Repaired Sign extender module again to ensure only combinational logic used

(There was a compilation error before, also compiled and tested code on board)

modules/sign_extender.sv

@@ -8,13 +8,9 @@ module sign_extender #(in_width=4, out_width=5)(
 );
     logic [0:0] msb;
     assign msb = (val >> (in_width-1)) & 1'b1;
-    always_comb begin
-        if (op) begin
-            ext_val = { {(2**out_width-2**in_width){msb}}, val};
-        end
-        if (~op) begin
-            ext_val = ({{(2**out_width-2**in_width){1'b0}}, val});
-        end
-    end
+    assign ext_val = op
+        ? { {(2**out_width - 2**in_width){msb}}, val }
+        : { {(2**out_width - 2**in_width){1'b0}}, val };
+  
 endmodule
 `endif