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+/*
+ * 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/log.h"
+#include "kernel/register.h"
+#include "kernel/sigtools.h"
+#include "kernel/consteval.h"
+#include "kernel/celltypes.h"
+#include "fsmdata.h"
+
+static RTLIL::Module *module;
+static SigMap assign_map;
+typedef std::pair<RTLIL::Cell*,std::string> sig2driver_entry_t;
+static SigSet<sig2driver_entry_t> sig2driver, sig2user;
+static std::set<RTLIL::Cell*> muxtree_cells;
+static SigPool sig_at_port;
+
+static bool check_state_mux_tree(RTLIL::SigSpec old_sig, RTLIL::SigSpec sig)
+{
+ if (sig_at_port.check_any(assign_map(sig)))
+ return false;
+
+ if (sig.is_fully_const() || old_sig == sig)
+ return true;
+
+ std::set<sig2driver_entry_t> cellport_list;
+ sig2driver.find(sig, cellport_list);
+ for (auto &cellport : cellport_list) {
+ if ((cellport.first->type != "$mux" && cellport.first->type != "$pmux" && cellport.first->type != "$safe_pmux") || cellport.second != "\\Y")
+ return false;
+ RTLIL::SigSpec sig_a = assign_map(cellport.first->connections["\\A"]);
+ RTLIL::SigSpec sig_b = assign_map(cellport.first->connections["\\B"]);
+ if (!check_state_mux_tree(old_sig, sig_a))
+ return false;
+ for (int i = 0; i < sig_b.width; i += sig_a.width)
+ if (!check_state_mux_tree(old_sig, sig_b.extract(i, sig_a.width)))
+ return false;
+ muxtree_cells.insert(cellport.first);
+ }
+
+ return true;
+}
+
+static bool check_state_users(RTLIL::SigSpec sig)
+{
+ if (sig_at_port.check_any(assign_map(sig)))
+ return false;
+
+ std::set<sig2driver_entry_t> cellport_list;
+ sig2user.find(sig, cellport_list);
+ for (auto &cellport : cellport_list) {
+ RTLIL::Cell *cell = cellport.first;
+ if (muxtree_cells.count(cell) > 0)
+ continue;
+ if (cellport.second != "\\A" && cellport.second != "\\B")
+ return false;
+ if (cell->connections.count("\\A") == 0 || cell->connections.count("\\B") == 0 || cell->connections.count("\\Y") == 0)
+ return false;
+ for (auto &port_it : cell->connections)
+ if (port_it.first != "\\A" && port_it.first != "\\B" && port_it.first != "\\Y")
+ return false;
+ if (assign_map(cell->connections["\\A"]) == sig && cell->connections["\\B"].is_fully_const())
+ continue;
+ if (assign_map(cell->connections["\\B"]) == sig && cell->connections["\\A"].is_fully_const())
+ continue;
+ return false;
+ }
+
+ return true;
+}
+
+static void detect_fsm(RTLIL::Wire *wire)
+{
+ if (wire->attributes.count("\\fsm_encoding") > 0 || wire->width <= 1)
+ return;
+ if (sig_at_port.check_any(assign_map(RTLIL::SigSpec(wire))))
+ return;
+
+ std::set<sig2driver_entry_t> cellport_list;
+ sig2driver.find(RTLIL::SigSpec(wire), cellport_list);
+ for (auto &cellport : cellport_list) {
+ if ((cellport.first->type != "$dff" && cellport.first->type != "$adff") || cellport.second != "\\Q")
+ continue;
+ muxtree_cells.clear();
+ RTLIL::SigSpec sig_q = assign_map(cellport.first->connections["\\Q"]);
+ RTLIL::SigSpec sig_d = assign_map(cellport.first->connections["\\D"]);
+ if (sig_q == RTLIL::SigSpec(wire) && check_state_mux_tree(sig_q, sig_d) && check_state_users(sig_q)) {
+ log("Found FSM state register %s in module %s.\n", wire->name.c_str(), module->name.c_str());
+ wire->attributes["\\fsm_encoding"] = RTLIL::Const("auto");
+ return;
+ }
+ }
+}
+
+struct FsmDetectPass : public Pass {
+ FsmDetectPass() : Pass("fsm_detect") { }
+ virtual void execute(std::vector<std::string> args, RTLIL::Design *design)
+ {
+ log_header("Executing FSM_DETECT pass (finding FSMs in design).\n");
+ extra_args(args, 1, design);
+
+ CellTypes ct;
+ ct.setup_internals();
+ ct.setup_internals_mem();
+ ct.setup_stdcells();
+ ct.setup_stdcells_mem();
+
+ for (auto &mod_it : design->modules)
+ {
+ module = mod_it.second;
+ assign_map.set(module);
+
+ sig2driver.clear();
+ sig2user.clear();
+ sig_at_port.clear();
+ for (auto &cell_it : module->cells)
+ for (auto &conn_it : cell_it.second->connections) {
+ if (ct.cell_output(cell_it.second->type, conn_it.first)) {
+ RTLIL::SigSpec sig = conn_it.second;
+ assign_map.apply(sig);
+ sig2driver.insert(sig, sig2driver_entry_t(cell_it.second, conn_it.first));
+ }
+ if (!ct.cell_known(cell_it.second->type) || ct.cell_input(cell_it.second->type, conn_it.first)) {
+ RTLIL::SigSpec sig = conn_it.second;
+ assign_map.apply(sig);
+ sig2user.insert(sig, sig2driver_entry_t(cell_it.second, conn_it.first));
+ }
+ }
+
+ for (auto &wire_it : module->wires)
+ if (wire_it.second->port_id != 0)
+ sig_at_port.add(assign_map(RTLIL::SigSpec(wire_it.second)));
+
+ for (auto &wire_it : module->wires)
+ detect_fsm(wire_it.second);
+ }
+
+ assign_map.clear();
+ sig2driver.clear();
+ sig2user.clear();
+ muxtree_cells.clear();
+ }
+} FsmDetectPass;
+