1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
|
/*
* yosys -- Yosys Open SYnthesis Suite
*
* Copyright (C) 2012 Claire Xenia Wolf <claire@yosyshq.com>
* Copyright (C) 2018 gatecat <gatecat@ds0.me>
*
* 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_nexus_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;
wire _TECHMAP_FAIL_ = Y_WIDTH <= 4;
(* 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));
function integer round_up2;
input integer N;
begin
round_up2 = ((N + 1) / 2) * 2;
end
endfunction
localparam Y_WIDTH2 = round_up2(Y_WIDTH);
(* force_downto *)
wire [Y_WIDTH2-1:0] AA = A_buf;
(* force_downto *)
wire [Y_WIDTH2-1:0] BB = BI ? ~B_buf : B_buf;
(* force_downto *)
wire [Y_WIDTH2-1:0] BX = B_buf;
(* force_downto *)
wire [Y_WIDTH2+1:0] FCO, Y1;
genvar i;
// Carry feed-in
CCU2 #(
.INIT0("0xFFFF"),
.INIT1("0x00AA"),
.INJECT("NO")
) ccu2c_i (
.A0(1'b1), .B0(1'b1), .C0(1'b1), .D0(1'b1),
.A1(CI), .B1(1'b1), .C1(1'b1), .D1(1'b1),
.COUT(FCO[0])
);
generate for (i = 0; i < Y_WIDTH2; i = i + 2) begin:slice
CCU2 #(
.INIT0("0x96AA"),
.INIT1("0x96AA"),
.INJECT("NO")
) ccu2c_i (
.CIN(FCO[i]),
.A0(AA[i]), .B0(BX[i]), .C0(BI), .D0(1'b1),
.A1(AA[i+1]), .B1(BX[i+1]), .C1(BI), .D1(1'b1),
.S0(Y[i]), .S1(Y1[i]),
.COUT(FCO[i+2])
);
assign CO[i] = (AA[i] && BB[i]) || ((Y[i] ^ AA[i] ^ BB[i]) && (AA[i] || BB[i]));
if (i+1 < Y_WIDTH) begin
assign CO[i + 1] = (AA[i] && BB[i]) || ((Y[i] ^ AA[i] ^ BB[i]) && (AA[i] || BB[i]));
assign Y[i+1] = Y1[i];
end
end endgenerate
assign X = AA ^ BB;
endmodule
|
