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Extend during mux decomposition with 1'bx

This commit is contained in:
Eddie Hung 2019-07-09 10:59:37 -07:00
parent c864995343
commit 93522b0ae1
1 changed files with 3 additions and 24 deletions
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27
techlibs/xilinx/cells_map.v
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@ -203,25 +203,11 @@ module \$__XILINX_SHIFTX (A, B, Y);
MUXF7 fpga_hard_mux (.I0(A[0]), .I1(A[1]), .S(B[0]), .O(Y)); MUXF7 fpga_hard_mux (.I0(A[0]), .I1(A[1]), .S(B[0]), .O(Y));
end end
else if (A_WIDTH <= 4) begin else if (A_WIDTH <= 4) begin
// Rather than extend with 1'bx which gets flattened to 1'b0 wire [4-1:0] Ax = {{{4-A_WIDTH}{1'bx}}, A};
// causing the "don't care" status to get lost, extend with MSBs
// so that we can recognise again later when mapping MUXF78
wire [4-1:0] Ax;
if (A_WIDTH == 4)
assign Ax = A;
else
assign Ax = {A[1-:4-A_WIDTH], A};
\$__XILINX_MUXF78 fpga_hard_mux (.I0(Ax[0]), .I1(Ax[2]), .I2(Ax[1]), .I3(Ax[3]), .S0(B[1]), .S1(B[0]), .O(Y)); \$__XILINX_MUXF78 fpga_hard_mux (.I0(Ax[0]), .I1(Ax[2]), .I2(Ax[1]), .I3(Ax[3]), .S0(B[1]), .S1(B[0]), .O(Y));
end end
else if (A_WIDTH <= 8) begin else if (A_WIDTH <= 8) begin
// Rather than extend with 1'bx which gets flattened to 1'b0 wire [8-1:0] Ax = {{{8-A_WIDTH}{1'bx}}, A};
// causing the "don't care" status to get lost, extend with MSBs
// so that we can recognise again later when mapping MUXF78
wire [8-1:0] Ax;
if (A_WIDTH == 8)
assign Ax = A;
else
assign Ax = {A[3-:8-A_WIDTH], A};
wire T0 = B[2] ? Ax[4] : Ax[0]; wire T0 = B[2] ? Ax[4] : Ax[0];
wire T1 = B[2] ? Ax[5] : Ax[1]; wire T1 = B[2] ? Ax[5] : Ax[1];
wire T2 = B[2] ? Ax[6] : Ax[2]; wire T2 = B[2] ? Ax[6] : Ax[2];
@ -229,14 +215,7 @@ module \$__XILINX_SHIFTX (A, B, Y);
\$__XILINX_MUXF78 fpga_hard_mux (.I0(T0), .I1(T2), .I2(T1), .I3(T3), .S0(B[1]), .S1(B[0]), .O(Y)); \$__XILINX_MUXF78 fpga_hard_mux (.I0(T0), .I1(T2), .I2(T1), .I3(T3), .S0(B[1]), .S1(B[0]), .O(Y));
end end
else if (A_WIDTH <= 16) begin else if (A_WIDTH <= 16) begin
// Rather than extend with 1'bx which gets flattened to 1'b0 wire [16-1:0] Ax = {{{16-A_WIDTH}{1'bx}}, A};
// causing the "don't care" status to get lost, extend with MSBs
// so that we can recognise again later when mapping MUXF78
wire [16-1:0] Ax;
if (A_WIDTH == 16)
assign Ax = A;
else
assign Ax = {A[7-:16-A_WIDTH], A};
wire T0 = B[2] ? B[3] ? Ax[12] : Ax[4] wire T0 = B[2] ? B[3] ? Ax[12] : Ax[4]
: B[3] ? Ax[ 8] : Ax[0]; : B[3] ? Ax[ 8] : Ax[0];
wire T1 = B[2] ? B[3] ? Ax[13] : Ax[5] wire T1 = B[2] ? B[3] ? Ax[13] : Ax[5]