rename register to risc

seems to fit the layer much better as we really have a very reduced
instruction set

lib/risc/instructions/syscall.rb

@@ -0,0 +1,23 @@
+module Risc
+
+  # name says it all really
+  # only arg is the method syscall name
+  # how the layer below executes these is really up to it
+
+  # Any function issuing a Syscall should also save the current message
+  # and restore it after the syscall, saving the return value in Return_index
+
+  class Syscall < Instruction
+
+    def initialize source ,name
+      super(source)
+      @name = name
+    end
+    attr_reader :name
+
+    def to_s
+      "Syscall: #{name}"
+    end
+
+  end
+end