Add more verific/opers test cases

Signed-off-by: Clifford Wolf <clifford@clifford.at>

verific/opers/Makefile

-TESTS := wide_mux sel_mux
+TESTS := wide_mux sel_mux select wselect rednor
 
 all: $(addsuffix .status,$(TESTS))
 

verific/opers/rednor.sv

+module top (input [6:0] a, output y);
+  assign y = ~|a;
+endmodule

verific/opers/sel_mux.sv

-module top (input [2:0] s, input [7:0] a, output y);
+module top (input [2:0] s, input [5:0] a, output y);
   assign y = a[s];
 endmodule

verific/opers/select.sv

+module top (input [5:0] s, input [6:0] a, output reg y);
+  always @* begin
+    (* parallel_case *)
+    casez (s)
+      6'b?????1: y = a[0];
+      6'b????1?: y = a[1];
+      6'b???1??: y = a[2];
+      6'b??1???: y = a[3];
+      6'b?1????: y = a[4];
+      6'b1?????: y = a[5];
+      6'b000000: y = a[6];
+    endcase
+  end
+endmodule

verific/opers/wide_mux.sv

-module top (input [1:0] s, input [7:0] a, b, c, d, output reg [7:0] y);
+module top (input [1:0] s, input [5:0] a, b, c, d, output reg [5:0] y);
   always @* begin
     case (s)
       0: y = a;

verific/opers/wselect.sv

+module top (input [4:0] s, input [2:0] a, b, c, d, e, output reg [2:0] y);
+  always @* begin
+    (* parallel_case, full_case *)
+    casez (s)
+      5'b????1: y = a;
+      5'b???1?: y = b;
+      5'b??1??: y = c;
+      5'b?1???: y = d;
+      5'b1????: y = e;
+    endcase
+  end
+endmodule