Rename variables to be more clear, document

1 files changed, 19 insertions, 15 deletions

diff --git a/nandgame/logic_unit.sv b/nandgame/logic_unit.sv
index 89fe8fb..68f5c23 100644
--- a/nandgame/logic_unit.sv
+++ b/nandgame/logic_unit.sv
@@ -10,28 +10,32 @@
 module logic_unit #(
   parameter DATA_WIDTH = 16
 ) (
-  input [(DATA_WIDTH-1):0] X,
-  input [(DATA_WIDTH-1):0] Y,
-  input LogicCode operation,
-
-  output logic [(DATA_WIDTH-1):0] RES
+  // first operand
+  input [(DATA_WIDTH-1):0] X_in,
+  // second operand
+  input [(DATA_WIDTH-1):0] Y_in,
+  // opcode, see LogicCode
+  input LogicCode logic_operation_in,
+
+  // result of operation
+  output logic [(DATA_WIDTH-1):0] result_out
 );
 
 // learning: instead of this nested ternary...
-// assign RES = operation == LOGIC_AND ? (X & Y) : 
-//               operation == LOGIC_OR ? (X | Y) :
-//               operation == LOGIC_XOR ? (X ^ Y) :
-//               operation == LOGIC_NEGT ? (~X) : 0;
+// assign result_out = logic_operation_in == LOGIC_AND ? (X_in & Y_in) : 
+//               logic_operation_in == LOGIC_OR ? (X_in | Y_in) :
+//               logic_operation_in == LOGIC_XOR ? (X_in ^ Y_in) :
+//               logic_operation_in == LOGIC_NEGT ? (~X_in) : 0;
 
 // ... you can do this:
 
 always_comb begin
-    case (operation)
-        LOGIC_AND: RES = X & Y;
-        LOGIC_OR:  RES = X | Y;
-        LOGIC_XOR: RES = X ^ Y;
-        LOGIC_NEGT: RES = ~X;
-        default: RES = 0;
+    case (logic_operation_in)
+        LOGIC_AND: result_out = X_in & Y_in;
+        LOGIC_OR:  result_out = X_in | Y_in;
+        LOGIC_XOR: result_out = X_in ^ Y_in;
+        LOGIC_NEGT: result_out = ~X_in;
+        default: result_out = 0;
     endcase
 end