init

src/logic.adb

@@ -0,0 +1,44 @@
+package body Logic is
+
+   --  @name Step
+   --  @return
+   --  @parameter N:Natural
+   --  @parameter O:Natural
+   --  @description Do one calculation step and safe the result to O.
+   procedure Step (N : Natural; O : out Natural) is
+
+   begin
+
+      if N mod 2 = 0 then
+         O := N / 2;
+      else
+         O := 3 * N + 1;
+      end if;
+
+   end Step;
+
+   --  @name Row
+   --  @return
+   --  @parameter N:Natural,Final
+   --  @description Calculate full row for design.
+   procedure Row (N : Natural; Final : out Natural) is
+      Old    : Natural := N;
+      Update : Natural;
+   begin
+
+      while (Old < (Natural'Last / 3)) and (not (Old = 1)) loop
+
+         Step (Old, Update);
+         Old := Update;
+
+      end loop;
+
+      if not (Old = 1) then
+         Old := 1;
+      end if;
+
+      Final := Old;
+
+   end Row;
+
+end Logic;

src/logic.ads

@@ -0,0 +1,19 @@
+package Logic is
+
+   --  @name Step
+   --  @return
+   --  @parameter N:Natural
+   --  @parameter O:Natural
+   --  @description Do one calculation step and safe the result to O.
+   procedure Step (N : Natural; O : out Natural) with
+     Depends => (O => N), Pre => (N < (Natural'Last / 3));
+
+   --  @name Row
+   --  @return
+   --  @parameter N:Natural,Final
+   --  @description Calculate full row for design.
+   procedure Row (N : Natural; Final : out Natural) with
+     Depends => (Final => N), Pre => (N < (Natural'Last / 3)),
+     Post    => (Final = 1);
+
+end Logic;

src/spark_mode.adb

@@ -0,0 +1,15 @@
+with Logic; use Logic;
+with Ada.Text_IO; use Ada.Text_IO;
+
+procedure Spark_Mode is
+
+   A, B : Natural;
+
+begin
+
+   A := 8_400;
+   Row (A, B);
+
+   Put_Line (B'Image);
+
+end Spark_Mode;