added mpardemo

[slipway.git] / misc / mpardemo.v

diff --git a/misc/mpardemo.v b/misc/mpardemo.v
new file mode 100644 (file)
index 0000000..27a9766
--- /dev/null
+++ b/misc/mpardemo.v
@@ -0,0 +1,35 @@
+module half_add(a, b, s, c);
+  input a, b;
+  output s, c;
+  assign s = a ^ b;
+  assign c = a & b;
+endmodule /* half_add */
+
+module add(a, b, ci, o, co);
+   input a, b, ci;
+   output o, co;
+   wire c1, c2, x;
+   half_add h1(a, b,  x, c1);
+   half_add h2(x, ci, o, c2);
+   assign co = c1 | c2;
+endmodule /* add */
+
+module main(a, b, ci, out);
+
+   input  [7:0] a;
+   input  [7:0] b;
+   input        ci;
+   output [8:0] out;
+   wire   [7:0] c;
+
+   add a1(a[0], b[0], ci,   out[0], c[0]);
+   add a2(a[1], b[1], c[0], out[1], c[1]);
+   add a3(a[2], b[2], c[1], out[2], c[2]);
+   add a4(a[3], b[3], c[2], out[3], c[3]);
+   add a5(a[4], b[4], c[3], out[4], c[4]);
+   add a6(a[5], b[5], c[4], out[5], c[5]);
+   add a7(a[6], b[6], c[5], out[6], c[6]);
+   add a8(a[7], b[7], c[6], out[7], out[8]);
+
+endmodule /* main */
+