Added files into modelsim folder

ModelSim/seven_seg_4digit.sv

@@ -0,0 +1,44 @@
+`ifndef SEVEN_SEG_4_H_SV
+`define SEVEN_SEG_4_H_SV
+
+`include "seven_seg.sv"
+module seven_seg_4digit (
+    input  logic [15:0] num,
+    output logic [7:0]  segments0,
+    output logic [7:0]  segments1,
+    output logic [7:0]  segments2,
+    output logic [7:0]  segments3
+);
+
+    // Rightmost digit
+    seven_seg digit0 (
+        .num(num[3:0]),
+        .rbi_inv(1'b0),
+        .segments(segments0)
+    );
+
+    // Second digit from right
+    seven_seg digit1 (
+        .num(num[7:4]),
+        .rbi_inv(1'b0),
+        .segments(segments1)
+    );
+
+    // Third digit from right
+    seven_seg digit2 (
+        .num(num[11:8]),
+        .rbi_inv(1'b0),
+        .segments(segments2)
+    );
+
+    // Leftmost digit
+    seven_seg digit3 (
+        .num(num[15:12]),
+        .rbi_inv(1'b0),
+        .segments(segments3)
+    );
+
+endmodule
+
+`endif
+