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/*
* yosys -- Yosys Open SYnthesis Suite
*
* Copyright (C) 2012 Clifford Wolf <clifford@clifford.at>
* 2019 Eddie Hung <eddie@fpgeh.com>
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*
*/
// The purpose of these mapping rules is to allow preserve all (sufficiently
// wide) $shiftx cells during 'techmap' so that they can be mapped to hard
// resources, rather than being bit-blasted to gates during 'techmap'
// execution
module \$shiftx (A, B, Y);
parameter A_SIGNED = 0;
parameter B_SIGNED = 0;
parameter A_WIDTH = 1;
parameter B_WIDTH = 1;
parameter Y_WIDTH = 1;
(* force_downto *)
input [A_WIDTH-1:0] A;
(* force_downto *)
input [B_WIDTH-1:0] B;
(* force_downto *)
output [Y_WIDTH-1:0] Y;
parameter [B_WIDTH-1:0] _TECHMAP_CONSTMSK_B_ = 0;
parameter [B_WIDTH-1:0] _TECHMAP_CONSTVAL_B_ = 0;
generate
if (B_SIGNED) begin
if (_TECHMAP_CONSTMSK_B_[B_WIDTH-1] && (_TECHMAP_CONSTVAL_B_[B_WIDTH-1] == 1'b0 || _TECHMAP_CONSTVAL_B_[B_WIDTH-1] === 1'bx))
// Optimisation to remove B_SIGNED if sign bit of B is constant-0
\$shiftx #(
.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)
);
else
wire _TECHMAP_FAIL_ = 1;
end
else begin
if (((A_WIDTH + Y_WIDTH - 1) / Y_WIDTH) < `MIN_MUX_INPUTS)
wire _TECHMAP_FAIL_ = 1;
else
\$__XILINX_SHIFTX #(
.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)
);
end
endgenerate
endmodule
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