Rise Up!

// 1-bit half adder module ha(sum, cout, a, b); output sum, cout; input a, b; assign sum=a^b; assign cout=a&b; endmodule // 16-bit incrementer module inc(b, a); parameter BITS = 16; output [BITS-1:0] b; input [BITS-1:0] a; wire [BITS-1:0] c; ha g(b[0], c[0], a[0], 1); genvar i; for (i=1; i<BITS; i=i+1) begin:bitpos ha g(b[i], c[i], a[i], c[i-1]); end endmodule // rise-up to next multiple of 32 module riseup(b, a); output [15:0] b; input [15:0] a; wire [10:0] c; inc #(.BITS(11)) plus1(c, a[15:5]); assign b = {((|a[4:0]) ? c : a[15:5]), 5'b0}; endmodule // reference implementation module refriseup(b, a); output [15:0] b; input [15:0] a; reg [15:0] t; assign b = t; always @ (a) begin t = a; while (t % 32 != 0) t = t + 1; end endmodule // TEST BENCH module testbench; reg [15:0] a; wire [15:0] b, refb; integer correct = 0; integer failed = 0; riseup uut(b, a); refriseup oracle(refb, a); initial begin a = 0; repeat (65536) begin #1 if (b != refb) begin $display("Wrong: refriseup of %d was %d, but riseup was %d", a, refb, b); failed = failed + 1; end else begin correct = correct + 1; end a = a + 1; end $display("All cases tested; %d correct, %d failed", correct, failed); $finish; end endmodule