Merge pull request #4779 from YosysHQ/emil/han-carlson-adder

Add a Han-Carlson option for `$lcu` mapping

Author: widlarizer

techlibs/common/Makefile.inc

@@ -36,3 +36,4 @@ $(eval $(call add_share_file,share,techlibs/common/abc9_unmap.v))
 $(eval $(call add_share_file,share,techlibs/common/cmp2lcu.v))
 $(eval $(call add_share_file,share,techlibs/common/cmp2softlogic.v))
 $(eval $(call add_share_file,share/choices,techlibs/common/choices/kogge-stone.v))
+$(eval $(call add_share_file,share/choices,techlibs/common/choices/han-carlson.v))

techlibs/common/choices/han-carlson.v

@@ -0,0 +1,57 @@
+(* techmap_celltype = "$lcu" *)
+module _80_lcu_han_carlson (P, G, CI, CO);
+	parameter WIDTH = 2;
+
+	(* force_downto *)
+	input [WIDTH-1:0] P, G;
+	input CI;
+
+	(* force_downto *)
+	output [WIDTH-1:0] CO;
+
+	integer i, j;
+	(* force_downto *)
+	reg [WIDTH-1:0] p, g;
+
+	always @* begin
+		i = 0;
+		p = P;
+		g = G;
+
+		// in almost all cases CI will be constant zero
+		g[0] = g[0] | (p[0] & CI);
+		if (i < $clog2(WIDTH)) begin
+
+			// First layer: BK
+			for (j = WIDTH - 1; j >= 0; j = j - 1) begin
+				if (j % 2 == 1) begin
+					g[j] = g[j] | p[j] & g[j - 1];
+					p[j] = p[j] & p[j - 1];
+				end
+			end
+
+			// Inner (log(WIDTH) - 1) layers: KS
+			for (i = 1; i < $clog2(WIDTH); i = i + 1) begin
+				for (j = WIDTH - 1; j >= 2**i; j = j - 1) begin
+					if (j % 2 == 1) begin
+						g[j] = g[j] | p[j] & g[j - 2**i];
+						p[j] = p[j] & p[j - 2**i];
+					end
+				end
+			end
+
+			// Last layer: BK
+			if (i < ($clog2(WIDTH) + 1)) begin
+				for (j = WIDTH - 1; j >= 0; j = j - 1) begin
+					if ((j % 2 == 0) && (j > 0)) begin
+						g[j] = g[j] | p[j] & g[j - 1];
+						p[j] = p[j] & p[j - 1];
+					end
+				end
+			end
+
+		end
+	end
+
+	assign CO = g;
+endmodule

tests/gen-tests-makefile.sh

@@ -20,6 +20,13 @@ generate_ys_test() {
 	generate_target "$ys_file" "\"$YOSYS_BASEDIR/yosys\" -ql ${ys_file%.*}.log $yosys_args_ $ys_file"
 }
 
+# $ generate_tcl_test tcl_file [yosys_args]
+generate_tcl_test() {
+	tcl_file=$1
+	yosys_args_=${2:-}
+	generate_target "$tcl_file" "\"$YOSYS_BASEDIR/yosys\" -ql ${tcl_file%.*}.log $yosys_args_ $tcl_file"
+}
+
 # $ generate_bash_test bash_file
 generate_bash_test() {
 	bash_file=$1
@@ -29,6 +36,7 @@ generate_bash_test() {
 # $ generate_tests [-y|--yosys-scripts] [-s|--prove-sv] [-b|--bash] [-a|--yosys-args yosys_args]
 generate_tests() {
 	do_ys=false
+	do_tcl=false
 	do_sv=false
 	do_sh=false
 	yosys_args=""
@@ -40,6 +48,10 @@ generate_tests() {
 				do_ys=true
 				shift
 				;;
+			-t|--tcl-scripts)
+				do_tcl=true
+				shift
+				;;
 			-s|--prove-sv)
 				do_sv=true
 				shift
@@ -59,7 +71,7 @@ generate_tests() {
 		esac
 	done
 
-	if [[ ! ( $do_ys = true || $do_sv = true || $do_sh = true ) ]]; then
+	if [[ ! ( $do_ys = true || $do_tcl = true || $do_sv = true || $do_sh = true ) ]]; then
 		echo >&2 "Error: No file types selected"
 		exit 1
 	fi
@@ -72,6 +84,11 @@ generate_tests() {
 			generate_ys_test "$x" "$yosys_args"
 		done
 	fi;
+	if [[ $do_tcl = true ]]; then
+		for x in *.tcl; do
+			generate_tcl_test "$x" "$yosys_args"
+		done
+	fi;
 	if [[ $do_sv = true ]]; then
 		for x in *.sv; do
 			if [ ! -f "${x%.sv}.ys"  ]; then

tests/techmap/han-carlson.tcl

@@ -0,0 +1,15 @@
+yosys -import
+
+read_verilog +/choices/han-carlson.v
+read_verilog -icells lcu_refined.v
+design -save init
+
+for {set i 1} {$i <= 16} {incr i} {
+    design -load init
+    chparam -set WIDTH $i
+    yosys proc
+    opt_clean
+    equiv_make lcu _80_lcu_han_carlson equiv
+    equiv_simple equiv
+    equiv_status -assert equiv
+}

tests/techmap/kogge-stone.tcl

@@ -0,0 +1,15 @@
+yosys -import
+
+read_verilog +/choices/kogge-stone.v
+read_verilog -icells lcu_refined.v
+design -save init
+
+for {set i 1} {$i <= 16} {incr i} {
+    design -load init
+    chparam -set WIDTH $i
+    yosys proc
+    opt_clean
+    equiv_make lcu _80_lcu_kogge_stone equiv
+    equiv_simple equiv
+    equiv_status -assert equiv
+}

tests/techmap/kogge-stone.ys

@@ -0,0 +1,13 @@
+module lcu (P, G, CI, CO);
+	parameter WIDTH = 2;
+
+	input [WIDTH-1:0] P, G;
+	input CI;
+
+	output [WIDTH-1:0] CO;
+
+	reg [WIDTH-1:0] p, g;
+
+	\$lcu #(.WIDTH(WIDTH)) impl (.P(P), .G(G), .CI(CI), .CO(CO));
+
+endmodule

tests/techmap/lcu_refined.v

@@ -1,4 +1,4 @@
 #!/usr/bin/env bash
 set -eu
 source ../gen-tests-makefile.sh
-run_tests --yosys-scripts --bash --yosys-args "-e 'select out of bounds'"
+run_tests --yosys-scripts --tcl-scripts --bash --yosys-args "-e 'select out of bounds'"