Merge pull request #7 from YosysHQ/master

Syncing with official repo

8 files changed, 497 insertions, 30 deletions

diff --git a/techlibs/common/Makefile.inc b/techlibs/common/Makefile.inc
index ab961ac0b..de94798af 100644
--- a/techlibs/common/Makefile.inc
+++ b/techlibs/common/Makefile.inc
@@ -25,5 +25,7 @@ $(eval $(call add_share_file,share,techlibs/common/techmap.v))
 $(eval $(call add_share_file,share,techlibs/common/pmux2mux.v))
 $(eval $(call add_share_file,share,techlibs/common/adff2dff.v))
 $(eval $(call add_share_file,share,techlibs/common/dff2ff.v))
+$(eval $(call add_share_file,share,techlibs/common/gate2lut.v))
+$(eval $(call add_share_file,share,techlibs/common/cmp2lut.v))
 $(eval $(call add_share_file,share,techlibs/common/cells.lib))
-
+$(eval $(call add_share_file,share,techlibs/common/dummy.box))
diff --git a/techlibs/common/cmp2lut.v b/techlibs/common/cmp2lut.v
new file mode 100644
index 000000000..0d0757767
--- /dev/null
+++ b/techlibs/common/cmp2lut.v
@@ -0,0 +1,105 @@
+// Certain arithmetic operations between a signal of width n and a constant can be directly mapped
+// to a single k-LUT (where n <= k). This is preferable to normal alumacc techmapping process
+// because for many targets, arithmetic techmapping creates hard logic (such as carry cells) which often
+// cannot be optimized further.
+//
+// TODO: Currently, only comparisons with 1-bit output are mapped. Potentially, all arithmetic cells
+// with n <= k inputs should be techmapped in this way, because this shortens the critical path
+// from n to 1 by avoiding carry chains.
+
+(* techmap_celltype = "$eq $ne $lt $le $gt $ge" *)
+module _90_lut_cmp_ (A, B, Y);
+
+parameter A_SIGNED = 0;
+parameter B_SIGNED = 0;
+parameter A_WIDTH = 0;
+parameter B_WIDTH = 0;
+parameter Y_WIDTH = 0;
+
+input [A_WIDTH-1:0] A;
+input [B_WIDTH-1:0] B;
+output [Y_WIDTH-1:0] Y;
+
+parameter _TECHMAP_CELLTYPE_ = "";
+
+parameter _TECHMAP_CONSTMSK_A_ = 0;
+parameter _TECHMAP_CONSTVAL_A_ = 0;
+parameter _TECHMAP_CONSTMSK_B_ = 0;
+parameter _TECHMAP_CONSTVAL_B_ = 0;
+
+function automatic [(1 << `LUT_WIDTH)-1:0] gen_lut;
+	input integer width;
+	input integer operation;
+	input integer swap;
+	input integer sign;
+	input integer operand;
+	integer n, i_var, i_cst, lhs, rhs, o_bit;
+	begin
+		gen_lut = width'b0;
+		for (n = 0; n < (1 << width); n++) begin
+			if (sign)
+				i_var = n[width-1:0];
+			else
+				i_var = n;
+			i_cst = operand;
+			if (swap) begin
+				lhs = i_cst;
+				rhs = i_var;
+			end else begin
+				lhs = i_var;
+				rhs = i_cst;
+			end
+			if (operation == 0)
+				o_bit = (lhs <  rhs);
+			if (operation == 1)
+				o_bit = (lhs <= rhs);
+			if (operation == 2)
+				o_bit = (lhs >  rhs);
+			if (operation == 3)
+				o_bit = (lhs >= rhs);
+			if (operation == 4)
+				o_bit = (lhs == rhs);
+			if (operation == 5)
+				o_bit = (lhs != rhs);
+			gen_lut = gen_lut | (o_bit << n);
+		end
+	end
+endfunction
+
+generate
+	if (_TECHMAP_CELLTYPE_ == "$lt")
+		localparam operation = 0;
+	if (_TECHMAP_CELLTYPE_ == "$le")
+		localparam operation = 1;
+	if (_TECHMAP_CELLTYPE_ == "$gt")
+		localparam operation = 2;
+	if (_TECHMAP_CELLTYPE_ == "$ge")
+		localparam operation = 3;
+	if (_TECHMAP_CELLTYPE_ == "$eq")
+		localparam operation = 4;
+	if (_TECHMAP_CELLTYPE_ == "$ne")
+		localparam operation = 5;
+
+	if (A_WIDTH > `LUT_WIDTH || B_WIDTH > `LUT_WIDTH || Y_WIDTH != 1)
+		wire _TECHMAP_FAIL_ = 1;
+	else if (&_TECHMAP_CONSTMSK_B_)
+		\$lut #(
+			.WIDTH(A_WIDTH),
+			.LUT({ gen_lut(A_WIDTH, operation, 0, A_SIGNED && B_SIGNED, _TECHMAP_CONSTVAL_B_) })
+		) _TECHMAP_REPLACE_ (
+			.A(A),
+			.Y(Y)
+		);
+	else if (&_TECHMAP_CONSTMSK_A_)
+		\$lut #(
+			.WIDTH(B_WIDTH),
+			.LUT({ gen_lut(B_WIDTH, operation, 1, A_SIGNED && B_SIGNED, _TECHMAP_CONSTVAL_A_) })
+		) _TECHMAP_REPLACE_ (
+			.A(B),
+			.Y(Y)
+		);
+	else
+		wire _TECHMAP_FAIL_ = 1;
+endgenerate
+
+endmodule
diff --git a/techlibs/common/dummy.box b/techlibs/common/dummy.box
new file mode 100644
index 000000000..0c18070a0
--- /dev/null
+++ b/techlibs/common/dummy.box
@@ -0,0 +1 @@
+(dummy) 1 0 0 0
diff --git a/techlibs/common/gate2lut.v b/techlibs/common/gate2lut.v
new file mode 100644
index 000000000..99c123f4a
--- /dev/null
+++ b/techlibs/common/gate2lut.v
@@ -0,0 +1,87 @@
+(* techmap_celltype = "$_NOT_" *)
+module _90_lut_not (A, Y);
+    input A;
+    output Y;
+
+    wire [`LUT_WIDTH-1:0] AA;
+    assign AA = {A};
+
+    \$lut #(
+        .WIDTH(`LUT_WIDTH),
+        .LUT(4'b01)
+    ) lut (
+        .A(AA),
+        .Y(Y)
+    );
+endmodule
+
+(* techmap_celltype = "$_OR_" *)
+module _90_lut_or (A, B, Y);
+    input A, B;
+    output Y;
+
+    wire [`LUT_WIDTH-1:0] AA;
+    assign AA = {B, A};
+
+    \$lut #(
+        .WIDTH(`LUT_WIDTH),
+        .LUT(4'b1110)
+    ) lut (
+        .A(AA),
+        .Y(Y)
+    );
+endmodule
+
+(* techmap_celltype = "$_AND_" *)
+module _90_lut_and (A, B, Y);
+    input A, B;
+    output Y;
+
+    wire [`LUT_WIDTH-1:0] AA;
+    assign AA = {B, A};
+
+    \$lut #(
+        .WIDTH(`LUT_WIDTH),
+        .LUT(4'b1000)
+    ) lut (
+        .A(AA),
+        .Y(Y)
+    );
+endmodule
+
+(* techmap_celltype = "$_XOR_" *)
+module _90_lut_xor (A, B, Y);
+    input A, B;
+    output Y;
+
+    wire [`LUT_WIDTH-1:0] AA;
+    assign AA = {B, A};
+
+    \$lut #(
+        .WIDTH(`LUT_WIDTH),
+        .LUT(4'b0110)
+    ) lut (
+        .A(AA),
+        .Y(Y)
+    );
+endmodule
+
+(* techmap_celltype = "$_MUX_" *)
+module _90_lut_mux (A, B, S, Y);
+    input A, B, S;
+    output Y;
+
+    wire [`LUT_WIDTH-1:0] AA;
+    assign AA = {S, B, A};
+
+    \$lut #(
+        .WIDTH(`LUT_WIDTH),
+        //     A 1010 1010
+        //     B 1100 1100
+        //     S 1111 0000
+        .LUT(8'b_1100_1010)
+    ) lut (
+        .A(AA),
+        .Y(Y)
+    );
+endmodule
diff --git a/techlibs/common/prep.cc b/techlibs/common/prep.cc
index cc977f97e..cdd21c3b3 100644
--- a/techlibs/common/prep.cc
+++ b/techlibs/common/prep.cc
@@ -29,7 +29,7 @@ struct PrepPass : public ScriptPass
 {
 	PrepPass() : ScriptPass("prep", "generic synthesis script") { }
 
-	virtual void help() YS_OVERRIDE
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -81,7 +81,7 @@ struct PrepPass : public ScriptPass
 	string top_module, fsm_opts;
 	bool autotop, flatten, ifxmode, memxmode, nomemmode, nokeepdc, nordff;
 
-	virtual void clear_flags() YS_OVERRIDE
+	void clear_flags() YS_OVERRIDE
 	{
 		top_module.clear();
 
@@ -94,7 +94,7 @@ struct PrepPass : public ScriptPass
 		nordff = true;
 	}
 
-	virtual void execute(std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
+	void execute(std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
 	{
 		string run_from, run_to;
 
@@ -153,7 +153,7 @@ struct PrepPass : public ScriptPass
 		extra_args(args, argidx, design);
 
 		if (!design->full_selection())
-			log_cmd_error("This comannd only operates on fully selected designs!\n");
+			log_cmd_error("This command only operates on fully selected designs!\n");
 
 		log_header(design, "Executing PREP pass.\n");
 		log_push();
@@ -163,7 +163,7 @@ struct PrepPass : public ScriptPass
 		log_pop();
 	}
 
-	virtual void script() YS_OVERRIDE
+	void script() YS_OVERRIDE
 	{
 
 		if (check_label("begin"))
@@ -195,9 +195,11 @@ struct PrepPass : public ScriptPass
 			run(nokeepdc ? "opt" : "opt -keepdc");
 			if (!ifxmode) {
 				if (help_mode)
-					run("wreduce [-memx]");
-				else
+					run("wreduce -keepdc [-memx]");
+				else if (nokeepdc)
 					run(memxmode ? "wreduce -memx" : "wreduce");
+				else
+					run(memxmode ? "wreduce -keepdc -memx" : "wreduce -keepdc");
 			}
 			if (!nomemmode) {
 				run(string("memory_dff") + (help_mode ? " [-nordff]" : nordff ? " -nordff" : ""));
diff --git a/techlibs/common/simcells.v b/techlibs/common/simcells.v
index 937512e7c..64720e598 100644
--- a/techlibs/common/simcells.v
+++ b/techlibs/common/simcells.v
@@ -230,6 +230,25 @@ endmodule
 
 //  |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 //-
+//-     $_NMUX_ (A, B, S, Y)
+//-
+//- A 2-input inverting MUX gate.
+//-
+//- Truth table:    A B S | Y
+//-                -------+---
+//-                 0 - 0 | 1
+//-                 1 - 0 | 0
+//-                 - 0 1 | 1
+//-                 - 1 1 | 0
+//-
+module \$_NMUX_ (A, B, S, Y);
+input A, B, S;
+output Y;
+assign Y = S ? !B : !A;
+endmodule
+
+//  |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
+//-
 //-     $_MUX4_ (A, B, C, D, S, T, Y)
 //-
 //- A 4-input MUX gate.
@@ -465,7 +484,7 @@ endmodule
 //-
 //-     $_SR_NP_ (S, R, Q)
 //-
-//- A set-reset latch with negative polarity SET and positive polarioty RESET.
+//- A set-reset latch with negative polarity SET and positive polarity RESET.
 //-
 //- Truth table:    S R | Q
 //-                -----+---
@@ -489,7 +508,7 @@ endmodule
 //-
 //-     $_SR_PN_ (S, R, Q)
 //-
-//- A set-reset latch with positive polarity SET and negative polarioty RESET.
+//- A set-reset latch with positive polarity SET and negative polarity RESET.
 //-
 //- Truth table:    S R | Q
 //-                -----+---
diff --git a/techlibs/common/simlib.v b/techlibs/common/simlib.v
index 8e43fe058..7845a3fed 100644
--- a/techlibs/common/simlib.v
+++ b/techlibs/common/simlib.v
@@ -532,14 +532,26 @@ endmodule
 
 // --------------------------------------------------------
 
+//  |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
+//-
+//-     $lcu (P, G, CI, CO)
+//-
+//- Lookahead carry unit
+//- A building block dedicated to fast computation of carry-bits used in binary
+//- arithmetic operations. By replacing the ripple carry structure used in full-adder
+//- blocks, the more significant  bits of the sum can be expected to be computed more
+//- quickly.
+//- Typically created during `techmap` of $alu cells (see the "_90_alu" rule in
+//- +/techmap.v).
 module \$lcu (P, G, CI, CO);
 
 parameter WIDTH = 1;
 
-input [WIDTH-1:0] P, G;
-input CI;
+input [WIDTH-1:0] P;    // Propagate
+input [WIDTH-1:0] G;    // Generate
+input CI;               // Carry-in
 
-output reg [WIDTH-1:0] CO;
+output reg [WIDTH-1:0] CO; // Carry-out
 
 integer i;
 always @* begin
@@ -555,6 +567,17 @@ endmodule
 
 // --------------------------------------------------------
 
+//  |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
+//-
+//-     $alu (A, B, CI, BI, X, Y, CO)
+//-
+//- Arithmetic logic unit.
+//- A building block supporting both binary addition/subtraction operations, and
+//- indirectly, comparison operations.
+//- Typically created by the `alumacc` pass, which transforms:
+//-   $add, $sub, $lt, $le, $ge, $gt, $eq, $eqx, $ne, $nex
+//- cells into this $alu cell.
+//-
 module \$alu (A, B, CI, BI, X, Y, CO);
 
 parameter A_SIGNED = 0;
@@ -563,12 +586,16 @@ 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] X, Y;
+input [A_WIDTH-1:0] A;      // Input operand
+input [B_WIDTH-1:0] B;      // Input operand
+output [Y_WIDTH-1:0] X;     // A xor B (sign-extended, optional B inversion,
+                            //          used in combination with
+                            //          reduction-AND for $eq/$ne ops)
+output [Y_WIDTH-1:0] Y;     // Sum
 
-input CI, BI;
-output [Y_WIDTH-1:0] CO;
+input CI;                   // Carry-in (set for $sub)
+input BI;                   // Invert-B (set for $sub)
+output [Y_WIDTH-1:0] CO;    // Carry-out
 
 wire [Y_WIDTH-1:0] AA, BB;
 
@@ -584,6 +611,7 @@ endgenerate
 wire y_co_undef = ^{A, A, B, B, CI, CI, BI, BI};
 
 assign X = AA ^ BB;
+// Full adder
 assign Y = (AA + BB + CI) ^ {Y_WIDTH{y_co_undef}};
 
 function get_carry;
@@ -1271,6 +1299,181 @@ endmodule
 
 // --------------------------------------------------------
 
+module \$specify2 (EN, SRC, DST);
+
+parameter FULL = 0;
+parameter SRC_WIDTH = 1;
+parameter DST_WIDTH = 1;
+
+parameter SRC_DST_PEN = 0;
+parameter SRC_DST_POL = 0;
+
+parameter T_RISE_MIN = 0;
+parameter T_RISE_TYP = 0;
+parameter T_RISE_MAX = 0;
+
+parameter T_FALL_MIN = 0;
+parameter T_FALL_TYP = 0;
+parameter T_FALL_MAX = 0;
+
+input EN;
+input [SRC_WIDTH-1:0] SRC;
+input [DST_WIDTH-1:0] DST;
+
+localparam SD = SRC_DST_PEN ? (SRC_DST_POL ? 1 : 2) : 0;
+
+`ifdef SIMLIB_SPECIFY
+specify
+	if (EN && SD==0 && !FULL) (SRC  => DST) = (T_RISE_MIN:T_RISE_TYP:T_RISE_MAX, T_FALL_MIN:T_FALL_TYP:T_FALL_MAX);
+	if (EN && SD==0 &&  FULL) (SRC  *> DST) = (T_RISE_MIN:T_RISE_TYP:T_RISE_MAX, T_FALL_MIN:T_FALL_TYP:T_FALL_MAX);
+	if (EN && SD==1 && !FULL) (SRC +=> DST) = (T_RISE_MIN:T_RISE_TYP:T_RISE_MAX, T_FALL_MIN:T_FALL_TYP:T_FALL_MAX);
+	if (EN && SD==1 &&  FULL) (SRC +*> DST) = (T_RISE_MIN:T_RISE_TYP:T_RISE_MAX, T_FALL_MIN:T_FALL_TYP:T_FALL_MAX);
+	if (EN && SD==2 && !FULL) (SRC -=> DST) = (T_RISE_MIN:T_RISE_TYP:T_RISE_MAX, T_FALL_MIN:T_FALL_TYP:T_FALL_MAX);
+	if (EN && SD==2 &&  FULL) (SRC -*> DST) = (T_RISE_MIN:T_RISE_TYP:T_RISE_MAX, T_FALL_MIN:T_FALL_TYP:T_FALL_MAX);
+endspecify
+`endif
+
+endmodule
+
+// --------------------------------------------------------
+
+module \$specify3 (EN, SRC, DST, DAT);
+
+parameter FULL = 0;
+parameter SRC_WIDTH = 1;
+parameter DST_WIDTH = 1;
+
+parameter EDGE_EN = 0;
+parameter EDGE_POL = 0;
+
+parameter SRC_DST_PEN = 0;
+parameter SRC_DST_POL = 0;
+
+parameter DAT_DST_PEN = 0;
+parameter DAT_DST_POL = 0;
+
+parameter T_RISE_MIN = 0;
+parameter T_RISE_TYP = 0;
+parameter T_RISE_MAX = 0;
+
+parameter T_FALL_MIN = 0;
+parameter T_FALL_TYP = 0;
+parameter T_FALL_MAX = 0;
+
+input EN;
+input [SRC_WIDTH-1:0] SRC;
+input [DST_WIDTH-1:0] DST, DAT;
+
+localparam ED = EDGE_EN     ? (EDGE_POL    ? 1 : 2) : 0;
+localparam SD = SRC_DST_PEN ? (SRC_DST_POL ? 1 : 2) : 0;
+localparam DD = DAT_DST_PEN ? (DAT_DST_POL ? 1 : 2) : 0;
+
+`ifdef SIMLIB_SPECIFY
+specify
+	// DD=0
+
+	if (EN && DD==0 && SD==0 && ED==0 && !FULL) (        SRC  => (DST  : DAT)) = (T_RISE_MIN:T_RISE_TYP:T_RISE_MAX, T_FALL_MIN:T_FALL_TYP:T_FALL_MAX);
+	if (EN && DD==0 && SD==0 && ED==0 &&  FULL) (        SRC  *> (DST  : DAT)) = (T_RISE_MIN:T_RISE_TYP:T_RISE_MAX, T_FALL_MIN:T_FALL_TYP:T_FALL_MAX);
+	if (EN && DD==0 && SD==0 && ED==1 && !FULL) (posedge SRC  => (DST  : DAT)) = (T_RISE_MIN:T_RISE_TYP:T_RISE_MAX, T_FALL_MIN:T_FALL_TYP:T_FALL_MAX);
+	if (EN && DD==0 && SD==0 && ED==1 &&  FULL) (posedge SRC  *> (DST  : DAT)) = (T_RISE_MIN:T_RISE_TYP:T_RISE_MAX, T_FALL_MIN:T_FALL_TYP:T_FALL_MAX);
+	if (EN && DD==0 && SD==0 && ED==2 && !FULL) (negedge SRC  => (DST  : DAT)) = (T_RISE_MIN:T_RISE_TYP:T_RISE_MAX, T_FALL_MIN:T_FALL_TYP:T_FALL_MAX);
+	if (EN && DD==0 && SD==0 && ED==2 &&  FULL) (negedge SRC  *> (DST  : DAT)) = (T_RISE_MIN:T_RISE_TYP:T_RISE_MAX, T_FALL_MIN:T_FALL_TYP:T_FALL_MAX);
+
+	if (EN && DD==0 && SD==1 && ED==0 && !FULL) (        SRC +=> (DST  : DAT)) = (T_RISE_MIN:T_RISE_TYP:T_RISE_MAX, T_FALL_MIN:T_FALL_TYP:T_FALL_MAX);
+	if (EN && DD==0 && SD==1 && ED==0 &&  FULL) (        SRC +*> (DST  : DAT)) = (T_RISE_MIN:T_RISE_TYP:T_RISE_MAX, T_FALL_MIN:T_FALL_TYP:T_FALL_MAX);
+	if (EN && DD==0 && SD==1 && ED==1 && !FULL) (posedge SRC +=> (DST  : DAT)) = (T_RISE_MIN:T_RISE_TYP:T_RISE_MAX, T_FALL_MIN:T_FALL_TYP:T_FALL_MAX);
+	if (EN && DD==0 && SD==1 && ED==1 &&  FULL) (posedge SRC +*> (DST  : DAT)) = (T_RISE_MIN:T_RISE_TYP:T_RISE_MAX, T_FALL_MIN:T_FALL_TYP:T_FALL_MAX);
+	if (EN && DD==0 && SD==1 && ED==2 && !FULL) (negedge SRC +=> (DST  : DAT)) = (T_RISE_MIN:T_RISE_TYP:T_RISE_MAX, T_FALL_MIN:T_FALL_TYP:T_FALL_MAX);
+	if (EN && DD==0 && SD==1 && ED==2 &&  FULL) (negedge SRC +*> (DST  : DAT)) = (T_RISE_MIN:T_RISE_TYP:T_RISE_MAX, T_FALL_MIN:T_FALL_TYP:T_FALL_MAX);
+
+	if (EN && DD==0 && SD==2 && ED==0 && !FULL) (        SRC -=> (DST  : DAT)) = (T_RISE_MIN:T_RISE_TYP:T_RISE_MAX, T_FALL_MIN:T_FALL_TYP:T_FALL_MAX);
+	if (EN && DD==0 && SD==2 && ED==0 &&  FULL) (        SRC -*> (DST  : DAT)) = (T_RISE_MIN:T_RISE_TYP:T_RISE_MAX, T_FALL_MIN:T_FALL_TYP:T_FALL_MAX);
+	if (EN && DD==0 && SD==2 && ED==1 && !FULL) (posedge SRC -=> (DST  : DAT)) = (T_RISE_MIN:T_RISE_TYP:T_RISE_MAX, T_FALL_MIN:T_FALL_TYP:T_FALL_MAX);
+	if (EN && DD==0 && SD==2 && ED==1 &&  FULL) (posedge SRC -*> (DST  : DAT)) = (T_RISE_MIN:T_RISE_TYP:T_RISE_MAX, T_FALL_MIN:T_FALL_TYP:T_FALL_MAX);
+	if (EN && DD==0 && SD==2 && ED==2 && !FULL) (negedge SRC -=> (DST  : DAT)) = (T_RISE_MIN:T_RISE_TYP:T_RISE_MAX, T_FALL_MIN:T_FALL_TYP:T_FALL_MAX);
+	if (EN && DD==0 && SD==2 && ED==2 &&  FULL) (negedge SRC -*> (DST  : DAT)) = (T_RISE_MIN:T_RISE_TYP:T_RISE_MAX, T_FALL_MIN:T_FALL_TYP:T_FALL_MAX);
+
+	// DD=1
+
+	if (EN && DD==1 && SD==0 && ED==0 && !FULL) (        SRC  => (DST +: DAT)) = (T_RISE_MIN:T_RISE_TYP:T_RISE_MAX, T_FALL_MIN:T_FALL_TYP:T_FALL_MAX);
+	if (EN && DD==1 && SD==0 && ED==0 &&  FULL) (        SRC  *> (DST +: DAT)) = (T_RISE_MIN:T_RISE_TYP:T_RISE_MAX, T_FALL_MIN:T_FALL_TYP:T_FALL_MAX);
+	if (EN && DD==1 && SD==0 && ED==1 && !FULL) (posedge SRC  => (DST +: DAT)) = (T_RISE_MIN:T_RISE_TYP:T_RISE_MAX, T_FALL_MIN:T_FALL_TYP:T_FALL_MAX);
+	if (EN && DD==1 && SD==0 && ED==1 &&  FULL) (posedge SRC  *> (DST +: DAT)) = (T_RISE_MIN:T_RISE_TYP:T_RISE_MAX, T_FALL_MIN:T_FALL_TYP:T_FALL_MAX);
+	if (EN && DD==1 && SD==0 && ED==2 && !FULL) (negedge SRC  => (DST +: DAT)) = (T_RISE_MIN:T_RISE_TYP:T_RISE_MAX, T_FALL_MIN:T_FALL_TYP:T_FALL_MAX);
+	if (EN && DD==1 && SD==0 && ED==2 &&  FULL) (negedge SRC  *> (DST +: DAT)) = (T_RISE_MIN:T_RISE_TYP:T_RISE_MAX, T_FALL_MIN:T_FALL_TYP:T_FALL_MAX);
+
+	if (EN && DD==1 && SD==1 && ED==0 && !FULL) (        SRC +=> (DST +: DAT)) = (T_RISE_MIN:T_RISE_TYP:T_RISE_MAX, T_FALL_MIN:T_FALL_TYP:T_FALL_MAX);
+	if (EN && DD==1 && SD==1 && ED==0 &&  FULL) (        SRC +*> (DST +: DAT)) = (T_RISE_MIN:T_RISE_TYP:T_RISE_MAX, T_FALL_MIN:T_FALL_TYP:T_FALL_MAX);
+	if (EN && DD==1 && SD==1 && ED==1 && !FULL) (posedge SRC +=> (DST +: DAT)) = (T_RISE_MIN:T_RISE_TYP:T_RISE_MAX, T_FALL_MIN:T_FALL_TYP:T_FALL_MAX);
+	if (EN && DD==1 && SD==1 && ED==1 &&  FULL) (posedge SRC +*> (DST +: DAT)) = (T_RISE_MIN:T_RISE_TYP:T_RISE_MAX, T_FALL_MIN:T_FALL_TYP:T_FALL_MAX);
+	if (EN && DD==1 && SD==1 && ED==2 && !FULL) (negedge SRC +=> (DST +: DAT)) = (T_RISE_MIN:T_RISE_TYP:T_RISE_MAX, T_FALL_MIN:T_FALL_TYP:T_FALL_MAX);
+	if (EN && DD==1 && SD==1 && ED==2 &&  FULL) (negedge SRC +*> (DST +: DAT)) = (T_RISE_MIN:T_RISE_TYP:T_RISE_MAX, T_FALL_MIN:T_FALL_TYP:T_FALL_MAX);
+
+	if (EN && DD==1 && SD==2 && ED==0 && !FULL) (        SRC -=> (DST +: DAT)) = (T_RISE_MIN:T_RISE_TYP:T_RISE_MAX, T_FALL_MIN:T_FALL_TYP:T_FALL_MAX);
+	if (EN && DD==1 && SD==2 && ED==0 &&  FULL) (        SRC -*> (DST +: DAT)) = (T_RISE_MIN:T_RISE_TYP:T_RISE_MAX, T_FALL_MIN:T_FALL_TYP:T_FALL_MAX);
+	if (EN && DD==1 && SD==2 && ED==1 && !FULL) (posedge SRC -=> (DST +: DAT)) = (T_RISE_MIN:T_RISE_TYP:T_RISE_MAX, T_FALL_MIN:T_FALL_TYP:T_FALL_MAX);
+	if (EN && DD==1 && SD==2 && ED==1 &&  FULL) (posedge SRC -*> (DST +: DAT)) = (T_RISE_MIN:T_RISE_TYP:T_RISE_MAX, T_FALL_MIN:T_FALL_TYP:T_FALL_MAX);
+	if (EN && DD==1 && SD==2 && ED==2 && !FULL) (negedge SRC -=> (DST +: DAT)) = (T_RISE_MIN:T_RISE_TYP:T_RISE_MAX, T_FALL_MIN:T_FALL_TYP:T_FALL_MAX);
+	if (EN && DD==1 && SD==2 && ED==2 &&  FULL) (negedge SRC -*> (DST +: DAT)) = (T_RISE_MIN:T_RISE_TYP:T_RISE_MAX, T_FALL_MIN:T_FALL_TYP:T_FALL_MAX);
+
+	// DD=2
+
+	if (EN && DD==2 && SD==0 && ED==0 && !FULL) (        SRC  => (DST -: DAT)) = (T_RISE_MIN:T_RISE_TYP:T_RISE_MAX, T_FALL_MIN:T_FALL_TYP:T_FALL_MAX);
+	if (EN && DD==2 && SD==0 && ED==0 &&  FULL) (        SRC  *> (DST -: DAT)) = (T_RISE_MIN:T_RISE_TYP:T_RISE_MAX, T_FALL_MIN:T_FALL_TYP:T_FALL_MAX);
+	if (EN && DD==2 && SD==0 && ED==1 && !FULL) (posedge SRC  => (DST -: DAT)) = (T_RISE_MIN:T_RISE_TYP:T_RISE_MAX, T_FALL_MIN:T_FALL_TYP:T_FALL_MAX);
+	if (EN && DD==2 && SD==0 && ED==1 &&  FULL) (posedge SRC  *> (DST -: DAT)) = (T_RISE_MIN:T_RISE_TYP:T_RISE_MAX, T_FALL_MIN:T_FALL_TYP:T_FALL_MAX);
+	if (EN && DD==2 && SD==0 && ED==2 && !FULL) (negedge SRC  => (DST -: DAT)) = (T_RISE_MIN:T_RISE_TYP:T_RISE_MAX, T_FALL_MIN:T_FALL_TYP:T_FALL_MAX);
+	if (EN && DD==2 && SD==0 && ED==2 &&  FULL) (negedge SRC  *> (DST -: DAT)) = (T_RISE_MIN:T_RISE_TYP:T_RISE_MAX, T_FALL_MIN:T_FALL_TYP:T_FALL_MAX);
+
+	if (EN && DD==2 && SD==1 && ED==0 && !FULL) (        SRC +=> (DST -: DAT)) = (T_RISE_MIN:T_RISE_TYP:T_RISE_MAX, T_FALL_MIN:T_FALL_TYP:T_FALL_MAX);
+	if (EN && DD==2 && SD==1 && ED==0 &&  FULL) (        SRC +*> (DST -: DAT)) = (T_RISE_MIN:T_RISE_TYP:T_RISE_MAX, T_FALL_MIN:T_FALL_TYP:T_FALL_MAX);
+	if (EN && DD==2 && SD==1 && ED==1 && !FULL) (posedge SRC +=> (DST -: DAT)) = (T_RISE_MIN:T_RISE_TYP:T_RISE_MAX, T_FALL_MIN:T_FALL_TYP:T_FALL_MAX);
+	if (EN && DD==2 && SD==1 && ED==1 &&  FULL) (posedge SRC +*> (DST -: DAT)) = (T_RISE_MIN:T_RISE_TYP:T_RISE_MAX, T_FALL_MIN:T_FALL_TYP:T_FALL_MAX);
+	if (EN && DD==2 && SD==1 && ED==2 && !FULL) (negedge SRC +=> (DST -: DAT)) = (T_RISE_MIN:T_RISE_TYP:T_RISE_MAX, T_FALL_MIN:T_FALL_TYP:T_FALL_MAX);
+	if (EN && DD==2 && SD==1 && ED==2 &&  FULL) (negedge SRC +*> (DST -: DAT)) = (T_RISE_MIN:T_RISE_TYP:T_RISE_MAX, T_FALL_MIN:T_FALL_TYP:T_FALL_MAX);
+
+	if (EN && DD==2 && SD==2 && ED==0 && !FULL) (        SRC -=> (DST -: DAT)) = (T_RISE_MIN:T_RISE_TYP:T_RISE_MAX, T_FALL_MIN:T_FALL_TYP:T_FALL_MAX);
+	if (EN && DD==2 && SD==2 && ED==0 &&  FULL) (        SRC -*> (DST -: DAT)) = (T_RISE_MIN:T_RISE_TYP:T_RISE_MAX, T_FALL_MIN:T_FALL_TYP:T_FALL_MAX);
+	if (EN && DD==2 && SD==2 && ED==1 && !FULL) (posedge SRC -=> (DST -: DAT)) = (T_RISE_MIN:T_RISE_TYP:T_RISE_MAX, T_FALL_MIN:T_FALL_TYP:T_FALL_MAX);
+	if (EN && DD==2 && SD==2 && ED==1 &&  FULL) (posedge SRC -*> (DST -: DAT)) = (T_RISE_MIN:T_RISE_TYP:T_RISE_MAX, T_FALL_MIN:T_FALL_TYP:T_FALL_MAX);
+	if (EN && DD==2 && SD==2 && ED==2 && !FULL) (negedge SRC -=> (DST -: DAT)) = (T_RISE_MIN:T_RISE_TYP:T_RISE_MAX, T_FALL_MIN:T_FALL_TYP:T_FALL_MAX);
+	if (EN && DD==2 && SD==2 && ED==2 &&  FULL) (negedge SRC -*> (DST -: DAT)) = (T_RISE_MIN:T_RISE_TYP:T_RISE_MAX, T_FALL_MIN:T_FALL_TYP:T_FALL_MAX);
+endspecify
+`endif
+
+endmodule
+
+// --------------------------------------------------------
+
+module \$specrule (EN_SRC, EN_DST, SRC, DST);
+
+parameter TYPE = "";
+parameter T_LIMIT = 0;
+parameter T_LIMIT2 = 0;
+
+parameter SRC_WIDTH = 1;
+parameter DST_WIDTH = 1;
+
+parameter SRC_PEN = 0;
+parameter SRC_POL = 0;
+
+parameter DST_PEN = 0;
+parameter DST_POL = 0;
+
+input EN_SRC, EN_DST;
+input [SRC_WIDTH-1:0] SRC;
+input [DST_WIDTH-1:0] DST;
+
+`ifdef SIMLIB_SPECIFY
+specify
+	// TBD
+endspecify
+`endif
+
+endmodule
+
+// --------------------------------------------------------
+
 module \$assert (A, EN);
 
 input A, EN;
@@ -1863,4 +2066,5 @@ end
 endmodule
 
 `endif
+
 // --------------------------------------------------------
diff --git a/techlibs/common/synth.cc b/techlibs/common/synth.cc
index 4ca34839e..a176357a7 100644
--- a/techlibs/common/synth.cc
+++ b/techlibs/common/synth.cc
@@ -29,7 +29,7 @@ struct SynthPass : public ScriptPass
 {
 	SynthPass() : ScriptPass("synth", "generic synthesis script") { }
 
-	virtual void help() YS_OVERRIDE
+	void help() YS_OVERRIDE
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
@@ -51,6 +51,9 @@ struct SynthPass : public ScriptPass
 		log("    -encfile <file>\n");
 		log("        passed to 'fsm_recode' via 'fsm'\n");
 		log("\n");
+		log("    -lut <k>\n");
+		log("        perform synthesis for a k-LUT architecture.\n");
+		log("\n");
 		log("    -nofsm\n");
 		log("        do not run FSM optimization\n");
 		log("\n");
@@ -72,16 +75,20 @@ struct SynthPass : public ScriptPass
 		log("        from label is synonymous to 'begin', and empty to label is\n");
 		log("        synonymous to the end of the command list.\n");
 		log("\n");
+		log("    -abc9\n");
+		log("        use new ABC9 flow (EXPERIMENTAL)\n");
+		log("\n");
 		log("\n");
 		log("The following commands are executed by this synthesis command:\n");
 		help_script();
 		log("\n");
 	}
 
-	string top_module, fsm_opts, memory_opts;
+	string top_module, fsm_opts, memory_opts, abc;
 	bool autotop, flatten, noalumacc, nofsm, noabc, noshare;
+	int lut;
 
-	virtual void clear_flags() YS_OVERRIDE
+	void clear_flags() YS_OVERRIDE
 	{
 		top_module.clear();
 		fsm_opts.clear();
@@ -89,13 +96,15 @@ struct SynthPass : public ScriptPass
 
 		autotop = false;
 		flatten = false;
+		lut = 0;
 		noalumacc = false;
 		nofsm = false;
 		noabc = false;
 		noshare = false;
+		abc = "abc";
 	}
 
-	virtual void execute(std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
+	void execute(std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
 	{
 		string run_from, run_to;
 		clear_flags();
@@ -130,6 +139,10 @@ struct SynthPass : public ScriptPass
 				flatten = true;
 				continue;
 			}
+			if (args[argidx] == "-lut") {
+				lut = atoi(args[++argidx].c_str());
+				continue;
+			}
 			if (args[argidx] == "-nofsm") {
 				nofsm = true;
 				continue;
@@ -150,12 +163,19 @@ struct SynthPass : public ScriptPass
 				noshare = true;
 				continue;
 			}
+			if (args[argidx] == "-abc9") {
+				abc = "abc9";
+				continue;
+			}
 			break;
 		}
 		extra_args(args, argidx, design);
 
 		if (!design->full_selection())
-			log_cmd_error("This comannd only operates on fully selected designs!\n");
+			log_cmd_error("This command only operates on fully selected designs!\n");
+
+		if (abc == "abc9" && !lut)
+			log_cmd_error("ABC9 flow only supported for FPGA synthesis (using '-lut' option)\n");
 
 		log_header(design, "Executing SYNTH pass.\n");
 		log_push();
@@ -165,7 +185,7 @@ struct SynthPass : public ScriptPass
 		log_pop();
 	}
 
-	virtual void script() YS_OVERRIDE
+	void script() YS_OVERRIDE
 	{
 		if (check_label("begin"))
 		{
@@ -186,19 +206,25 @@ struct SynthPass : public ScriptPass
 		{
 			run("proc");
 			if (help_mode || flatten)
-				run("flatten", "(if -flatten)");
+				run("flatten", "  (if -flatten)");
 			run("opt_expr");
 			run("opt_clean");
 			run("check");
 			run("opt");
 			run("wreduce");
+			run("peepopt");
+			run("opt_clean");
+			if (help_mode)
+				run("techmap -map +/cmp2lut.v", " (if -lut)");
+			else
+				run(stringf("techmap -map +/cmp2lut.v -D LUT_WIDTH=%d", lut));
 			if (!noalumacc)
-				run("alumacc");
+				run("alumacc", "  (unless -noalumacc)");
 			if (!noshare)
-				run("share");
+				run("share", "    (unless -noshare)");
 			run("opt");
 			if (!nofsm)
-				run("fsm" + fsm_opts);
+				run("fsm" + fsm_opts, "      (unless -nofsm)");
 			run("opt -fast");
 			run("memory -nomap" + memory_opts);
 			run("opt_clean");
@@ -210,12 +236,33 @@ struct SynthPass : public ScriptPass
 			run("memory_map");
 			run("opt -full");
 			run("techmap");
+			if (help_mode)
+			{
+				run("techmap -map +/gate2lut.v", "(if -noabc and -lut)");
+				run("clean; opt_lut", "           (if -noabc and -lut)");
+			}
+			else if (noabc && lut)
+			{
+				run(stringf("techmap -map +/gate2lut.v -D LUT_WIDTH=%d", lut));
+				run("clean; opt_lut");
+			}
 			run("opt -fast");
 
 			if (!noabc) {
 		#ifdef YOSYS_ENABLE_ABC
-				run("abc -fast");
-				run("opt -fast");
+				if (help_mode)
+				{
+					run(abc + " -fast", "       (unless -noabc, unless -lut)");
+					run(abc + " -fast -lut k", "(unless -noabc, if -lut)");
+				}
+				else
+				{
+					if (lut)
+						run(stringf("%s -fast -lut %d", abc.c_str(), lut));
+					else
+						run(abc + " -fast");
+				}
+				run("opt -fast", "       (unless -noabc)");
 		#endif
 			}
 		}