// © IBM Corp. 2020
// Licensed under the Apache License, Version 2.0 (the "License"), as modified by
// the terms below; you may not use the files in this repository except in
// compliance with the License as modified.
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//    necessary for implementation of the Work that are available from OpenPOWER
//    via the Power ISA End User License Agreement (EULA) are explicitly excluded
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// input phase is importent
// (change X (B) by switching xor/xnor )


module lq_agen_csmuxe(
   sum_0,
   sum_1,
   ci_b,
   sum
);

input [0:3]     sum_0;		// after xor
input [0:3]     sum_1;
input           ci_b;

output [0:3]    sum;

wire [0:3]      sum0_b;

wire [0:3]      sum1_b;

wire            int_ci;

wire            int_ci_t;

wire            int_ci_b;

//assign int_ci = (~ci_b);
tri_inv int_ci_0 (.y(int_ci), .a(ci_b));

//assign int_ci_t = (~ci_b);
tri_inv int_ci_t_0 (.y(int_ci_t), .a(ci_b));

//assign int_ci_b = (~int_ci_t);
tri_inv int_ci_b_0 (.y(int_ci_b), .a(int_ci_t));

//assign sum0_b[0] = (~(sum_0[0] & int_ci_b));
tri_nand2 #(.WIDTH(4)) sum0_b_0 (.y(sum0_b[0:3]), .a(sum_0[0:3]), .b({4{int_ci_b}}));

//assign sum1_b[0] = (~(sum_1[0] & int_ci));
tri_nand2 #(.WIDTH(4)) sum1_b_0 (.y(sum1_b[0:3]), .a(sum_1[0:3]), .b({4{int_ci}}));

//assign sum[0] = (~(sum0_b[0] & sum1_b[0]));
tri_nand2 #(.WIDTH(4)) sum0 (.y(sum[0:3]), .a(sum0_b[0:3]), .b(sum1_b[0:3]));

endmodule
