MIA processor now halts on the correct clock cycle

Closes #35 (closed)

src/simudator/processor/mia/modules/micro_memory.py

@@ -134,10 +134,6 @@ class MicroMemory(Module):
         micro controller sets control signals to other modules in accordance
         with the micro instruction pointed to.
         """
-        # Always set HALT to False so that an eventual previously signalled
-        # HALT is reset and execution can continue normally.
-        self.halt = False
-
         instruction = self.upc_s.get_value()
         if instruction is None:
             return
@@ -240,8 +236,27 @@ class MicroMemory(Module):
             case 0b1110:
                 self._conditional_jump(self.o_flag_val, 0, uadr_field)
             case 0b1111:
+                # Halt is handled by update_register
                 self.upc_control_s.update_value(0b011)
-                self.halt = True
+
+    def update_register(self) -> None:
+        """
+        Signal halt when the micro memory performs a halt instruction.
+
+        Notes
+        -----
+        Although the micro memory is not a register, this override is needed to
+        make sure a halt instruction is signalled on the actual clock cycle 
+        where it is "executed". All control signals for the halt will have been
+        propagated at the end of the previous cycle. If the halt signalling 
+        were to be done in update_logic, the halt would erroneously be signaled 
+        one cycle to early.
+        """
+        seq_field = (self.memory[self.curr_instr] >> 7) & 0b1111
+        if seq_field == 0b1111:
+            self.halt = True
+        else:
+            self.halt = False
 
     def _conditional_jump(self, flag, cond_value, uadr):
         """Helper function for executing a conditional jump to the specified uadr