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Add force_downto and force_upto wire attributes.

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Fixes #2058.
This commit is contained in:
Marcelina Kościelnicka 2020-05-18 18:15:03 +02:00
parent 2d573a0ff6
commit aee439360b
43 changed files with 258 additions and 27 deletions
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23
techlibs/xilinx/arith_map.v
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@ -24,9 +24,11 @@
module _80_xilinx_lcu (P, G, CI, CO);
parameter WIDTH = 2;
(* force_downto *)
input [WIDTH-1:0] P, G;
input CI;
(* force_downto *)
output [WIDTH-1:0] CO;
wire _TECHMAP_FAIL_ = WIDTH <= 2;
@ -41,7 +43,9 @@ module _80_xilinx_lcu (P, G, CI, CO);
generate if (EXPLICIT_CARRY || `LUT_SIZE == 4) begin
(* force_downto *)
wire [WIDTH-1:0] C = {CO, CI};
(* force_downto *)
wire [WIDTH-1:0] S = P & ~G;
generate for (i = 0; i < WIDTH; i = i + 1) begin:slice
@ -59,8 +63,11 @@ end else begin
localparam MAX_WIDTH = CARRY4_COUNT * 4;
localparam PAD_WIDTH = MAX_WIDTH - WIDTH;
(* force_downto *)
wire [MAX_WIDTH-1:0] S = {{PAD_WIDTH{1'b0}}, P & ~G};
(* force_downto *)
wire [MAX_WIDTH-1:0] GG = {{PAD_WIDTH{1'b0}}, G};
(* force_downto *)
wire [MAX_WIDTH-1:0] C;
assign CO = C;
@ -103,20 +110,27 @@ module _80_xilinx_alu (A, B, CI, BI, X, Y, CO);
parameter _TECHMAP_CONSTVAL_CI_ = 0;
parameter _TECHMAP_CONSTMSK_CI_ = 0;
(* force_downto *)
input [A_WIDTH-1:0] A;
(* force_downto *)
input [B_WIDTH-1:0] B;
(* force_downto *)
output [Y_WIDTH-1:0] X, Y;
input CI, BI;
(* force_downto *)
output [Y_WIDTH-1:0] CO;
wire _TECHMAP_FAIL_ = Y_WIDTH <= 2;
(* force_downto *)
wire [Y_WIDTH-1:0] A_buf, B_buf;
\$pos #(.A_SIGNED(A_SIGNED), .A_WIDTH(A_WIDTH), .Y_WIDTH(Y_WIDTH)) A_conv (.A(A), .Y(A_buf));
\$pos #(.A_SIGNED(B_SIGNED), .A_WIDTH(B_WIDTH), .Y_WIDTH(Y_WIDTH)) B_conv (.A(B), .Y(B_buf));
(* force_downto *)
wire [Y_WIDTH-1:0] AA = A_buf;
(* force_downto *)
wire [Y_WIDTH-1:0] BB = BI ? ~B_buf : B_buf;
genvar i;
@ -129,7 +143,9 @@ module _80_xilinx_alu (A, B, CI, BI, X, Y, CO);
generate if (`LUT_SIZE == 4) begin
(* force_downto *)
wire [Y_WIDTH-1:0] C = {CO, CI};
(* force_downto *)
wire [Y_WIDTH-1:0] S = {AA ^ BB};
genvar i;
@ -149,6 +165,7 @@ generate if (`LUT_SIZE == 4) begin
end else if (EXPLICIT_CARRY) begin
(* force_downto *)
wire [Y_WIDTH-1:0] S = AA ^ BB;
wire CINIT;
@ -161,7 +178,9 @@ end else if (EXPLICIT_CARRY) begin
// So we maintain two wire sets, CO_CHAIN is the carry that is for VPR,
// e.g. off fabric dedicated chain. CO is the carry outputs that are
// available to the fabric.
(* force_downto *)
wire [Y_WIDTH-1:0] CO_CHAIN;
(* force_downto *)
wire [Y_WIDTH-1:0] C = {CO_CHAIN, CINIT};
// If carry chain is being initialized to a constant, techmap the constant
@ -250,10 +269,14 @@ end else begin
localparam MAX_WIDTH = CARRY4_COUNT * 4;
localparam PAD_WIDTH = MAX_WIDTH - Y_WIDTH;
(* force_downto *)
wire [MAX_WIDTH-1:0] S = {{PAD_WIDTH{1'b0}}, AA ^ BB};
(* force_downto *)
wire [MAX_WIDTH-1:0] DI = {{PAD_WIDTH{1'b0}}, AA};
(* force_downto *)
wire [MAX_WIDTH-1:0] O;
(* force_downto *)
wire [MAX_WIDTH-1:0] C;
assign Y = O, CO = C;