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Revert "Remove wide mux inference"

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This reverts commit 738fdfe8f5.
This commit is contained in:
Eddie Hung 2019-06-14 12:50:24 -07:00
parent 691e145cda
commit b63b2a0bd4
5 changed files with 195 additions and 3 deletions
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1
CHANGELOG
View file

@ -22,6 +22,7 @@ Yosys 0.8 .. Yosys 0.8-dev
- Added "synth_ice40 -abc9" (experimental)
- Added "synth -abc9" (experimental)
- "synth_xilinx" to now infer hard shift registers, using new "shregmap -tech xilinx"
- "synth_xilinx" to now infer wide multiplexers
Yosys 0.7 .. Yosys 0.8

1
techlibs/xilinx/Makefile.inc
View file

@ -30,6 +30,7 @@ $(eval $(call add_share_file,share/xilinx,techlibs/xilinx/drams_map.v))
$(eval $(call add_share_file,share/xilinx,techlibs/xilinx/arith_map.v))
$(eval $(call add_share_file,share/xilinx,techlibs/xilinx/ff_map.v))
$(eval $(call add_share_file,share/xilinx,techlibs/xilinx/lut_map.v))
$(eval $(call add_share_file,share/xilinx,techlibs/xilinx/mux_map.v))
$(eval $(call add_share_file,share/xilinx,techlibs/xilinx/abc_xc7.box))
$(eval $(call add_share_file,share/xilinx,techlibs/xilinx/abc_xc7.lut))

120
techlibs/xilinx/cells_map.v
View file

@ -154,3 +154,123 @@ module \$__XILINX_SHREG_ (input C, input D, input [31:0] L, input E, output Q, o
end
endgenerate
endmodule
module \$__XILINX_SHIFTX (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 [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;
// Bit-blast
if (Y_WIDTH > 1) begin
for (i = 0; i < Y_WIDTH; i++)
\$__XILINX_SHIFTX #(.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_SHIFTX #(.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
// 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 = $clog2(A_WIDTH_new);
\$__XILINX_SHIFTX #(.A_SIGNED(A_SIGNED), .B_SIGNED(B_SIGNED), .A_WIDTH(A_WIDTH_new), .B_WIDTH(B_WIDTH_new), .Y_WIDTH(Y_WIDTH)) _TECHMAP_REPLACE_ (.A(A[A_WIDTH_new-1:0]), .B(B[B_WIDTH_new-1:0]), .Y(Y));
end
else if (B_WIDTH < 3 || A_WIDTH <= 4) begin
\$shiftx #(.A_SIGNED(A_SIGNED), .B_SIGNED(B_SIGNED), .A_WIDTH(A_WIDTH), .B_WIDTH(B_WIDTH), .Y_WIDTH(Y_WIDTH)) _TECHMAP_REPLACE_ (.A(A), .B(B), .Y(Y));
end
else if (B_WIDTH == 3) begin
localparam a_width0 = 2 ** 2;
localparam a_widthN = A_WIDTH - a_width0;
wire T0, T1;
\$shiftx #(.A_SIGNED(A_SIGNED), .B_SIGNED(B_SIGNED), .A_WIDTH(a_width0), .B_WIDTH(2), .Y_WIDTH(Y_WIDTH)) fpga_soft_mux (.A(A[a_width0-1:0]), .B(B[2-1:0]), .Y(T0));
if (a_widthN > 1)
\$shiftx #(.A_SIGNED(A_SIGNED), .B_SIGNED(B_SIGNED), .A_WIDTH(a_widthN), .B_WIDTH($clog2(a_widthN)), .Y_WIDTH(Y_WIDTH)) fpga_soft_mux_last (.A(A[A_WIDTH-1:a_width0]), .B(B[$clog2(a_widthN)-1:0]), .Y(T1));
else
assign T1 = A[A_WIDTH-1];
MUXF7 fpga_hard_mux (.I0(T0), .I1(T1), .S(B[B_WIDTH-1]), .O(Y));
end
else if (B_WIDTH == 4) begin
localparam a_width0 = 2 ** 2;
localparam num_mux8 = A_WIDTH / a_width0;
localparam a_widthN = A_WIDTH - num_mux8*a_width0;
wire [4-1:0] T;
wire T0, T1;
for (i = 0; i < 4; i++)
if (i < num_mux8)
\$shiftx #(.A_SIGNED(A_SIGNED), .B_SIGNED(B_SIGNED), .A_WIDTH(a_width0), .B_WIDTH(2), .Y_WIDTH(Y_WIDTH)) fpga_soft_mux (.A(A[i*a_width0+:a_width0]), .B(B[2-1:0]), .Y(T[i]));
else if (i == num_mux8 && a_widthN > 0) begin
if (a_widthN > 1)
\$shiftx #(.A_SIGNED(A_SIGNED), .B_SIGNED(B_SIGNED), .A_WIDTH(a_widthN), .B_WIDTH($clog2(a_widthN)), .Y_WIDTH(Y_WIDTH)) fpga_soft_mux_last (.A(A[A_WIDTH-1:i*a_width0]), .B(B[$clog2(a_widthN)-1:0]), .Y(T[i]));
else
assign T[i] = A[A_WIDTH-1];
end
else
assign T[i] = 1'bx;
MUXF7 fpga_hard_mux_0 (.I0(T[0]), .I1(T[1]), .S(B[2]), .O(T0));
MUXF7 fpga_hard_mux_1 (.I0(T[2]), .I1(T[3]), .S(B[2]), .O(T1));
MUXF8 fpga_hard_mux_2 (.I0(T0), .I1(T1), .S(B[3]), .O(Y));
end
else begin
localparam a_width0 = 2 ** 4;
localparam num_mux16 = A_WIDTH / a_width0;
localparam a_widthN = A_WIDTH - num_mux16*a_width0;
wire [(2**(B_WIDTH-4))-1:0] T;
for (i = 0; i < 2 ** (B_WIDTH-4); i++)
if (i < num_mux16)
\$__XILINX_SHIFTX #(.A_SIGNED(A_SIGNED), .B_SIGNED(B_SIGNED), .A_WIDTH(a_width0), .B_WIDTH(4), .Y_WIDTH(Y_WIDTH)) fpga_soft_mux (.A(A[i*a_width0+:a_width0]), .B(B[4-1:0]), .Y(T[i]));
else if (i == num_mux16 && a_widthN > 0) begin
if (a_widthN > 1)
\$__XILINX_SHIFTX #(.A_SIGNED(A_SIGNED), .B_SIGNED(B_SIGNED), .A_WIDTH(a_widthN), .B_WIDTH($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;
\$__XILINX_SHIFTX #(.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
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_SHIFTX #(.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_SHIFTX #(.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

52
techlibs/xilinx/mux_map.v Normal file
View file

@ -0,0 +1,52 @@
/*
* 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
* 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.
*
*/
module \$shiftx (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 [B_WIDTH-1:0] _TECHMAP_CONSTMSK_B_ = 0;
parameter [B_WIDTH-1:0] _TECHMAP_CONSTVAL_B_ = 0;
generate
genvar i, j;
// TODO: Check if this opt still necessary
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
\$__XILINX_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;
end
else if (B_WIDTH < 3 || A_WIDTH <= 4) begin
wire _TECHMAP_FAIL_ = 1;
end
else begin
\$__XILINX_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
endgenerate
endmodule

24
techlibs/xilinx/synth_xilinx.cc
View file

@ -72,6 +72,9 @@ struct SynthXilinxPass : public ScriptPass
log(" -nosrl\n");
log(" disable inference of shift registers\n");
log("\n");
log(" -nomux\n");
log(" disable inference of wide multiplexers\n");
log("\n");
log(" -run <from_label>:<to_label>\n");
log(" only run the commands between the labels (see below). an empty\n");
log(" from label is synonymous to 'begin', and empty to label is\n");
@ -93,7 +96,7 @@ struct SynthXilinxPass : public ScriptPass
}
std::string top_opt, edif_file, blif_file, abc, arch;
bool flatten, retime, vpr, nocarry, nobram, nodram, nosrl;
bool flatten, retime, vpr, nocarry, nobram, nodram, nosrl, nomux;
void clear_flags() YS_OVERRIDE
{
@ -108,6 +111,7 @@ struct SynthXilinxPass : public ScriptPass
nobram = false;
nodram = false;
nosrl = false;
nomux = false;
arch = "xc7";
}
@ -171,6 +175,10 @@ struct SynthXilinxPass : public ScriptPass
nosrl = true;
continue;
}
if (args[argidx] == "-nomux") {
nomux = true;
continue;
}
if (args[argidx] == "-abc9") {
abc = "abc9";
continue;
@ -219,11 +227,15 @@ struct SynthXilinxPass : public ScriptPass
if (check_label("coarse")) {
run("synth -run coarse");
//if (!nomux || help_mode)
// run("muxpack", "(skip if '-nomux')");
// shregmap -tech xilinx can cope with $shiftx and $mux
// cells for identifying variable-length shift registers,
// so attempt to convert $pmux-es to the former
if (!nosrl || help_mode)
run("pmux2shiftx", "(skip if '-nosrl')");
// Also: wide multiplexer inference benefits from this too
if (!(nosrl && nomux) || help_mode)
run("pmux2shiftx", "(skip if '-nosrl' and '-nomux')");
// Run a number of peephole optimisations, including one
// that optimises $mul cells driving $shiftx's B input
@ -261,6 +273,10 @@ struct SynthXilinxPass : public ScriptPass
}
std::string techmap_files = " -map +/techmap.v";
if (help_mode)
techmap_files += " [-map +/xilinx/mux_map.v]";
else if (!nomux)
techmap_files += " -map +/xilinx/mux_map.v";
if (help_mode)
techmap_files += " [-map +/xilinx/arith_map.v]";
else if (!nocarry) {
@ -275,6 +291,8 @@ struct SynthXilinxPass : public ScriptPass
}
if (check_label("map_cells")) {
if (!nomux || help_mode)
run("muxcover -mux8 -mux16", "(skip if '-nomux')");
run("techmap -map +/techmap.v -map +/xilinx/cells_map.v");
run("clean");
}