abc9: add flop boxes to basic $_DFF_P_ and $_DFF_N_ too

passes/techmap/abc9.cc

@@ -314,23 +314,24 @@ struct Abc9Pass : public ScriptPass
 						}
 					}
 					run("design -stash $abc9_map");
+				}
 				run("design -load $abc9");
 				run("design -delete $abc9");
 				run("select -unset $abc9_flops");
-					run("techmap -wb -map %$abc9_map"); // techmap user design into submod + $_DFF_[NP]_
+				if (did_something) { // techmap user design into submod + $_DFF_[NP]_
+					run("techmap -wb -max_iter 1 -map %$abc9_map -map +/abc9_map.v");
 					run("design -delete $abc9_map");
 					run("setattr -mod -set whitebox 1 -set abc9_flop 1 -set abc9_box 1 *_$abc9_flop");
 					run("abc9_ops -prep_dff_unmap"); // implement $abc9_unmap design
 				}
-				else {
+				else
-					run("design -load $abc9");
+					run("techmap -wb -max_iter 1 -map +/abc9_map.v");
-					run("design -delete $abc9");
+
-					run("select -unset $abc9_flops");
-				}
 			}
 		}
 
 		if (check_label("pre")) {
+			run("read_verilog -icells -lib -specify +/abc9_model.v");
 			run("scc -set_attr abc9_scc_id {}");
 			if (help_mode)
 				run("abc9_ops -mark_scc -prep_delays -prep_xaiger [-dff]", "(option for -dff)");

passes/techmap/abc9_ops.cc

@@ -128,7 +128,7 @@ void prep_dff_hier(RTLIL::Design *design)
 
 	Design *unmap_design = new Design;
 
-	for (auto module : design->selected_modules())
+	for (auto module : design->modules())
 		for (auto cell : module->cells()) {
 			auto inst_module = design->module(cell->type);
 			if (inst_module && inst_module->attributes.count(ID::abc9_flop)) {
@@ -219,17 +219,23 @@ void prep_dff_map(RTLIL::Design *design)
 
 		D = dff_cell->getPort(ID::D);
 
-		// Add a dummy enable mux feeding DFF.D to ensure that:
-		//   (i) a driving cell exists, so that 'submod' will have
-		//       an output port
-		//   (ii) DFF.Q will exist in this submodule
 		{
-			auto c = module->addCell(NEW_ID, ID($_MUX_));
+			// Add dummy buffers for all module inputs/outputs
+			//   to ensure that these ports exists in the flop box
+			//   created by later submod pass
+			for (auto port_name : module->ports) {
+				auto port = module->wire(port_name);
+				log_assert(GetSize(port) == 1);
+				auto c = module->addBufGate(NEW_ID, port, module->addWire(NEW_ID));
+				// Need to set (* keep *) otherwise opt_clean
+				//   inside submod will blow it away
+				c->set_bool_attribute(ID::keep);
+			}
+			// Add an additional buffer that drives $_DFF_[NP]_.D
+			//   so that the flop box will have an output
 			auto w = module->addWire(NEW_ID);
-			c->setPort(ID::A, D);
+			auto c = module->addBufGate(NEW_ID, D, w);
-			c->setPort(ID::B, Q);
+			c->set_bool_attribute(ID::keep);
-			c->setPort(ID::S, State::S0);
-			c->setPort(ID::Y, w);
 			dff_cell->setPort(ID::D, w);
 			D = w;
 		}

techlibs/common/Makefile.inc

@@ -30,4 +30,6 @@ $(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/mul2dsp.v))
 $(eval $(call add_share_file,share,techlibs/common/abc9_model.v))
+$(eval $(call add_share_file,share,techlibs/common/abc9_map.v))
+$(eval $(call add_share_file,share,techlibs/common/abc9_unmap.v))
 $(eval $(call add_share_file,share,techlibs/common/cmp2lcu.v))

techlibs/common/abc9_map.v

@@ -0,0 +1,21 @@
+(* techmap_celltype = "$_DFF_N_ $_DFF_P_" *)
+module $_DFF_x_(input C, D, output Q);
+  parameter [0:0] _TECHMAP_WIREINIT_Q_ = 1'bx;
+  parameter _TECHMAP_CELLTYPE_ = "";
+  generate if (_TECHMAP_WIREINIT_Q_ === 1'b1)
+    wire _TECHMAP_FAIL_ = 1;
+  else if (_TECHMAP_CELLTYPE_ == "$_DFF_N_") begin
+    wire D_;
+    $__DFF_N__$abc9_flop #(.INIT(_TECHMAP_WIREINIT_Q_)) _TECHMAP_REPLACE_ (.C(C), .D(D), .Q(Q), .n1(D_));
+    $_DFF_N_ ff (.C(C), .D(D_), .Q(Q));
+  end
+  else if (_TECHMAP_CELLTYPE_ == "$_DFF_P_") begin
+    wire D_;
+    $__DFF_P__$abc9_flop #(.INIT(_TECHMAP_WIREINIT_Q_)) _TECHMAP_REPLACE_ (.C(C), .D(D), .Q(Q), .n1(D_));
+    $_DFF_P_ ff (.C(C), .D(D_), .Q(Q));
+  end
+  else if (_TECHMAP_CELLTYPE_ != "")
+    $error("Unrecognised _TECHMAP_CELLTYPE_");
+  endgenerate
+  wire _TECHMAP_REMOVEINIT_Q_ = 1;
+endmodule

techlibs/common/abc9_model.v

@@ -5,3 +5,23 @@ module \$__ABC9_DELAY (input I, output O);
     (I => O) = DELAY;
   endspecify
 endmodule
+
+(* abc9_flop, abc9_box, lib_whitebox *)
+module $__DFF_N__$abc9_flop(input C, D, Q, (* init=INIT *) output n1);
+  parameter [0:0] INIT = 1'bx;
+  assign n1 = D;
+  specify
+    $setup(D, posedge C, 0);
+    (posedge C => (n1:D)) = 0;
+  endspecify
+endmodule
+
+(* abc9_flop, abc9_box, lib_whitebox *)
+module $__DFF_P__$abc9_flop(input C, D, Q, (* init=INIT *) output n1);
+  parameter [0:0] INIT = 1'bx;
+  assign n1 = D;
+  specify
+    $setup(D, posedge C, 0);
+    (posedge C => (n1:D)) = 0;
+  endspecify
+endmodule

techlibs/common/abc9_unmap.v

@@ -0,0 +1,12 @@
+(* techmap_celltype = "$__DFF_N__$abc9_flop $__DFF_P__$abc9_flop" *)
+module $__DFF_x__$abc9_flop (input C, D, Q, (* init = INIT *) output n1);
+  parameter [0:0] INIT = 1'bx;
+  parameter _TECHMAP_CELLTYPE_ = "";
+  generate if (_TECHMAP_CELLTYPE_ == "$__DFF_N__$abc9_flop")
+    $_DFF_N_ _TECHMAP_REPLACE_ (.C(C), .D(D), .Q(Q));
+  else if (_TECHMAP_CELLTYPE_ == "$__DFF_P__$abc9_flop")
+    $_DFF_P_ _TECHMAP_REPLACE_ (.C(C), .D(D), .Q(Q));
+  else if (_TECHMAP_CELLTYPE_ != "")
+    $error("Unrecognised _TECHMAP_CELLTYPE_");
+  endgenerate
+endmodule

tests/various/abc9.ys

@@ -45,14 +45,16 @@ sat -seq 10 -verify -prove-asserts -show-ports miter
 design -reset
 read_verilog -icells <<EOT
 module abc9_test036(input clk, d, output q);
-(* keep *) reg w;
+(* keep, init=1'b0 *) wire w;
-$__ABC9_FF_ ff(.D(d), .Q(w));
+$_DFF_P_ ff(.C(clk), .D(d), .Q(w));
-wire \ff.clock = clk;
-wire \ff.init = 1'b0;
 assign q = w;
 endmodule
 EOT
-abc9 -lut 4 -dff
+equiv_opt abc9 -lut 4 -dff
+design -load postopt
+cd abc9_test036
+select -assert-count 1 t:$_DFF_P_
+select -assert-none t:* t:$_DFF_P_ %d
 
 
 design -reset