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yosys/techlibs/common/mul2dsp.v

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/*
* yosys -- Yosys Open SYnthesis Suite
*
* Copyright (C) 2012 Clifford Wolf <clifford@clifford.at>
* 2019 Eddie Hung <eddie@fpgeh.com>
* 2019 David Shah <dave@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.
*
* ---
*
* Tech-mapping rules for decomposing arbitrarily-sized $mul cells
* into an equivalent collection of smaller `DSP_NAME cells (with the
* same interface as $mul) no larger than `DSP_[AB]_MAXWIDTH, attached
* to $shl and $add cells.
*
*/
`ifndef DSP_A_MAXWIDTH
$fatal(1, "Macro DSP_A_MAXWIDTH must be defined");
`endif
`ifndef DSP_B_MAXWIDTH
$fatal(1, "Macro DSP_B_MAXWIDTH must be defined");
`endif
`ifndef DSP_B_MAXWIDTH
$fatal(1, "Macro DSP_B_MAXWIDTH must be defined");
`endif
`ifndef DSP_A_MAXWIDTH_PARTIAL
`define DSP_A_MAXWIDTH_PARTIAL `DSP_A_MAXWIDTH
`endif
`ifndef DSP_B_MAXWIDTH_PARTIAL
`define DSP_B_MAXWIDTH_PARTIAL `DSP_B_MAXWIDTH
`endif
`ifndef DSP_NAME
$fatal(1, "Macro DSP_NAME must be defined");
`endif
`define MAX(a,b) (a > b ? a : b)
`define MIN(a,b) (a < b ? a : b)
(* techmap_celltype = "$mul $__mul" *)
module _80_mul (A, B, Y);
parameter A_SIGNED = 0;
parameter B_SIGNED = 0;
parameter A_WIDTH = 1;
parameter B_WIDTH = 1;
parameter Y_WIDTH = 1;
input [A_WIDTH-1:0] A;
input [B_WIDTH-1:0] B;
output [Y_WIDTH-1:0] Y;
parameter _TECHMAP_CELLTYPE_ = "";
generate
if (0) begin end
`ifdef DSP_A_MINWIDTH
else if (A_WIDTH < `DSP_A_MINWIDTH)
wire _TECHMAP_FAIL_ = 1;
`endif
`ifdef DSP_B_MINWIDTH
else if (B_WIDTH < `DSP_B_MINWIDTH)
wire _TECHMAP_FAIL_ = 1;
`endif
`ifdef DSP_Y_MINWIDTH
else if (Y_WIDTH < `DSP_Y_MINWIDTH)
wire _TECHMAP_FAIL_ = 1;
`endif
else if (_TECHMAP_CELLTYPE_ == "$mul" && A_SIGNED != B_SIGNED)
wire _TECHMAP_FAIL_ = 1;
`ifdef DSP_SIGNEDONLY
else if (_TECHMAP_CELLTYPE_ == "$mul" && !A_SIGNED)
\$mul #(
.A_SIGNED(1),
.B_SIGNED(1),
.A_WIDTH(A_WIDTH + 1),
.B_WIDTH(B_WIDTH + 1),
.Y_WIDTH(Y_WIDTH)
) _TECHMAP_REPLACE_ (
.A({1'b0, A}),
.B({1'b0, B}),
.Y(Y)
);
`endif
else if (_TECHMAP_CELLTYPE_ == "$mul" && A_WIDTH < B_WIDTH)
\$mul #(
.A_SIGNED(B_SIGNED),
.B_SIGNED(A_SIGNED),
.A_WIDTH(B_WIDTH),
.B_WIDTH(A_WIDTH),
.Y_WIDTH(Y_WIDTH)
) _TECHMAP_REPLACE_ (
.A(B),
.B(A),
.Y(Y)
);
else begin
wire [1023:0] _TECHMAP_DO_ = "proc; clean";
`ifdef DSP_SIGNEDONLY
localparam sign_headroom = 1;
`else
localparam sign_headroom = 0;
`endif
genvar i;
if (A_WIDTH > `DSP_A_MAXWIDTH) begin
localparam n = (A_WIDTH-`DSP_A_MAXWIDTH+`DSP_A_MAXWIDTH_PARTIAL-sign_headroom-1) / (`DSP_A_MAXWIDTH_PARTIAL-sign_headroom);
localparam partial_Y_WIDTH = `MIN(Y_WIDTH, B_WIDTH+`DSP_A_MAXWIDTH_PARTIAL);
localparam last_A_WIDTH = A_WIDTH-n*(`DSP_A_MAXWIDTH_PARTIAL-sign_headroom);
localparam last_Y_WIDTH = B_WIDTH+last_A_WIDTH;
if (A_SIGNED && B_SIGNED) begin
wire signed [partial_Y_WIDTH-1:0] partial [n-1:0];
wire signed [last_Y_WIDTH-1:0] last_partial;
wire signed [Y_WIDTH-1:0] partial_sum [n:0];
end
else begin
wire [partial_Y_WIDTH-1:0] partial [n-1:0];
wire [last_Y_WIDTH-1:0] last_partial;
wire [Y_WIDTH-1:0] partial_sum [n:0];
end
for (i = 0; i < n; i=i+1) begin:slice
\$__mul #(
.A_SIGNED(sign_headroom),
.B_SIGNED(B_SIGNED),
.A_WIDTH(`DSP_A_MAXWIDTH_PARTIAL),
.B_WIDTH(B_WIDTH),
.Y_WIDTH(partial_Y_WIDTH)
) mul_slice (
.A({{sign_headroom{1'b0}}, A[i*(`DSP_A_MAXWIDTH_PARTIAL-sign_headroom) +: `DSP_A_MAXWIDTH_PARTIAL-sign_headroom]}),
.B(B),
.Y(partial[i])
);
// TODO: Currently a 'cascade' approach to summing the partial
// products is taken here, but a more efficient 'binary
// reduction' approach also exists...
if (i == 0)
assign partial_sum[i] = partial[i];
else
assign partial_sum[i] = (partial[i] << i*(`DSP_A_MAXWIDTH_PARTIAL-sign_headroom)) + partial_sum[i-1];
end
\$__mul #(
.A_SIGNED(A_SIGNED),
.B_SIGNED(B_SIGNED),
.A_WIDTH(last_A_WIDTH),
.B_WIDTH(B_WIDTH),
.Y_WIDTH(last_Y_WIDTH)
) mul_slice_last (
.A(A[A_WIDTH-1 -: last_A_WIDTH]),
.B(B),
.Y(last_partial)
);
assign partial_sum[n] = (last_partial << n*(`DSP_A_MAXWIDTH_PARTIAL-sign_headroom)) + partial_sum[n-1];
assign Y = partial_sum[n];
end
else if (B_WIDTH > `DSP_B_MAXWIDTH) begin
localparam n = (B_WIDTH-`DSP_B_MAXWIDTH+`DSP_B_MAXWIDTH_PARTIAL-sign_headroom-1) / (`DSP_B_MAXWIDTH_PARTIAL-sign_headroom);
localparam partial_Y_WIDTH = `MIN(Y_WIDTH, A_WIDTH+`DSP_B_MAXWIDTH_PARTIAL);
localparam last_B_WIDTH = B_WIDTH-n*(`DSP_B_MAXWIDTH_PARTIAL-sign_headroom);
localparam last_Y_WIDTH = A_WIDTH+last_B_WIDTH;
if (A_SIGNED && B_SIGNED) begin
wire signed [partial_Y_WIDTH-1:0] partial [n-1:0];
wire signed [last_Y_WIDTH-1:0] last_partial;
wire signed [Y_WIDTH-1:0] partial_sum [n:0];
end
else begin
wire [partial_Y_WIDTH-1:0] partial [n-1:0];
wire [last_Y_WIDTH-1:0] last_partial;
wire [Y_WIDTH-1:0] partial_sum [n:0];
end
for (i = 0; i < n; i=i+1) begin:slice
\$__mul #(
.A_SIGNED(A_SIGNED),
.B_SIGNED(sign_headroom),
.A_WIDTH(A_WIDTH),
.B_WIDTH(`DSP_B_MAXWIDTH_PARTIAL),
.Y_WIDTH(partial_Y_WIDTH)
) mul (
.A(A),
.B({{sign_headroom{1'b0}}, B[i*(`DSP_B_MAXWIDTH_PARTIAL-sign_headroom) +: `DSP_B_MAXWIDTH_PARTIAL-sign_headroom]}),
.Y(partial[i])
);
// TODO: Currently a 'cascade' approach to summing the partial
// products is taken here, but a more efficient 'binary
// reduction' approach also exists...
if (i == 0)
assign partial_sum[i] = partial[i];
else
assign partial_sum[i] = (partial[i] << i*(`DSP_B_MAXWIDTH_PARTIAL-sign_headroom)) + partial_sum[i-1];
end
\$__mul #(
.A_SIGNED(A_SIGNED),
.B_SIGNED(B_SIGNED),
.A_WIDTH(A_WIDTH),
.B_WIDTH(last_B_WIDTH),
.Y_WIDTH(last_Y_WIDTH)
) mul_last (
.A(A),
.B(B[B_WIDTH-1 -: last_B_WIDTH]),
.Y(last_partial)
);
assign partial_sum[n] = (last_partial << n*(`DSP_B_MAXWIDTH_PARTIAL-sign_headroom)) + partial_sum[n-1];
assign Y = partial_sum[n];
end
else begin
if (A_SIGNED)
wire signed [`DSP_A_MAXWIDTH-1:0] Aext = $signed(A);
else
wire [`DSP_A_MAXWIDTH-1:0] Aext = A;
if (B_SIGNED)
wire signed [`DSP_B_MAXWIDTH-1:0] Bext = $signed(B);
else
wire [`DSP_B_MAXWIDTH-1:0] Bext = B;
`DSP_NAME #(
.A_SIGNED(A_SIGNED),
.B_SIGNED(B_SIGNED),
.A_WIDTH(`DSP_A_MAXWIDTH),
.B_WIDTH(`DSP_B_MAXWIDTH),
.Y_WIDTH(`MIN(Y_WIDTH,`DSP_A_MAXWIDTH+`DSP_B_MAXWIDTH)),
) _TECHMAP_REPLACE_ (
.A(Aext),
.B(Bext),
.Y(Y)
);
end
end
endgenerate
endmodule
(* techmap_celltype = "$mul $__mul" *)
module _90_soft_mul (A, B, Y);
parameter A_SIGNED = 0;
parameter B_SIGNED = 0;
parameter A_WIDTH = 1;
parameter B_WIDTH = 1;
parameter Y_WIDTH = 1;
input [A_WIDTH-1:0] A;
input [B_WIDTH-1:0] B;
output [Y_WIDTH-1:0] Y;
// Indirection necessary since mapping
// back to $mul will cause recursion
generate
if (A_SIGNED && !B_SIGNED)
\$__soft_mul #(
.A_SIGNED(A_SIGNED),
.B_SIGNED(1),
.A_WIDTH(A_WIDTH),
.B_WIDTH(B_WIDTH+1),
.Y_WIDTH(Y_WIDTH)
) _TECHMAP_REPLACE_ (
.A(A),
.B({1'b0,B}),
.Y(Y)
);
else if (!A_SIGNED && B_SIGNED)
\$__soft_mul #(
.A_SIGNED(1),
.B_SIGNED(B_SIGNED),
.A_WIDTH(A_WIDTH+1),
.B_WIDTH(B_WIDTH),
.Y_WIDTH(Y_WIDTH)
) _TECHMAP_REPLACE_ (
.A({1'b0,A}),
.B(B),
.Y(Y)
);
else
\$__soft_mul #(
.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)
);
endgenerate
endmodule
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