fix get_internal_byte

improved operators and tests
some logic errors still

lib/risc/register_slot.rb

@@ -72,6 +72,7 @@ module Risc
     # from itself (the slot) and the register given
     def <=( reg )
       raise "not reg #{reg}" unless reg.is_a?(RegisterValue)
+      raise "Index must be register #{index}" unless(index.is_a?(RegisterValue))
       reg_to_byte = Risc.reg_to_byte("#{reg.class_name} -> #{register.class_name}[#{index}]" , reg , register, index)
       compiler.add_code(reg_to_byte) if compiler
       reg_to_byte

lib/risc/register_value.rb

@@ -162,6 +162,7 @@ module Risc
     # since << covers all other cases, this must have a RegisterSlot as the right
     def <=( right )
       raise "not implemented for #{right.class}:#{right}" unless right.is_a?( RegisterSlot )
+      raise "Right index must be register #{right.index}" unless(right.index.is_a?(RegisterValue))
       ins = Risc.byte_to_reg("#{right.register.type}[#{right.index}] -> #{self.type}" , right.register , right.index , self)
       compiler.add_code(ins) if compiler
       return ins