From 5170b861084823581382969220c7f1ea85e58656 Mon Sep 17 00:00:00 2001
From: Clifford Wolf <clifford@clifford.at>
Date: Sun, 8 Feb 2015 11:59:38 +0100
Subject: [PATCH] Added equiv_add

---
 passes/equiv/Makefile.inc |  1 +
 passes/equiv/equiv_add.cc | 89 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 90 insertions(+)
 create mode 100644 passes/equiv/equiv_add.cc

diff --git a/passes/equiv/Makefile.inc b/passes/equiv/Makefile.inc
index 06b00ef34..548eaca3b 100644
--- a/passes/equiv/Makefile.inc
+++ b/passes/equiv/Makefile.inc
@@ -3,6 +3,7 @@ OBJS += passes/equiv/equiv_make.o
 OBJS += passes/equiv/equiv_miter.o
 OBJS += passes/equiv/equiv_simple.o
 OBJS += passes/equiv/equiv_status.o
+OBJS += passes/equiv/equiv_add.o
 OBJS += passes/equiv/equiv_remove.o
 OBJS += passes/equiv/equiv_induct.o
 
diff --git a/passes/equiv/equiv_add.cc b/passes/equiv/equiv_add.cc
new file mode 100644
index 000000000..a6e2f01b4
--- /dev/null
+++ b/passes/equiv/equiv_add.cc
@@ -0,0 +1,89 @@
+/*
+ *  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 EquivAddPass : public Pass {
+	EquivAddPass() : Pass("equiv_add", "add a $equiv cell") { }
+	virtual void help()
+	{
+		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
+		log("\n");
+		log("    equiv_add gold_sig gate_sig\n");
+		log("\n");
+		log("This command adds an $equiv cell for the specified signals.\n");
+		log("\n");
+	}
+	virtual void execute(std::vector<std::string> args, Design *design)
+	{
+		if (GetSize(args) != 3)
+			 cmd_error(args, GetSize(args)-1, "Invalid number of arguments.");
+
+		if (design->selected_active_module.empty())
+			log_cmd_error("This command must be executed in module context!\n");
+
+		Module *module = design->module(design->selected_active_module);
+		log_assert(module != nullptr);
+
+		SigSpec gold_signal, gate_signal;
+
+		if (!SigSpec::parse(gate_signal, module, args[2]))
+			log_cmd_error("Error in gate signal: %s\n", args[2].c_str());
+
+		if (!SigSpec::parse_rhs(gate_signal, gold_signal, module, args[1]))
+			log_cmd_error("Error in gold signal: %s\n", args[1].c_str());
+
+		log_assert(GetSize(gold_signal) == GetSize(gate_signal));
+		SigSpec equiv_signal = module->addWire(NEW_ID, GetSize(gold_signal));
+
+		SigMap sigmap(module);
+		sigmap.apply(gold_signal);
+		sigmap.apply(gate_signal);
+
+		dict<SigBit, SigBit> to_equiv_bits;
+		pool<Cell*> added_equiv_cells;
+
+		for (int i = 0; i < GetSize(gold_signal); i++) {
+			Cell *equiv_cell = module->addEquiv(NEW_ID, gold_signal[i], gate_signal[i], equiv_signal[i]);
+			equiv_cell->set_bool_attribute("\\keep");
+			to_equiv_bits[gold_signal[i]] = equiv_signal[i];
+			to_equiv_bits[gate_signal[i]] = equiv_signal[i];
+			added_equiv_cells.insert(equiv_cell);
+		}
+
+		for (auto cell : module->cells())
+		for (auto conn : cell->connections())
+			if (!added_equiv_cells.count(cell) && cell->input(conn.first)) {
+				SigSpec new_sig;
+				for (auto bit : conn.second)
+					if (to_equiv_bits.count(sigmap(bit)))
+						new_sig.append(to_equiv_bits.at(sigmap(bit)));
+					else
+						 new_sig.append(bit);
+				if (conn.second != new_sig)
+					cell->setPort(conn.first, new_sig);
+			}
+	}
+} EquivAddPass;
+
+PRIVATE_NAMESPACE_END
-- 
2.30.2