techlibs/xilinx/mux_map.v

   1 /*
   2  *  yosys -- Yosys Open SYnthesis Suite
   3  *
   4  *  Copyright (C) 2012  Clifford Wolf <clifford@clifford.at>
   5  *                2019  Eddie Hung    <eddie@fpgeh.com>
   6  *
   7  *  Permission to use, copy, modify, and/or distribute this software for any
   8  *  purpose with or without fee is hereby granted, provided that the above
   9  *  copyright notice and this permission notice appear in all copies.
  10  *
  11  *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  12  *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  13  *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  14  *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  15  *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  16  *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  17  *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  18  *
  19  */
  20
  21 module \$shiftx (A, B, Y);
  22   parameter A_SIGNED = 0;
  23   parameter B_SIGNED = 0;
  24   parameter A_WIDTH = 1;
  25   parameter B_WIDTH = 1;
  26   parameter Y_WIDTH = 1;
  27
  28   input [A_WIDTH-1:0] A;
  29   input [B_WIDTH-1:0] B;
  30   output [Y_WIDTH-1:0] Y;
  31
  32   parameter [B_WIDTH-1:0] _TECHMAP_CONSTMSK_B_ = 0;
  33   parameter [B_WIDTH-1:0] _TECHMAP_CONSTVAL_B_ = 0;
  34
  35   generate
  36     genvar i, j;
  37     // TODO: Check if this opt still necessary
  38     if (B_SIGNED) begin
  39       if (_TECHMAP_CONSTMSK_B_[B_WIDTH-1] && _TECHMAP_CONSTVAL_B_[B_WIDTH-1] == 1'b0)
  40         // Optimisation to remove B_SIGNED if sign bit of B is constant-0
  41         \$__XILINX_MUX_  #(.A_SIGNED(A_SIGNED), .B_SIGNED(0), .A_WIDTH(A_WIDTH), .B_WIDTH(B_WIDTH-1'd1), .Y_WIDTH(Y_WIDTH)) _TECHMAP_REPLACE_ (.A(A), .B(B[B_WIDTH-2:0]), .Y(Y));
  42       else
  43         wire _TECHMAP_FAIL_ = 1;
  44     end
  45     else if (B_WIDTH < 3 || A_WIDTH <= 4) begin
  46       wire _TECHMAP_FAIL_ = 1;
  47     end
  48     else begin
  49         \$__XILINX_MUX_  #(.A_SIGNED(A_SIGNED), .B_SIGNED(B_SIGNED), .A_WIDTH(A_WIDTH), .B_WIDTH(B_WIDTH), .Y_WIDTH(Y_WIDTH)) _TECHMAP_REPLACE_ (.A(A), .B(B), .Y(Y));
  50     end
  51   endgenerate
  52 endmodule