test: validate parametric 32x4 layer with parallelism 8

rtl/mac_unit.v

@@ -0,0 +1,23 @@
+module mac_unit #(
+    parameter DATA_WIDTH = 16,
+    parameter ACC_WIDTH  = 40
+)(
+    input  signed [DATA_WIDTH-1:0] x,
+    input  signed [DATA_WIDTH-1:0] w,
+    input  signed [ACC_WIDTH-1:0] acc_in,
+    output signed [ACC_WIDTH-1:0] acc_out
+);
+
+    localparam PROD_WIDTH = 2 * DATA_WIDTH;
+
+    wire signed [PROD_WIDTH-1:0] product;
+    wire signed [ACC_WIDTH-1:0] product_ext;
+
+    assign product = x * w;
+
+    assign product_ext =
+        {{(ACC_WIDTH-PROD_WIDTH){product[PROD_WIDTH-1]}}, product};
+
+    assign acc_out = acc_in + product_ext;
+
+endmodule