HBLbits_Verilog Basic_Vector4

 HBLbits_Verilog Basic_Vector4

a = {b,b,b,b,b,b};. The replication operator allows repeating a vector and concatenating them together:

{num{vector}}

This replicates vector by num times. num must be a constant. Both sets of braces are required.

Examples:

{5{1'b1}}           // 5'b11111 (or 5'd31 or 5'h1f)
{2{a,b,c}}          // The same as {a,b,c,a,b,c}
{3'd5, {2{3'd6}}}   // 9'b101_110_110. It's a concatenation of 101 with
                    // the second vector, which is two copies of 3'b110.

Build a circuit that sign-extends an 8-bit number to 32 bits. This requires a concatenation of 24 copies of the sign bit (i.e., replicate bit[7] 24 times) followed by the 8-bit number itself.

module top_module (
	input [7:0] in,
	output [31:0] out
);

	// Concatenate two things together:
	// 1: {in[7]} repeated 24 times (24 bits)
	// 2: in[7:0] (8 bits)
	assign out = { {24{in[7]}}, in };
	
endmodule