yosys/techlibs/nanoxplore/arith_map.v

77 lines
2.0 KiB
Verilog

/*
* yosys -- Yosys Open SYnthesis Suite
*
* Copyright (C) 2024 Miodrag Milanovic <micko@yosyshq.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.
*
*/
(* techmap_celltype = "$alu" *)
module _80_nx_cy_alu (A, B, CI, BI, X, Y, CO);
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] X, Y;
input CI, BI;
(* force_downto *)
output [Y_WIDTH-1:0] CO;
(* force_downto *)
wire [Y_WIDTH-1:0] COx;
wire _TECHMAP_FAIL_ = Y_WIDTH <= 2;
(* force_downto *)
wire [Y_WIDTH-1:0] A_buf, B_buf;
\$pos #(.A_SIGNED(A_SIGNED), .A_WIDTH(A_WIDTH), .Y_WIDTH(Y_WIDTH)) A_conv (.A(A), .Y(A_buf));
\$pos #(.A_SIGNED(B_SIGNED), .A_WIDTH(B_WIDTH), .Y_WIDTH(Y_WIDTH)) B_conv (.A(B), .Y(B_buf));
(* force_downto *)
wire [Y_WIDTH-1:0] AA = A_buf;
(* force_downto *)
wire [Y_WIDTH-1:0] BB = BI ? ~B_buf : B_buf;
genvar i;
generate for (i = 0; i < Y_WIDTH; i = i + 1) begin: slice
NX_CY_1BIT #(.first(i==0))
alu_i (
.CI(i==0 ? CI : COx[i-1]),
.A(AA[i]),
.B(BB[i]),
.S(Y[i]),
.CO(COx[i])
);
end: slice
endgenerate
NX_CY_1BIT alu_cout(
.CI(COx[Y_WIDTH-1]),
.A(1'b0),
.B(1'b0),
.S(CO[Y_WIDTH-1])
);
/* End implementation */
assign X = AA ^ BB;
endmodule