1 files changed, 109 insertions, 0 deletions
diff --git a/passes/techmap/recover_reduce_core.cpp b/passes/techmap/recover_reduce_core.cpp
new file mode 100644
index 000000000..e6b9ec879
--- /dev/null
+++ b/passes/techmap/recover_reduce_core.cpp
@@ -0,0 +1,109 @@
+/*
+ *  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