(* techmap_celltype = "$lcu" *) module _80_lcu_han_carlson (P, G, CI, CO); parameter WIDTH = 2; (* force_downto *) input [WIDTH-1:0] P, G; input CI; (* force_downto *) output [WIDTH-1:0] CO; integer i, j; (* force_downto *) reg [WIDTH-1:0] p, g; wire [1023:0] _TECHMAP_DO_ = "proc; opt -fast"; always @* begin i = 0; p = P; g = G; // in almost all cases CI will be constant zero g[0] = g[0] | (p[0] & CI); if (i < $clog2(WIDTH)) begin // First layer: BK for (j = WIDTH - 1; j >= 0; j = j - 1) begin if (j % 2 == 1) begin g[j] = g[j] | p[j] & g[j - 1]; p[j] = p[j] & p[j - 1]; end end // Inner (log(WIDTH) - 1) layers: KS for (i = 1; i < $clog2(WIDTH); i = i + 1) begin for (j = WIDTH - 1; j >= 2**i; j = j - 1) begin if (j % 2 == 1) begin g[j] = g[j] | p[j] & g[j - 2**i]; p[j] = p[j] & p[j - 2**i]; end end end // Last layer: BK if (i < ($clog2(WIDTH) + 1)) begin for (j = WIDTH - 1; j >= 0; j = j - 1) begin if ((j % 2 == 0) && (j > 0)) begin g[j] = g[j] | p[j] & g[j - 1]; p[j] = p[j] & p[j - 1]; end end end end end assign CO = g; endmodule