--- /dev/null
+/*
+ * yosys -- Yosys Open SYnthesis Suite
+ *
+ * Copyright (C) 2017 Robert Ou <rqou@robertou.com>
+ *
+ * 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 RecoverReduceCorePass : public Pass {
+ enum GateType {
+ And,
+ Or,
+ Xor
+ };
+
+ RecoverReduceCorePass() : Pass("recover_reduce_core", "converts gate chains into $reduce_*") { }
+ virtual void help()
+ {
+ // |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
+ log("\n");
+ log(" recover_reduce_core\n");
+ log("\n");
+ log("converts gate chains into $reduce_*\n");
+ log("\n");
+ log("This performs the core step of the recover_reduce command. This step recognizes\n");
+ log("chains of gates found by the previous steps and converts these chains into one\n");
+ log("logical cell.\n");
+ log("\n");
+ }
+ virtual void execute(std::vector<std::string> args, RTLIL::Design *design)
+ {
+ (void)args;
+
+ for (auto module : design->selected_modules())
+ {
+ SigMap sigmap(module);
+
+ // Index all of the nets in the module
+ dict<SigBit, Cell*> sig_to_driver;
+ dict<SigBit, pool<Cell*>> sig_to_sink;
+ for (auto cell : module->selected_cells())
+ {
+ for (auto &conn : cell->connections())
+ {
+ if (cell->output(conn.first))
+ for (auto bit : sigmap(conn.second))
+ sig_to_driver[bit] = cell;
+
+ if (cell->input(conn.first))
+ {
+ for (auto bit : sigmap(conn.second))
+ {
+ if (sig_to_sink.count(bit) == 0)
+ sig_to_sink[bit] = pool<Cell*>();
+ sig_to_sink[bit].insert(cell);
+ }
+ }
+ }
+ }
+
+ // Need to check if any wires connect to module ports
+ pool<SigBit> port_sigs;
+ for (auto wire : module->selected_wires())
+ if (wire->port_input || wire->port_output)
+ for (auto bit : sigmap(wire))
+ port_sigs.insert(bit);
+
+ // Actual logic starts here
+ pool<Cell*> consumed_cells;
+ for (auto cell : module->selected_cells())
+ {
+ if (consumed_cells.count(cell))
+ continue;
+
+ GateType gt;
+
+ if (cell->type == "$_AND_")
+ gt = GateType::And;
+ else if (cell->type == "$_OR_")
+ gt = GateType::Or;
+ else if (cell->type == "$_XOR_")
+ gt = GateType::Xor;
+ else
+ continue;
+
+ log("Working on cell %s...\n", cell->name.c_str());
+ }
+ }
+ }
+} RecoverReduceCorePass;
+
+PRIVATE_NAMESPACE_END