Merge pull request #1186 from YosysHQ/eddie/abc9_ice40_fix

abc9/ice40: encapsulate SB_CARRY+SB_LUT4 into one box

passes/techmap/abc.cc

@@ -1172,7 +1172,7 @@ void abc_module(RTLIL::Design *design, RTLIL::Module *current_module, std::strin
 					continue;
 				}
 			}
-
+			else
 				cell_stats[RTLIL::unescape_id(c->type)]++;
 
 			if (c->type == "\\_const0_" || c->type == "\\_const1_") {

techlibs/ice40/abc_hx.box

@@ -3,15 +3,11 @@
 # NB: Inputs/Outputs must be ordered alphabetically
 #     (with exceptions for carry in/out)
 
-# Inputs: I0 I1 CI
+# Inputs: A B CI
-# Outputs: CO
+# Outputs: O CO
 #   (NB: carry chain input/output must be last
 #        input/output and have been moved there
 #        overriding the alphabetical ordering)
-SB_CARRY 1 1 3 1
+$__ICE40_FULL_ADDER 1 1 3 2
+400 379 316
 259 231 126
-
-# Inputs: I0 I1 I2 I3
-# Outputs: O
-SB_LUT4 2 1 4 1
-449 400 379 316

techlibs/ice40/abc_lp.box

@@ -3,15 +3,11 @@
 # NB: Inputs/Outputs must be ordered alphabetically
 #     (with exceptions for carry in/out)
 
-# Inputs: CI I0 I1
+# Inputs: A B CI
-# Outputs: CO
+# Outputs: O CO
 #   (NB: carry chain input/output must be last
 #        input/output and have been moved there
 #        overriding the alphabetical ordering)
-SB_CARRY 1 1 3 1
+$__ICE40_FULL_ADDER 1 1 3 2
+589 558 465
 675 609 186 
-
-# Inputs: I0 I1 I2 I3
-# Outputs: O
-SB_LUT4 2 1 4 1
-661 589 558 465

techlibs/ice40/abc_u.box

@@ -3,15 +3,11 @@
 # NB: Inputs/Outputs must be ordered alphabetically
 #     (with exceptions for carry in/out)
 
-# Inputs: I0 I1 CI
+# Inputs: A B CI
-# Outputs: CO
+# Outputs: O CO
 #   (NB: carry chain input/output must be last
 #        input/output and have been moved there
 #        overriding the alphabetical ordering)
-SB_CARRY 1 1 3 1
+$__ICE40_FULL_ADDER 1 1 3 2
+1231 1205 874
 675  609  278
-
-# Inputs: I0 I1 I2 I3
-# Outputs: O
-SB_LUT4 2 1 4 1
-1285 1231 1205 874

techlibs/ice40/arith_map.v

@@ -44,6 +44,15 @@ module _80_ice40_alu (A, B, CI, BI, X, Y, CO);
 
 	genvar i;
 	generate for (i = 0; i < Y_WIDTH; i = i + 1) begin:slice
+`ifdef _ABC
+		\$__ICE40_FULL_ADDER carry (
+			.A(AA[i]),
+			.B(BB[i]),
+			.CI(C[i]),
+			.CO(CO[i]),
+			.O(Y[i])
+		);
+`else
 		SB_CARRY carry (
 			.I0(AA[i]),
 			.I1(BB[i]),
@@ -63,6 +72,7 @@ module _80_ice40_alu (A, B, CI, BI, X, Y, CO);
 			.I3(C[i]),
 			.O(Y[i])
 		);
+`endif
 	end endgenerate
 
 	assign X = AA ^ BB;

techlibs/ice40/cells_map.v

@@ -61,3 +61,27 @@ module \$lut (A, Y);
   endgenerate
 endmodule
 `endif
+
+`ifdef _ABC
+module \$__ICE40_FULL_ADDER (output CO, O, input A, B, CI);
+  SB_CARRY carry (
+    .I0(A),
+    .I1(B),
+    .CI(CI),
+    .CO(CO)
+  );
+  SB_LUT4 #(
+    //         I0: 1010 1010 1010 1010
+    //         I1: 1100 1100 1100 1100
+    //         I2: 1111 0000 1111 0000
+    //         I3: 1111 1111 0000 0000
+    .LUT_INIT(16'b 0110_1001_1001_0110)
+  ) adder (
+    .I0(1'b0),
+    .I1(A),
+    .I2(B),
+    .I3(CI),
+    .O(O)
+  );
+endmodule
+`endif

techlibs/ice40/cells_sim.v

@@ -127,7 +127,7 @@ endmodule
 
 // SiliconBlue Logic Cells
 
-(* abc_box_id = 2, lib_whitebox *)
+(* lib_whitebox *)
 module SB_LUT4 (output O, input I0, I1, I2, I3);
 	parameter [15:0] LUT_INIT = 0;
 	wire [7:0] s3 = I3 ? LUT_INIT[15:8] : LUT_INIT[7:0];
@@ -136,11 +136,34 @@ module SB_LUT4 (output O, input I0, I1, I2, I3);
 	assign O = I0 ? s1[1] : s1[0];
 endmodule
 
-(* abc_box_id = 1, abc_carry="CI,CO", lib_whitebox *)
+(* lib_whitebox *)
 module SB_CARRY (output CO, input I0, I1, CI);
 	assign CO = (I0 && I1) || ((I0 || I1) && CI);
 endmodule
 
+(* abc_box_id = 1, abc_carry="CI,CO", lib_whitebox *)
+module \$__ICE40_FULL_ADDER (output CO, O, input A, B, CI);
+	SB_CARRY carry (
+		.I0(A),
+		.I1(B),
+		.CI(CI),
+		.CO(CO)
+	);
+	SB_LUT4 #(
+		//         I0: 1010 1010 1010 1010
+		//         I1: 1100 1100 1100 1100
+		//         I2: 1111 0000 1111 0000
+		//         I3: 1111 1111 0000 0000
+		.LUT_INIT(16'b 0110_1001_1001_0110)
+	) adder (
+		.I0(1'b0),
+		.I1(A),
+		.I2(B),
+		.I3(CI),
+		.O(O)
+	);
+endmodule
+
 // Positive Edge SiliconBlue FF Cells
 
 module SB_DFF (output `SB_DFF_REG, input C, D);

techlibs/ice40/ice40_opt.cc

@@ -83,6 +83,51 @@ static void run_ice40_opts(Module *module)
 			}
 			continue;
 		}
+
+		if (cell->type == "$__ICE40_FULL_ADDER")
+		{
+			SigSpec non_const_inputs, replacement_output;
+			int count_zeros = 0, count_ones = 0;
+
+			SigBit inbit[3] = {
+				cell->getPort("\\A"),
+				cell->getPort("\\B"),
+				cell->getPort("\\CI")
+			};
+			for (int i = 0; i < 3; i++)
+				if (inbit[i].wire == nullptr) {
+					if (inbit[i] == State::S1)
+						count_ones++;
+					else
+						count_zeros++;
+				} else
+					non_const_inputs.append(inbit[i]);
+
+			if (count_zeros >= 2)
+				replacement_output = State::S0;
+			else if (count_ones >= 2)
+				replacement_output = State::S1;
+			else if (GetSize(non_const_inputs) == 1)
+				replacement_output = non_const_inputs;
+
+			if (GetSize(replacement_output)) {
+				optimized_co.insert(sigmap(cell->getPort("\\CO")[0]));
+				module->connect(cell->getPort("\\CO")[0], replacement_output);
+				module->design->scratchpad_set_bool("opt.did_something", true);
+				log("Optimized $__ICE40_FULL_ADDER cell back to logic (without SB_CARRY) %s.%s: CO=%s\n",
+						log_id(module), log_id(cell), log_signal(replacement_output));
+				cell->type = "$lut";
+				cell->setPort("\\A", { RTLIL::S0, inbit[0], inbit[1], inbit[2] });
+				cell->setPort("\\Y", cell->getPort("\\O"));
+				cell->unsetPort("\\B");
+				cell->unsetPort("\\CI");
+				cell->unsetPort("\\CO");
+				cell->unsetPort("\\O");
+				cell->setParam("\\LUT", RTLIL::Const::from_string("0110100110010110"));
+				cell->setParam("\\WIDTH", 4);
+			}
+			continue;
+		}
 	}
 
 	for (auto cell : sb_lut_cells)

techlibs/ice40/synth_ice40.cc

@@ -238,7 +238,7 @@ struct SynthIce40Pass : public ScriptPass
 	{
 		if (check_label("begin"))
 		{
-			run("read_verilog -lib -D_ABC +/ice40/cells_sim.v");
+			run("read_verilog -icells -lib -D_ABC +/ice40/cells_sim.v");
 			run(stringf("hierarchy -check %s", help_mode ? "-top <top>" : top_opt.c_str()));
 			run("proc");
 		}
@@ -294,7 +294,7 @@ struct SynthIce40Pass : public ScriptPass
 			if (nocarry)
 				run("techmap");
 			else
-				run("techmap -map +/techmap.v -map +/ice40/arith_map.v");
+				run("techmap -map +/techmap.v -map +/ice40/arith_map.v" + std::string(abc == "abc9" ? " -D _ABC" : ""));
 			if (retime || help_mode)
 				run(abc + " -dff", "(only if -retime)");
 			run("ice40_opt");
@@ -338,6 +338,7 @@ struct SynthIce40Pass : public ScriptPass
 					else
 						wire_delay = 250;
 					run(abc + stringf(" -W %d -lut +/ice40/abc_%s.lut -box +/ice40/abc_%s.box", wire_delay, device_opt.c_str(), device_opt.c_str()), "(skip if -noabc)");
+					run("techmap -D NO_LUT -D _ABC -map +/ice40/cells_map.v");
 				}
 				else
 					run(abc + " -dress -lut 4", "(skip if -noabc)");