🎓 Topic assembly programming --- Counting to 10 example (#228)

Author: jameshughes89

site/topics/programming/counting_10.esap

@@ -0,0 +1,11 @@
+LDAD 0
+SAVA 0xF
+LDAR 0xF
+LDBD 1
+ADAB
+SAVA 0xF
+OUTU 0xF
+LDBD 10
+SUAB
+JMPS 0x2
+HALT

site/topics/programming/counting_10.hex

@@ -0,0 +1,12 @@
+v2.0 raw
+0x20
+0x5f
+0x1f
+0x41
+0x70
+0x5f
+0xdf
+0x4a
+0x80
+0xb2
+0xf0

site/topics/programming/programming-assembly.rst

@@ -155,6 +155,69 @@ Count to 10
 
 
 
+Count to 10
+===========
+
+* With the use of the assembler, the programs are easier to write and understand
+* This is important as solving complex problems is challenging enough as is
+
+    * The tedium of machine code only makes solving complex problems that much more difficult
+
+
+* Consider the more complex problem of counting to 10
+
+    * Output the numbers ``1`` to ``10``
+    * This may sound simple, but it is challenging when programming at such a low level
+
+
+* This problem combines two of the previous problems
+
+    * Counting forever
+
+        * requires looping
+
+
+    * Checking if a value is less than 10
+
+        * requires branching
+
+
+* Below is the assembly and corresponding machine code for a solution to this problem
+
+    .. list-table:: Count to 10
+        :header-rows: 1
+        :align: center
+
+        * - Assembly
+          - Machine Code
+
+        * - .. literalinclude:: counting_10.esap
+                :language: text
+                :lineno-match:
+
+          - .. literalinclude:: counting_10.hex
+                :language: text
+                :lineno-match:
+
+
+* Notice how the count value must be preserved before the subtraction can happen
+* Here, the ``JMPS`` instruction is used like a kind of while loop
+
+    * While the count is less than 10, jump
+
+
+* Note that, when running the program, it will appear to count ``0`` -- ``10``
+
+    * This is due to the simulator and how the output register starts with a ``0``
+
+
+* Additionally, the starting instructions of ``LDAD 0`` and ``SAVA 0xF`` could have been excluded
+
+    * The simulator initializes RAM with ``0``\s
+    * However, having clear and intentional code is preferred
+
+
+
 For Next Time
 =============