improve exercise 5.12

resources/lang/en/exercises/5_12.php

@@ -15,5 +15,7 @@
         "(reg n) (reg val))).",
         '6' => "Extend the message-passing interface to the machine to provide access to this new information. To " .
         "test your analyzer, define the Fibonacci machine from figure 5.12 and examine the lists you constructed.",
+        '7' => "Figure 5.11:  A recursive factorial machine.",
+        '8' => "Figure 5.12:  Controller for a machine to compute Fibonacci numbers.",
     ],
 ];

resources/lang/ru/exercises/5_12.php

@@ -15,5 +15,7 @@
         "((op *) (reg n) (reg val))).",
         '6' => "Расширьте интерфейс сообщений машины и включите в него доступ к новой информации. Чтобы проверить " .
         "свой анализатор, примените его к машине Фибоначчи с рисунка 5.12 и рассмотрите получившиеся списки.",
+        '7' => "Рис. 5.11. Рекурсивная факториальная машина.",
+        '8' => "Рис. 5.12. Контроллер машины для вычисления чисел Фибоначчи.",
     ],
 ];

resources/views/exercise/listing/5_12.blade.php

@@ -6,3 +6,60 @@
     <li>{{ __('exercises/5_12.description.5') }}</li>
 </ul>
 <p>{{ __('exercises/5_12.description.6') }}</p>
+<pre><code>(controller
+   (assign continue (label fact-done))     ; set up final return address
+ fact-loop
+   (test (op =) (reg n) (const 1))
+   (branch (label base-case))
+   ;; Set up for the recursive call by saving n and continue.
+   ;; Set up continue so that the computation will continue
+   ;; at after-fact when the subroutine returns.
+   (save continue)
+   (save n)
+   (assign n (op -) (reg n) (const 1))
+   (assign continue (label after-fact))
+   (goto (label fact-loop))
+ after-fact
+   (restore n)
+   (restore continue)
+   (assign val (op *) (reg n) (reg val))   ; val now contains n(n - 1)!
+   (goto (reg continue))                   ; return to caller
+ base-case
+   (assign val (const 1))                  ; base case: 1! = 1
+   (goto (reg continue))                   ; return to caller
+ fact-done)
+</code></pre>
+<p>{{ __('exercises/5_12.description.7') }}</p>
+<pre><code>(controller
+   (assign continue (label fib-done))
+ fib-loop
+   (test (op <) (reg n) (const 2))
+   (branch (label immediate-answer))
+   ;; set up to compute Fib(n - 1)
+   (save continue)
+   (assign continue (label afterfib-n-1))
+   (save n)                           ; save old value of n
+   (assign n (op -) (reg n) (const 1)); clobber n to n - 1
+   (goto (label fib-loop))            ; perform recursive call
+ afterfib-n-1                         ; upon return, val contains Fib(n - 1)
+   (restore n)
+   (restore continue)
+   ;; set up to compute Fib(n - 2)
+   (assign n (op -) (reg n) (const 2))
+   (save continue)
+   (assign continue (label afterfib-n-2))
+   (save val)                         ; save Fib(n - 1)
+   (goto (label fib-loop))
+ afterfib-n-2                         ; upon return, val contains Fib(n - 2)
+   (assign n (reg val))               ; n now contains Fib(n - 2)
+   (restore val)                      ; val now contains Fib(n - 1)
+   (restore continue)
+   (assign val                        ;  Fib(n - 1) +  Fib(n - 2)
+           (op +) (reg val) (reg n)) 
+   (goto (reg continue))              ; return to caller, answer is in val
+ immediate-answer
+   (assign val (reg n))               ; base case:  Fib(n) = n
+   (goto (reg continue))
+ fib-done)
+</code></pre>
+<p>{{ __('exercises/5_12.description.8') }}</p>