hdlbits-Vector2

Vector2

A 32-bit vector can be viewed as containing 4 bytes (bits [31:24], [23:16], etc.). Build a circuit that will reverse the byte ordering of the 4-byte word.

AaaaaaaaBbbbbbbbCcccccccDddddddd => DdddddddCcccccccBbbbbbbbAaaaaaaa

This operation is often used when the endianness of a piece of data needs to be swapped, for example between little-endian x86 systems and the big-endian formats used in many Internet protocols.

Hint

Part-select can be used on both the left side and right side of an assignment.

solution

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

    // assign out[31:24] = ...;
    assign out[31:24] = in[ 7: 0];
    assign out[23:16] = in[15: 8];
    assign out[15: 8] = in[23:16];
    assign out[ 7: 0] = in[31:24];
endmodule