mirror of https://github.com/YosysHQ/yosys.git
333 lines
9.1 KiB
Verilog
333 lines
9.1 KiB
Verilog
/*
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* yosys -- Yosys Open SYnthesis Suite
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*
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* Copyright (C) 2012 Clifford Wolf <clifford@clifford.at>
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* 2019 Eddie Hung <eddie@fpgeh.com>
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* 2019 David Shah <dave@ds0.me>
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*
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* Permission to use, copy, modify, and/or distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*
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* ---
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*
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* Tech-mapping rules for decomposing arbitrarily-sized $mul cells
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* into an equivalent collection of smaller `DSP_NAME cells (with the
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* same interface as $mul) no larger than `DSP_[AB]_MAXWIDTH, attached
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* to $shl and $add cells.
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*
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*/
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`ifndef DSP_A_MAXWIDTH
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$error("Macro DSP_A_MAXWIDTH must be defined");
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`endif
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`ifndef DSP_B_MAXWIDTH
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$error("Macro DSP_B_MAXWIDTH must be defined");
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`endif
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`ifndef DSP_NAME
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$error("Macro DSP_NAME must be defined");
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`endif
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`define MAX(a,b) (a > b ? a : b)
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`define MIN(a,b) (a < b ? a : b)
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module \$mul (A, B, Y);
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parameter A_SIGNED = 0;
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parameter B_SIGNED = 0;
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parameter A_WIDTH = 1;
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parameter B_WIDTH = 1;
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parameter Y_WIDTH = 1;
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input [A_WIDTH-1:0] A;
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input [B_WIDTH-1:0] B;
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output [Y_WIDTH-1:0] Y;
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generate
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if (A_SIGNED != B_SIGNED)
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wire _TECHMAP_FAIL_ = 1;
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// NB: A_SIGNED == B_SIGNED from here
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`ifdef DSP_SIGNEDONLY
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else if (!A_SIGNED)
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\$mul #(
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.A_SIGNED(1),
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.B_SIGNED(1),
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.A_WIDTH(A_WIDTH + 1),
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.B_WIDTH(B_WIDTH + 1),
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.Y_WIDTH(Y_WIDTH)
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) _TECHMAP_REPLACE_ (
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.A({1'b0, A}),
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.B({1'b0, B}),
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.Y(Y)
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);
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`endif
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else if (A_WIDTH < B_WIDTH)
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\$mul #(
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.A_SIGNED(B_SIGNED),
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.B_SIGNED(A_SIGNED),
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.A_WIDTH(B_WIDTH),
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.B_WIDTH(A_WIDTH),
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.Y_WIDTH(Y_WIDTH)
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) _TECHMAP_REPLACE_ (
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.A(B),
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.B(A),
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.Y(Y)
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);
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else
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\$__mul #(
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.A_SIGNED(A_SIGNED),
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.B_SIGNED(B_SIGNED),
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.A_WIDTH(A_WIDTH),
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.B_WIDTH(B_WIDTH),
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.Y_WIDTH(Y_WIDTH)
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) _TECHMAP_REPLACE_ (
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.A(A),
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.B(B),
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.Y(Y)
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);
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endgenerate
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endmodule
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module \$__mul (A, B, Y);
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parameter A_SIGNED = 0;
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parameter B_SIGNED = 0;
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parameter A_WIDTH = 1;
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parameter B_WIDTH = 1;
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parameter Y_WIDTH = 1;
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input [A_WIDTH-1:0] A;
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input [B_WIDTH-1:0] B;
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output [Y_WIDTH-1:0] Y;
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wire [1023:0] _TECHMAP_DO_ = "proc; clean";
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`ifdef DSP_SIGNEDONLY
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localparam sign_headroom = 1;
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`else
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localparam sign_headroom = 0;
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`endif
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genvar i;
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generate
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if (0) begin end
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`ifdef DSP_A_MINWIDTH
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else if (A_WIDTH < `DSP_A_MINWIDTH)
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wire _TECHMAP_FAIL_ = 1;
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`endif
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`ifdef DSP_B_MINWIDTH
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else if (B_WIDTH < `DSP_B_MINWIDTH)
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wire _TECHMAP_FAIL_ = 1;
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`endif
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`ifdef DSP_Y_MINWIDTH
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else if (Y_WIDTH < `DSP_Y_MINWIDTH)
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wire _TECHMAP_FAIL_ = 1;
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`endif
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else if (A_WIDTH > `DSP_A_MAXWIDTH) begin
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localparam n = (A_WIDTH+`DSP_A_MAXWIDTH-sign_headroom-1) / (`DSP_A_MAXWIDTH-sign_headroom);
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localparam partial_Y_WIDTH = `MIN(Y_WIDTH, B_WIDTH+`DSP_A_MAXWIDTH);
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localparam last_Y_WIDTH = `MIN(partial_Y_WIDTH, B_WIDTH+A_WIDTH-(n-1)*(`DSP_A_MAXWIDTH-sign_headroom));
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if (A_SIGNED && B_SIGNED) begin
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wire signed [partial_Y_WIDTH-1:0] partial [n-2:0];
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wire signed [last_Y_WIDTH-1:0] last_partial;
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wire signed [Y_WIDTH-1:0] partial_sum [n-1:0];
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end
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else begin
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wire [partial_Y_WIDTH-1:0] partial [n-1:0];
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wire [last_Y_WIDTH-1:0] last_partial;
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wire [Y_WIDTH-1:0] partial_sum [n-1:0];
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end
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\$__mul #(
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.A_SIGNED(sign_headroom),
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.B_SIGNED(B_SIGNED),
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.A_WIDTH(`DSP_A_MAXWIDTH),
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.B_WIDTH(B_WIDTH),
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.Y_WIDTH(partial_Y_WIDTH)
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) mul_slice_first (
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.A({{sign_headroom{1'b0}}, A[`DSP_A_MAXWIDTH-sign_headroom-1 : 0]}),
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.B(B),
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.Y(partial[0])
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);
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assign partial_sum[0] = partial[0];
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for (i = 1; i < n-1; i=i+1) begin:slice
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\$__mul #(
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.A_SIGNED(sign_headroom),
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.B_SIGNED(B_SIGNED),
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.A_WIDTH(`DSP_A_MAXWIDTH),
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.B_WIDTH(B_WIDTH),
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.Y_WIDTH(partial_Y_WIDTH)
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) mul_slice (
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.A({{sign_headroom{1'b0}}, A[i*(`DSP_A_MAXWIDTH-sign_headroom) +: `DSP_A_MAXWIDTH-sign_headroom]}),
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.B(B),
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.Y(partial[i])
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);
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// TODO: Currently a 'cascade' approach to summing the partial
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// products is taken here, but a more efficient 'binary
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// reduction' approach also exists...
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assign partial_sum[i] = (partial[i] << i*(`DSP_A_MAXWIDTH-sign_headroom)) + partial_sum[i-1];
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end
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localparam last_A_WIDTH = A_WIDTH-(n-1)*(`DSP_A_MAXWIDTH-sign_headroom);
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\$__mul #(
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.A_SIGNED(A_SIGNED),
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.B_SIGNED(B_SIGNED),
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.A_WIDTH(last_A_WIDTH),
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.B_WIDTH(B_WIDTH),
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.Y_WIDTH(last_Y_WIDTH)
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) mul_slice_last (
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.A(A[A_WIDTH-1 -: last_A_WIDTH]),
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.B(B),
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.Y(last_partial)
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);
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assign partial_sum[n-1] = (last_partial << (n-1)*(`DSP_A_MAXWIDTH-sign_headroom)) + partial_sum[n-2];
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assign Y = partial_sum[n-1];
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end
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else if (B_WIDTH > `DSP_B_MAXWIDTH) begin
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localparam n = (B_WIDTH+`DSP_B_MAXWIDTH-sign_headroom-1) / (`DSP_B_MAXWIDTH-sign_headroom);
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localparam partial_Y_WIDTH = `MIN(Y_WIDTH, A_WIDTH+`DSP_B_MAXWIDTH);
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localparam last_Y_WIDTH = `MIN(partial_Y_WIDTH, A_WIDTH+B_WIDTH-(n-1)*(`DSP_B_MAXWIDTH-sign_headroom));
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if (A_SIGNED && B_SIGNED) begin
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wire signed [partial_Y_WIDTH-1:0] partial [n-2:0];
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wire signed [last_Y_WIDTH-1:0] last_partial;
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wire signed [Y_WIDTH-1:0] partial_sum [n-1:0];
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end
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else begin
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wire [partial_Y_WIDTH-1:0] partial [n-1:0];
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wire [last_Y_WIDTH-1:0] last_partial;
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wire [Y_WIDTH-1:0] partial_sum [n-1:0];
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end
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\$__mul #(
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.A_SIGNED(A_SIGNED),
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.B_SIGNED(sign_headroom),
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.A_WIDTH(A_WIDTH),
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.B_WIDTH(`DSP_B_MAXWIDTH),
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.Y_WIDTH(partial_Y_WIDTH)
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) mul_first (
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.A(A),
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.B({{sign_headroom{1'b0}}, B[`DSP_B_MAXWIDTH-sign_headroom-1 : 0]}),
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.Y(partial[0])
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);
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assign partial_sum[0] = partial[0];
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for (i = 1; i < n-1; i=i+1) begin:slice
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\$__mul #(
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.A_SIGNED(A_SIGNED),
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.B_SIGNED(sign_headroom),
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.A_WIDTH(A_WIDTH),
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.B_WIDTH(`DSP_B_MAXWIDTH),
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.Y_WIDTH(partial_Y_WIDTH)
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) mul (
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.A(A),
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.B({{sign_headroom{1'b0}}, B[i*(`DSP_B_MAXWIDTH-sign_headroom) +: `DSP_B_MAXWIDTH-sign_headroom]}),
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.Y(partial[i])
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);
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// TODO: Currently a 'cascade' approach to summing the partial
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// products is taken here, but a more efficient 'binary
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// reduction' approach also exists...
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assign partial_sum[i] = (partial[i] << i*(`DSP_B_MAXWIDTH-sign_headroom)) + partial_sum[i-1];
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end
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localparam last_B_WIDTH = B_WIDTH-(n-1)*(`DSP_B_MAXWIDTH-sign_headroom);
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\$__mul #(
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.A_SIGNED(A_SIGNED),
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.B_SIGNED(B_SIGNED),
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.A_WIDTH(A_WIDTH),
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.B_WIDTH(last_B_WIDTH),
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.Y_WIDTH(last_Y_WIDTH)
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) mul_last (
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.A(A),
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.B(B[B_WIDTH-1 -: last_B_WIDTH]),
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.Y(last_partial)
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);
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assign partial_sum[n-1] = (last_partial << (n-1)*(`DSP_B_MAXWIDTH-sign_headroom)) + partial_sum[n-2];
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assign Y = partial_sum[n-1];
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end
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else begin
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if (A_SIGNED)
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wire signed [`DSP_A_MAXWIDTH-1:0] Aext = $signed(A);
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else
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wire [`DSP_A_MAXWIDTH-1:0] Aext = A;
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if (B_SIGNED)
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wire signed [`DSP_B_MAXWIDTH-1:0] Bext = $signed(B);
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else
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wire [`DSP_B_MAXWIDTH-1:0] Bext = B;
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`DSP_NAME #(
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.A_SIGNED(A_SIGNED),
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.B_SIGNED(B_SIGNED),
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.A_WIDTH(`DSP_A_MAXWIDTH),
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.B_WIDTH(`DSP_B_MAXWIDTH),
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.Y_WIDTH(`MIN(Y_WIDTH,`DSP_A_MAXWIDTH+`DSP_B_MAXWIDTH)),
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) _TECHMAP_REPLACE_ (
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.A(Aext),
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.B(Bext),
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.Y(Y)
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);
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end
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endgenerate
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endmodule
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(* techmap_celltype = "$__mul" *)
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module $__soft_mul (A, B, Y);
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parameter A_SIGNED = 0;
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parameter B_SIGNED = 0;
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parameter A_WIDTH = 1;
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parameter B_WIDTH = 1;
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parameter Y_WIDTH = 1;
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input [A_WIDTH-1:0] A;
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input [B_WIDTH-1:0] B;
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output [Y_WIDTH-1:0] Y;
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// Indirection necessary since mapping
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// back to $mul will cause recursion
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generate
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if (A_SIGNED && !B_SIGNED)
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\$__soft__mul #(
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.A_SIGNED(A_SIGNED),
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.B_SIGNED(1),
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.A_WIDTH(A_WIDTH),
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.B_WIDTH(B_WIDTH+1),
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.Y_WIDTH(Y_WIDTH)
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) _TECHMAP_REPLACE_ (
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.A(A),
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.B({1'b0,B}),
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.Y(Y)
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);
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else if (!A_SIGNED && B_SIGNED)
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\$__soft_mul #(
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.A_SIGNED(1),
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.B_SIGNED(B_SIGNED),
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.A_WIDTH(A_WIDTH+1),
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.B_WIDTH(B_WIDTH),
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.Y_WIDTH(Y_WIDTH)
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) _TECHMAP_REPLACE_ (
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.A({1'b0,A}),
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.B(B),
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.Y(Y)
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);
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else
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\$__soft_mul #(
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.A_SIGNED(A_SIGNED),
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.B_SIGNED(B_SIGNED),
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.A_WIDTH(A_WIDTH),
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.B_WIDTH(B_WIDTH),
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.Y_WIDTH(Y_WIDTH)
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) _TECHMAP_REPLACE_ (
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.A(A),
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.B(B),
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.Y(Y)
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);
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endgenerate
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endmodule
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