* 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
endgenerate
endmodule
-`ifndef NO_MUXFN
-module \$shiftx (A, B, Y);
+module \$__XILINX_MUX_ (A, B, Y);
parameter A_SIGNED = 0;
parameter B_SIGNED = 0;
parameter A_WIDTH = 1;
input [B_WIDTH-1:0] B;
output [Y_WIDTH-1:0] Y;
+ parameter [A_WIDTH-1:0] _TECHMAP_CONSTMSK_A_ = 0;
+ parameter [A_WIDTH-1:0] _TECHMAP_CONSTVAL_A_ = 0;
parameter [B_WIDTH-1:0] _TECHMAP_CONSTMSK_B_ = 0;
parameter [B_WIDTH-1:0] _TECHMAP_CONSTVAL_B_ = 0;
+ function integer compute_num_leading_X_in_A;
+ integer i, c;
+ begin
+ compute_num_leading_X_in_A = 0;
+ c = 1;
+ for (i = A_WIDTH-1; i >= 0; i=i-1) begin
+ if (!_TECHMAP_CONSTMSK_A_[i] || _TECHMAP_CONSTVAL_A_[i] !== 1'bx)
+ c = 0;
+ compute_num_leading_X_in_A = compute_num_leading_X_in_A + c;
+ end
+ end
+ endfunction
+ localparam num_leading_X_in_A = compute_num_leading_X_in_A();
+
generate
genvar i, j;
- if (B_SIGNED) begin
- if (_TECHMAP_CONSTMSK_B_[B_WIDTH-1] && _TECHMAP_CONSTVAL_B_[B_WIDTH-1] == 1'b0)
- // 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;
+ // Bit-blast
+ if (Y_WIDTH > 1) begin
+ for (i = 0; i < Y_WIDTH; i++)
+ \$__XILINX_MUX_ #(.A_SIGNED(A_SIGNED), .B_SIGNED(B_SIGNED), .A_WIDTH(A_WIDTH-Y_WIDTH+1), .B_WIDTH(B_WIDTH), .Y_WIDTH(1'd1)) bitblast (.A(A[A_WIDTH-Y_WIDTH+i:i]), .B(B), .Y(Y[i]));
+ end
+ // If the LSB of B is constant zero (and Y_WIDTH is 1) then
+ // we can optimise by removing every other entry from A
+ // and popping the constant zero from B
+ else if (_TECHMAP_CONSTMSK_B_[0] && !_TECHMAP_CONSTVAL_B_[0]) begin
+ wire [(A_WIDTH+1)/2-1:0] A_i;
+ for (i = 0; i < (A_WIDTH+1)/2; i++)
+ assign A_i[i] = A[i*2];
+ \$__XILINX_MUX_ #(.A_SIGNED(A_SIGNED), .B_SIGNED(B_SIGNED), .A_WIDTH((A_WIDTH+1'd1)/2'd2), .B_WIDTH(B_WIDTH-1'd1), .Y_WIDTH(Y_WIDTH)) _TECHMAP_REPLACE_ (.A(A_i), .B(B[B_WIDTH-1:1]), .Y(Y));
end
- else if (Y_WIDTH > 1) begin
- wire _TECHMAP_FAIL_ = 1;
+ // Trim off any leading 1'bx -es in A, and resize B accordingly
+ else if (num_leading_X_in_A > 0) begin
+ localparam A_WIDTH_new = A_WIDTH - num_leading_X_in_A;
+ localparam B_WIDTH_new = $clog2(A_WIDTH_new);
+ \$__XILINX_MUX_ #(.A_SIGNED(A_SIGNED), .B_SIGNED(B_SIGNED), .A_WIDTH(A_WIDTH_new), .B_WIDTH(B_WIDTH_new), .Y_WIDTH(Y_WIDTH)) _TECHMAP_REPLACE_ (.A(A[A_WIDTH_new-1:0]), .B(B[B_WIDTH_new-1:0]), .Y(Y));
end
else if (B_WIDTH < 3 || A_WIDTH <= 4) begin
- wire _TECHMAP_FAIL_ = 1;
+ \$shiftx #(.A_SIGNED(A_SIGNED), .B_SIGNED(B_SIGNED), .A_WIDTH(A_WIDTH), .B_WIDTH(B_WIDTH), .Y_WIDTH(Y_WIDTH)) _TECHMAP_REPLACE_ (.A(A), .B(B), .Y(Y));
end
else if (B_WIDTH == 3) begin
localparam a_width0 = 2 ** 2;
localparam a_widthN = A_WIDTH - a_width0;
wire T0, T1;
- \$shiftx #(.A_SIGNED(A_SIGNED), .B_SIGNED(B_SIGNED), .A_WIDTH(a_width0), .B_WIDTH(2), .Y_WIDTH(Y_WIDTH)) fpga_shiftx (.A(A[a_width0-1:0]), .B(B[2-1:0]), .Y(T0));
- \$shiftx #(.A_SIGNED(A_SIGNED), .B_SIGNED(B_SIGNED), .A_WIDTH(a_widthN), .B_WIDTH($clog2(a_widthN)), .Y_WIDTH(Y_WIDTH)) fpga_shiftx_last (.A(A[A_WIDTH-1:a_width0]), .B(B[$clog2(a_widthN)-1:0]), .Y(T1));
- MUXF7 fpga_mux (.I0(T0), .I1(T1), .S(B[B_WIDTH-1]), .O(Y));
+ \$shiftx #(.A_SIGNED(A_SIGNED), .B_SIGNED(B_SIGNED), .A_WIDTH(a_width0), .B_WIDTH(2), .Y_WIDTH(Y_WIDTH)) fpga_soft_mux (.A(A[a_width0-1:0]), .B(B[2-1:0]), .Y(T0));
+ if (a_widthN > 1)
+ \$shiftx #(.A_SIGNED(A_SIGNED), .B_SIGNED(B_SIGNED), .A_WIDTH(a_widthN), .B_WIDTH($clog2(a_widthN)), .Y_WIDTH(Y_WIDTH)) fpga_soft_mux_last (.A(A[A_WIDTH-1:a_width0]), .B(B[$clog2(a_widthN)-1:0]), .Y(T1));
+ else
+ assign T1 = A[A_WIDTH-1];
+ MUXF7 fpga_hard_mux (.I0(T0), .I1(T1), .S(B[B_WIDTH-1]), .O(Y));
end
else if (B_WIDTH == 4) begin
localparam a_width0 = 2 ** 2;
wire T0, T1;
for (i = 0; i < 4; i++)
if (i < num_mux8)
- \$shiftx #(.A_SIGNED(A_SIGNED), .B_SIGNED(B_SIGNED), .A_WIDTH(a_width0), .B_WIDTH(2), .Y_WIDTH(Y_WIDTH)) fpga_shiftx (.A(A[i*a_width0+:a_width0]), .B(B[2-1:0]), .Y(T[i]));
- else if (i == num_mux8 && a_widthN > 0)
- \$shiftx #(.A_SIGNED(A_SIGNED), .B_SIGNED(B_SIGNED), .A_WIDTH(a_widthN), .B_WIDTH($clog2(a_widthN)), .Y_WIDTH(Y_WIDTH)) fpga_shiftx_last (.A(A[A_WIDTH-1:i*a_width0]), .B(B[$clog2(a_widthN)-1:0]), .Y(T[i]));
+ \$shiftx #(.A_SIGNED(A_SIGNED), .B_SIGNED(B_SIGNED), .A_WIDTH(a_width0), .B_WIDTH(2), .Y_WIDTH(Y_WIDTH)) fpga_soft_mux (.A(A[i*a_width0+:a_width0]), .B(B[2-1:0]), .Y(T[i]));
+ else if (i == num_mux8 && a_widthN > 0) begin
+ if (a_widthN > 1)
+ \$shiftx #(.A_SIGNED(A_SIGNED), .B_SIGNED(B_SIGNED), .A_WIDTH(a_widthN), .B_WIDTH($clog2(a_widthN)), .Y_WIDTH(Y_WIDTH)) fpga_soft_mux_last (.A(A[A_WIDTH-1:i*a_width0]), .B(B[$clog2(a_widthN)-1:0]), .Y(T[i]));
+ else
+ assign T[i] = A[A_WIDTH-1];
+ end
else
assign T[i] = 1'bx;
- MUXF7 fpga_mux_0 (.I0(T[0]), .I1(T[1]), .S(B[2]), .O(T0));
- MUXF7 fpga_mux_1 (.I0(T[2]), .I1(T[3]), .S(B[2]), .O(T1));
- MUXF8 fpga_mux_2 (.I0(T0), .I1(T1), .S(B[3]), .O(Y));
+ MUXF7 fpga_hard_mux_0 (.I0(T[0]), .I1(T[1]), .S(B[2]), .O(T0));
+ MUXF7 fpga_hard_mux_1 (.I0(T[2]), .I1(T[3]), .S(B[2]), .O(T1));
+ MUXF8 fpga_hard_mux_2 (.I0(T0), .I1(T1), .S(B[3]), .O(Y));
end
else begin
localparam a_width0 = 2 ** 4;
wire [(2**(B_WIDTH-4))-1:0] T;
for (i = 0; i < 2 ** (B_WIDTH-4); i++)
if (i < num_mux16)
- \$shiftx #(.A_SIGNED(A_SIGNED), .B_SIGNED(B_SIGNED), .A_WIDTH(a_width0), .B_WIDTH(4), .Y_WIDTH(Y_WIDTH)) fpga_shiftx (.A(A[i*a_width0+:a_width0]), .B(B[4-1:0]), .Y(T[i]));
+ \$__XILINX_MUX_ #(.A_SIGNED(A_SIGNED), .B_SIGNED(B_SIGNED), .A_WIDTH(a_width0), .B_WIDTH(4), .Y_WIDTH(Y_WIDTH)) fpga_soft_mux (.A(A[i*a_width0+:a_width0]), .B(B[4-1:0]), .Y(T[i]));
else if (i == num_mux16 && a_widthN > 0) begin
- \$shiftx #(.A_SIGNED(A_SIGNED), .B_SIGNED(B_SIGNED), .A_WIDTH(a_widthN), .B_WIDTH($clog2(a_widthN)), .Y_WIDTH(Y_WIDTH)) fpga_shiftx_last (.A(A[A_WIDTH-1:i*a_width0]), .B(B[$clog2(a_widthN)-1:0]), .Y(T[i]));
+ if (a_widthN > 1)
+ \$__XILINX_MUX_ #(.A_SIGNED(A_SIGNED), .B_SIGNED(B_SIGNED), .A_WIDTH(a_widthN), .B_WIDTH($clog2(a_widthN)), .Y_WIDTH(Y_WIDTH)) fpga_soft_mux_last (.A(A[A_WIDTH-1:i*a_width0]), .B(B[$clog2(a_widthN)-1:0]), .Y(T[i]));
+ else
+ assign T[i] = A[A_WIDTH-1];
end
else
assign T[i] = 1'bx;
- \$shiftx #(.A_SIGNED(A_SIGNED), .B_SIGNED(B_SIGNED), .A_WIDTH(2**(B_WIDTH-4)), .B_WIDTH(B_WIDTH-4), .Y_WIDTH(Y_WIDTH)) fpga_shiftx (.A(T), .B(B[B_WIDTH-1:4]), .Y(Y));
+ \$__XILINX_MUX_ #(.A_SIGNED(A_SIGNED), .B_SIGNED(B_SIGNED), .A_WIDTH(2**(B_WIDTH-4)), .B_WIDTH(B_WIDTH-4), .Y_WIDTH(Y_WIDTH)) _TECHMAP_REPLACE_ (.A(T), .B(B[B_WIDTH-1:4]), .Y(Y));
end
endgenerate
endmodule
-`endif // NO_MUXFN
+
+module \$_MUX8_ (A, B, C, D, E, F, G, H, S, T, U, Y);
+input A, B, C, D, E, F, G, H, S, T, U;
+output Y;
+ \$__XILINX_MUX_ #(.A_SIGNED(0), .B_SIGNED(0), .A_WIDTH(8), .B_WIDTH(3), .Y_WIDTH(1)) _TECHMAP_REPLACE_ (.A({H,G,F,E,D,C,B,A}), .B({U,T,S}), .Y(Y));
+endmodule
+
+module \$_MUX16_ (A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, S, T, U, V, Y);
+input A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, S, T, U, V;
+output Y;
+ \$__XILINX_MUX_ #(.A_SIGNED(0), .B_SIGNED(0), .A_WIDTH(16), .B_WIDTH(4), .Y_WIDTH(1)) _TECHMAP_REPLACE_ (.A({P,O,N,M,L,K,J,I,H,G,F,E,D,C,B,A}), .B({V,U,T,S}), .Y(Y));
+endmodule
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