Initial carry chain handling pass

techlibs/nanoxplore/Makefile.inc

@@ -1,5 +1,6 @@
 
 OBJS += techlibs/nanoxplore/synth_nanoxplore.o
+OBJS += techlibs/nanoxplore/nx_carry.o
 
 # Techmap
 $(eval $(call add_share_file,share/nanoxplore,techlibs/nanoxplore/arith_map.v))

techlibs/nanoxplore/arith_map.v

@@ -1,4 +1,21 @@
-`default_nettype none
+/*
+ *  yosys -- Yosys Open SYnthesis Suite
+ *
+ *  Copyright (C) 2024  Miodrag Milanovic <[email protected]>
+ *
+ *  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.
+ *
+ */
 
 (* techmap_celltype = "$alu" *)
 module _80_nx_cy_alu (A, B, CI, BI, X, Y, CO);
@@ -26,46 +43,32 @@ module _80_nx_cy_alu (A, B, CI, BI, X, Y, CO);
 	\$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));
 
-	function integer round_up4;
-		input integer N;
-		begin
-			round_up4 = ((N + 3) / 4) * 4;
-		end
-	endfunction
-
-	localparam Y_WIDTH4 = round_up4(Y_WIDTH);
-
-	(* force_downto *)
-	wire [Y_WIDTH4-1:0] AA = A_buf;
-	(* force_downto *)
-	wire [Y_WIDTH4-1:0] BB = BI ? ~B_buf : B_buf;
-	(* force_downto *)
-	wire [Y_WIDTH4-1:0] BX = B_buf;
 	(* force_downto *)
-	wire [Y_WIDTH4:0] C = {CO, CI};
+	wire [Y_WIDTH-1:0] AA = A_buf;
 	(* force_downto *)
-	wire [Y_WIDTH4-1:0] FCO, Y1;
+	wire [Y_WIDTH-1:0] BB = BI ? ~B_buf : B_buf;
 
 	genvar i;
-	generate for (i = 0; i < Y_WIDTH4; i = i + 4) begin:slice
-        NX_CY cy_i (
-            .CI(C[i]),
-            .A1(AA[i]), .A2(AA[i+1]), .A3(AA[i+2]), .A4(AA[i+3]),
-            .B1(BB[i]), .B2(BB[i+1]), .B3(BB[i+2]), .B4(BB[i+3]),
-            .S1(Y1[i]), .S2(Y1[i+1]), .S3(Y1[i+2]), .S4(Y1[i+3]),
-            .CO(FCO[i])
-        );
+	generate for (i = 0; i < Y_WIDTH; i = i + 1) begin: slice
+		NX_CY_1BIT #(.first(i==0))
+			alu_i (
+			.CI(i==0 ? CI : CO[i-1]),
+			.A(AA[i]),
+			.B(BB[i]),
+			.S(Y[i]),
+			.CO(CO[i])
+		);
 
-		assign CO[i] = (AA[i] && BB[i]) || (C[i] && (AA[i] || BB[i]));
-        if (i+1 < Y_WIDTH)
-		    assign CO[i+1] = (AA[i+1] && BB[i+1]) || (C[i+1] && (AA[i+1] || BB[i+1]));
-		if (i+2 < Y_WIDTH)
-            assign CO[i+2] = (AA[i+2] && BB[i+2]) || (C[i+2] && (AA[i+2] || BB[i+2]));
-        if (i+3 < Y_WIDTH)
-            assign CO[i+3] = FCO[i];
+	end: slice
+	endgenerate
 
-	end endgenerate
+	NX_CY_1BIT alu_cout(
+		.CI(CO[Y_WIDTH-1]),
+		.A(1'b0),
+		.B(1'b0),
+		.S(CO[Y_WIDTH-1])
+	);
 
-	assign X = AA ^ BB;
-    assign Y = Y1[Y_WIDTH-1:0];
+   /* End implementation */
+   assign X = AA ^ BB;
 endmodule

techlibs/nanoxplore/cells_sim.v

@@ -184,4 +184,16 @@ module NX_IOB_O(I, C, T, IO);
 	assign IO = C ? I : 1'bz;
 endmodule
 
-
+(* abc9_box, lib_whitebox *)
+module NX_CY_1BIT(CI, A, B, S, CO);
+    (* abc9_carry *)
+    input CI;
+    input A;
+    input B;
+    output S;
+    (* abc9_carry *)
+    output CO;
+    parameter first = 1'b0;
+
+    assign {CO, S} = A + B + CI;
+endmodule

techlibs/nanoxplore/nx_carry.cc

@@ -0,0 +1,151 @@
+/*
+ *  yosys -- Yosys Open SYnthesis Suite
+ *
+ *  Copyright (C) 2024  Miodrag Milanovic <[email protected]>
+ *
+ *  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.
+ *
+ */
+
+#include "kernel/yosys.h"
+#include "kernel/sigtools.h"
+
+USING_YOSYS_NAMESPACE
+PRIVATE_NAMESPACE_BEGIN
+
+static void nx_carry_chain(Module *module)
+{
+	SigMap sigmap(module);
+
+	dict<Cell*,SigBit> carry_ci_propagate;
+	for (auto cell : module->selected_cells())
+	{
+		if (cell->type == ID(NX_CY_1BIT)) {
+			// Only first can have CI generated that is not constant
+			if (cell->getParam(ID(first)).as_int() == 0) continue;
+			if (!cell->getPort(ID(CI)).is_wire()) continue;
+			carry_ci_propagate[cell] = cell->getPort(ID(CI)).as_bit();
+		}
+	}
+
+	for (auto cy : carry_ci_propagate)
+	{
+		Cell *cell = cy.first;
+		cell->setParam(ID(first), Const(0, 1));
+
+		SigBit new_co = module->addWire(NEW_ID);
+		Cell *c = module->addCell(NEW_ID, ID(NX_CY_1BIT));
+		c->setParam(ID(first), Const(1));
+		c->setPort(ID(CI), State::S0);
+		c->setPort(ID(A), cy.second);
+		c->setPort(ID(B), State::S0);
+		c->setPort(ID(CO), new_co);
+		cell->setPort(ID(CI), new_co);
+
+		log("Adding cell %s to propaget CI signal.\n", log_id(cell));
+	}
+	carry_ci_propagate.clear();
+
+	dict<SigBit,Cell*> carry;
+	for (auto cell : module->selected_cells())
+	{
+		if (cell->type == ID(NX_CY_1BIT)) {
+			if (cell->getParam(ID(first)).as_int() == 1) continue;
+			if (!cell->hasPort(ID(CI)))
+				log_error("Not able to find connected carry.\n");
+			SigBit ci = sigmap(cell->getPort(ID(CI)).as_bit());
+			carry[ci] = cell;
+		}
+	}
+
+	dict<Cell*,vector<Cell*>> carry_chains;
+	log("Detecting carry chains\n");
+	for (auto cell : module->selected_cells())
+	{
+		if (cell->type == ID(NX_CY_1BIT)) {
+			if (cell->getParam(ID(first)).as_int() == 0) continue;
+
+			vector<Cell*> chain;
+			SigBit co = sigmap(cell->getPort(ID(CO)).as_bit());
+			Cell *current = cell;
+			chain.push_back(current);
+			while (co.is_wire())
+			{
+				if (carry.count(co)==0)
+					break;
+					//log_error("Not able to find connected carry.\n");
+				current = carry[co];
+				chain.push_back(current);
+				if (!current->hasPort(ID(CO))) break;
+				co = sigmap(current->getPort(ID(CO)).as_bit());
+			}
+			carry_chains[cell] = chain;
+		}
+	}
+
+	log("Creating NX_CY cells.\n");
+	for(auto& c : carry_chains) {
+		Cell *cell = nullptr;
+		int j = 0;
+		IdString names_A[] = { ID(A1), ID(A2), ID(A3), ID(A4) };
+		IdString names_B[] = { ID(B1), ID(B2), ID(B3), ID(B4) };
+		IdString names_S[] = { ID(S1), ID(S2), ID(S3), ID(S4) };
+		for (size_t i=0 ; i<c.second.size(); i++) {
+			if (j==0) {
+				cell = module->addCell(NEW_ID, ID(NX_CY));
+				cell->setPort(ID(CI), c.second.at(i)->getPort(ID(CI)));
+			}
+			if (j==3)
+				cell->setPort(ID(CO), c.second.at(i)->getPort(ID(CO)));
+
+
+			cell->setPort(names_A[j], (c.second.at(i)->hasPort(ID(A))) ? c.second.at(i)->getPort(ID(A)) : State::S0);
+			cell->setPort(names_B[j], (c.second.at(i)->hasPort(ID(B))) ? c.second.at(i)->getPort(ID(B)) : State::S0);
+
+			if (c.second.at(i)->hasPort(ID(S))) 
+				cell->setPort(names_S[j], c.second.at(i)->getPort(ID(S)));
+
+			j = (j + 1) % 4;
+			module->remove(c.second.at(i));
+		}
+	}
+}
+
+struct NXCarryPass : public Pass {
+	NXCarryPass() : Pass("nx_carry", "NanoXplore: create carry cells") { }
+	void help() override
+	{
+		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
+		log("\n");
+		log("    nx_carry [options] [selection]\n");
+		log("\n");
+		log("Fixes carry chain if needed, break it on 24 elements and group by 4 into NX_CY.\n");
+		log("\n");
+	}
+	void execute(std::vector<std::string> args, RTLIL::Design *design) override
+	{
+		log_header(design, "Executing NX_CARRY pass.\n");
+
+		size_t argidx;
+		for (argidx = 1; argidx < args.size(); argidx++)
+		{
+			break;
+		}
+		extra_args(args, argidx, design);
+
+		for (auto module : design->selected_modules())
+			nx_carry_chain(module);
+	}
+} NXCarryPass;
+
+PRIVATE_NAMESPACE_END

techlibs/nanoxplore/synth_nanoxplore.cc

@@ -279,8 +279,10 @@ struct SynthNanoXplorePass : public ScriptPass
 		{
 			if (nocy)
 				run("techmap");
-			else
+			else {
 				run("techmap -map +/techmap.v -map +/nanoxplore/arith_map.v");
+				run("nx_carry");
+			}
 			if (help_mode || iopad) {
 				run("iopadmap -bits -outpad $__BEYOND_OBUF I:PAD -inpad $__BEYOND_IBUF O:PAD A:top", "(only if '-iopad')");
 				run("techmap -map +/nanoxplore/io_map.v");