/set_byte"

lib/register/instructions/get_byte.rb

@@ -5,23 +5,16 @@ module Register
   # indexes are 1 based (as for slots) , which means we sacrifice a byte of every word
   #        for our sanity
 
-  class GetByte < Instruction
+  class GetByte < Getter
 
     # If you had a c array (of int8) and index offset
     # the instruction would do register = array[index]
     # The arguments are in the order that makes sense for the Instruction name
     # So GetSlot means the slot (array and index) moves to the register (last argument)
-    def initialize source , array , index , register
-      super(source)
-      @array = array
-      @index = index
-      @register = register
-      raise "index 0 " if index == 0
-      raise "Not integer or reg #{index}" unless index.is_a?(Numeric) or RegisterValue.look_like_reg(index)
-      raise "Not register #{register}" unless RegisterValue.look_like_reg(register)
-      raise "Not register #{array}" unless RegisterValue.look_like_reg(array)
-    end
-    attr_accessor :array , :index , :register
+    # def initialize source , array , index , register
+    #   super
+    # end
+    # attr_accessor :array , :index , :register
 
     def to_s
       "GetByte: #{array}[#{index}] -> #{register}"

lib/register/instructions/get_slot.rb

@@ -4,31 +4,21 @@ module Register
   # SetSlot moves data into memory from a register.
   # Both use a base memory (a register)
 
-  # While the virtual machine has only one instruction (Set) to move data between slots,
-  # the register has two, namely GetSlot and SetSlot
-  #
   # This is because that is what cpu's can do. In programming terms this would be accessing
   #  an element in an array, in the case of GetSlot setting the value in the array.
 
   # btw: to move data between registers, use RegisterTransfer
 
-  class GetSlot < Instruction
+  class GetSlot < Getter
 
     # If you had a c array and index offset
     # the instruction would do register = array[index]
     # The arguments are in the order that makes sense for the Instruction name
     # So GetSlot means the slot (array and index) moves to the register (last argument)
-    def initialize source , array , index , register
-      super(source)
-      @array = array
-      @index = index
-      @register = register
-      raise "index 0 " if index == 0
-      raise "Not integer or reg #{index}" unless index.is_a?(Numeric) or RegisterValue.look_like_reg(index)
-      raise "Not register #{register}" unless RegisterValue.look_like_reg(register)
-      raise "Not register #{array}" unless RegisterValue.look_like_reg(array)
-    end
-    attr_accessor :array , :index , :register
+    # def initialize source , array , index , register
+    #   super
+    # end
+    # attr_accessor :array , :index , :register
 
     def to_s
       "GetSlot: #{array}[#{index}] -> #{register}"

lib/register/instructions/getter.rb

@@ -0,0 +1,34 @@
+module Register
+
+  # Getter is a base class for get instructions (GetSlot and GetByte , possibly more coming)
+  #
+  # The instruction that is modelled is loading data from an array into a register
+  #
+  # Getter has a
+  # - an array where the data comes from
+  # - and (array) index
+  # - Register that the data is moved to
+
+  # Getter and Setter api follow the pattern from -> to
+
+  class Getter < Instruction
+
+    # If you had a c array and index offset
+    # the instruction would do register = array[index]
+    # The arguments are in the order that makes sense for the Instruction name
+    # So GetSlot means the slot (array and index) moves to the register (last argument)
+    def initialize source , array , index , register
+      super(source)
+      @array = array
+      @index = index
+      @register = register
+      raise "index 0 " if index == 0
+      raise "Not integer or reg #{index}" unless index.is_a?(Numeric) or RegisterValue.look_like_reg(index)
+      raise "Not register #{register}" unless RegisterValue.look_like_reg(register)
+      raise "Not register #{array}" unless RegisterValue.look_like_reg(array)
+    end
+    attr_accessor :array , :index , :register
+
+  end
+
+end

lib/register/instructions/setter.rb

@@ -1,12 +1,15 @@
 module Register
   # Setter is a base class for set instructions (SetSlot and SetByte , possibly more coming)
   #
-  # The instruction that is modelled is loading data from an array into a register
+  # The instruction that is modelled is loading data from a register into an array
   #
   # Setter has a
-  # - Register that the data is moved to
-  # - an array where the data comes from
+  # - Register that the data is comes from
+  # - an array where the data goes
   # - and (array) index
+
+  # Getter and Setter api follow the pattern from -> to
+
   class Setter < Instruction
 
     # If you had a c array and index offset