Added "zinit" pass

1 files changed, 151 insertions, 0 deletions

diff --git a/passes/techmap/zinit.cc b/passes/techmap/zinit.cc
new file mode 100644
index 000000000..a577e1235
--- /dev/null
+++ b/passes/techmap/zinit.cc
@@ -0,0 +1,151 @@
+/*
+ *  yosys -- Yosys Open SYnthesis Suite
+ *
+ *  Copyright (C) 2012  Clifford Wolf <clifford@clifford.at>
+ *
+ *  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
+
+struct ZinitPass : public Pass {
+	ZinitPass() : Pass("zinit", "add inverters so all FF are zero-initialized") { }
+	virtual void help()
+	{
+		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
+		log("\n");
+		log("    zinit [options] [selection]\n");
+		log("\n");
+		log("Add inverters as needed to make all FFs zero-initialized.\n");
+		log("\n");
+		log("    -all\n");
+		log("        also add zero initialization to uninitialized FFs\n");
+		log("\n");
+	}
+	virtual void execute(std::vector<std::string> args, RTLIL::Design *design)
+	{
+		bool all_mode = false;
+
+		log_header(design, "Executing ZINIT pass (make all FFs zero-initialized).\n");
+
+		size_t argidx;
+		for (argidx = 1; argidx < args.size(); argidx++)
+		{
+			if (args[argidx] == "-singleton") {
+				all_mode = true;
+				continue;
+			}
+			break;
+		}
+		extra_args(args, argidx, design);
+
+		for (auto module : design->selected_modules())
+		{
+			SigMap sigmap(module);
+			dict<SigBit, State> initbits;
+			pool<SigBit> donebits;
+
+			for (auto wire : module->selected_wires())
+			{
+				if (wire->attributes.count("\\init") == 0)
+					continue;
+
+				SigSpec wirebits = sigmap(wire);
+				Const initval = wire->attributes.at("\\init");
+				wire->attributes.erase("\\init");
+
+				for (int i = 0; i < GetSize(wirebits) && i < GetSize(initval); i++)
+				{
+					SigBit bit = wirebits[i];
+					State val = initval[i];
+
+					if (val != State::S0 && val != State::S1 && bit.wire != nullptr)
+						continue;
+
+					if (initbits.count(bit)) {
+						if (initbits.at(bit) != val)
+							log_error("Conflicting init values for signal %s (%s = %s != %s).\n",
+									log_signal(bit), log_signal(SigBit(wire, i)),
+									log_signal(val), log_signal(initbits.at(bit)));
+						continue;
+					}
+
+					initbits[bit] = val;
+				}
+			}
+
+			pool<IdString> dff_types = {
+				"$ff", "$dff", "$dffe", "$dffsr", "$adff",
+				"$_FF_", "$_DFFE_NN_", "$_DFFE_NP_", "$_DFFE_PN_", "$_DFFE_PP_",
+				"$_DFFSR_NNN_", "$_DFFSR_NNP_", "$_DFFSR_NPN_", "$_DFFSR_NPP_",
+				"$_DFFSR_PNN_", "$_DFFSR_PNP_", "$_DFFSR_PPN_", "$_DFFSR_PPP_",
+				"$_DFF_N_", "$_DFF_NN0_", "$_DFF_NN1_", "$_DFF_NP0_", "$_DFF_NP1_",
+				"$_DFF_P_", "$_DFF_PN0_", "$_DFF_PN1_", "$_DFF_PP0_", "$_DFF_PP1_"
+			};
+
+			for (auto cell : module->selected_cells())
+			{
+				if (!dff_types.count(cell->type))
+					continue;
+
+				SigSpec sig_d = sigmap(cell->getPort("\\D"));
+				SigSpec sig_q = sigmap(cell->getPort("\\Q"));
+
+				if (GetSize(sig_d) < 1 || GetSize(sig_q) < 1)
+					continue;
+
+				Const initval;
+
+				for (int i = 0; i < GetSize(sig_q); i++) {
+					if (initbits.count(sig_q[i])) {
+						initval.bits.push_back(initbits.at(sig_q[i]));
+						donebits.insert(sig_q[i]);
+					} else
+						initval.bits.push_back(all_mode ? State::S0 : State::Sx);
+				}
+
+				Wire *initwire = module->addWire(NEW_ID, GetSize(initval));
+				initwire->attributes["\\init"] = initval;
+
+				for (int i = 0; i < GetSize(initwire); i++)
+					if (initval.bits.at(i) == State::S1)
+					{
+						sig_d[i] = module->NotGate(NEW_ID, sig_d[i]);
+						module->addNotGate(NEW_ID, SigSpec(initwire, i), sig_q[i]);
+						initwire->attributes["\\init"].bits.at(i) = State::S0;
+					}
+					else
+					{
+						module->connect(sig_q[i], SigSpec(initwire, i));
+					}
+
+				log("FF init value for cell %s (%s): %s = %s\n", log_id(cell), log_id(cell->type),
+						log_signal(sig_q), log_signal(initval));
+
+				cell->setPort("\\D", sig_d);
+				cell->setPort("\\Q", initwire);
+			}
+
+			for (auto &it : initbits)
+				if (donebits.count(it.first) == 0)
+					log_error("Failed to handle init bit %s = %s.\n", log_signal(it.first), log_signal(it.second));
+		}
+	}
+} ZinitPass;
+
+PRIVATE_NAMESPACE_END