Add arithmetic unit, disable gtkwave

1 files changed, 27 insertions, 0 deletions

diff --git a/nandgame/arith_unit.sv b/nandgame/arith_unit.sv
new file mode 100644
index 0000000..ebbaaf8
--- /dev/null
+++ b/nandgame/arith_unit.sv
@@ -0,0 +1,27 @@
+// nandgame logic unit
+
+`timescale 1us/1us
+
+`include "nandgame_types.v"
+
+module  arith_unit #(
+  parameter DATA_WIDTH = 16
+) (
+  input [(DATA_WIDTH-1):0] X,
+  input [(DATA_WIDTH-1):0] Y,
+  input ArithCode operation,
+
+  output logic [(DATA_WIDTH-1):0] RES
+);
+
+always_comb begin
+    case (operation)
+        ARITH_PLUS: RES = X + Y;
+        ARITH_MINUS:  RES = X - Y;
+        ARITH_INC: RES = X + 1;
+        ARITH_DEC: RES = X - 1;
+        default: RES = 0;
+    endcase
+end
+
+endmodule