🥼 Lab instructions and registers --- More questions (#234)

Author: jameshughes89

site/labs/decoding-instructions/decoding-instructions-registers.rst

@@ -52,3 +52,43 @@ Registers
         * The same 10 inputs discussed above
         * An additional 3 inputs specifying which register the output should be saved to
 
+
+
+New Operation
+=============
+
+Currently there is no way to actually load data into the system.
+
+#. Add a new mode/instruction such that data can be loaded into a specific register
+
+    * Currently 1 bit is used to specify ALU or comparator operations
+
+        * These can be thought of as *modes*
+
+
+    * Add an additional bit to allow for selecting between up to 4 modes
+
+        * 2 mode bits
+        * 3 bits that served as selecting a specific operation
+        * Two sets of 3 bits for specifying 2 source registers
+        * 3 bits for a destination register
+
+
+    * Update the system such that one of these 4 modes allows for loading data directly to a register
+
+        * The 3 destination register bits specify where the data is to be stored
+        * 8 bits of the 9 available for the operator and 3 source registers specify the 8 bit data
+
+
+    * For example, consider the below bit patterns and their meanings
+
+        * ``00 110 101 010 111`` --- ``add`` on registers 5 and 2 and store in 7
+        * ``01 110 101 010 111`` --- ``>=`` on registers 5 and 2 and store in 7
+        * ``10 1 10101010 111`` --- Store ``0b10101010`` (``170``) in register 7
+
+
+
+#. Add a new forth mode such that data can be copy between registers
+
+    * Here, only one set of 3 bits specifying the source register is required
+    * ``11 110 101 010 111`` --- Copy contests of register 2 to register 7