aboutsummaryrefslogtreecommitdiffstats
path: root/passes/fsm/fsm_expand.cc
diff options
context:
space:
mode:
Diffstat (limited to 'passes/fsm/fsm_expand.cc')
-rw-r--r--passes/fsm/fsm_expand.cc255
1 files changed, 255 insertions, 0 deletions
diff --git a/passes/fsm/fsm_expand.cc b/passes/fsm/fsm_expand.cc
new file mode 100644
index 000000000..0d5bc7695
--- /dev/null
+++ b/passes/fsm/fsm_expand.cc
@@ -0,0 +1,255 @@
+/*
+ * 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"
+#include <string.h>
+
+struct FsmExpand
+{
+ RTLIL::Module *module;
+ RTLIL::Cell *fsm_cell;
+ SigMap assign_map;
+ SigSet<RTLIL::Cell*> sig2driver, sig2user;
+ CellTypes ct;
+
+ std::set<RTLIL::Cell*> merged_set;
+ std::set<RTLIL::Cell*> current_set;
+ std::set<RTLIL::Cell*> no_candidate_set;
+
+ bool already_optimized;
+ int limit_transitions;
+
+ bool is_cell_merge_candidate(RTLIL::Cell *cell)
+ {
+ RTLIL::SigSpec new_signals;
+ if (cell->connections.count("\\A") > 0)
+ new_signals.append(assign_map(cell->connections["\\A"]));
+ if (cell->connections.count("\\B") > 0)
+ new_signals.append(assign_map(cell->connections["\\B"]));
+ if (cell->connections.count("\\S") > 0)
+ new_signals.append(assign_map(cell->connections["\\S"]));
+
+ new_signals.sort_and_unify();
+ new_signals.remove_const();
+
+ if (new_signals.width > 4)
+ return false;
+
+ new_signals.remove(assign_map(fsm_cell->connections["\\CTRL_IN"]));
+ new_signals.remove(assign_map(fsm_cell->connections["\\CTRL_OUT"]));
+
+ if (cell->connections.count("\\Y") > 0) {
+ new_signals.append(assign_map(cell->connections["\\Y"]));
+ new_signals.sort_and_unify();
+ new_signals.remove_const();
+ new_signals.remove(assign_map(fsm_cell->connections["\\CTRL_IN"]));
+ new_signals.remove(assign_map(fsm_cell->connections["\\CTRL_OUT"]));
+ }
+
+ if (new_signals.width > 2)
+ return false;
+
+ return true;
+ }
+
+ void create_current_set()
+ {
+ std::vector<RTLIL::Cell*> cell_list;
+
+ for (auto c : sig2driver.find(assign_map(fsm_cell->connections["\\CTRL_IN"])))
+ cell_list.push_back(c);
+
+ for (auto c : sig2user.find(assign_map(fsm_cell->connections["\\CTRL_OUT"])))
+ cell_list.push_back(c);
+
+ current_set.clear();
+ for (auto c : cell_list)
+ {
+ if (merged_set.count(c) > 0 || current_set.count(c) > 0 || no_candidate_set.count(c) > 0)
+ continue;
+ for (auto &p : c->connections) {
+ if (p.first != "\\A" && p.first != "\\B" && p.first != "\\S" && p.first != "\\Y")
+ goto next_cell;
+ }
+ if (!is_cell_merge_candidate(c)) {
+ no_candidate_set.insert(c);
+ continue;
+ }
+ current_set.insert(c);
+ next_cell:;
+ }
+ }
+
+ void optimze_as_needed()
+ {
+ if (already_optimized)
+ return;
+
+ int trans_num = fsm_cell->parameters["\\TRANS_NUM"].as_int();
+ if (trans_num > limit_transitions)
+ {
+ log(" grown transition table to %d entries -> optimize.\n", trans_num);
+ FsmData::optimize_fsm(fsm_cell, module);
+ already_optimized = true;
+
+ trans_num = fsm_cell->parameters["\\TRANS_NUM"].as_int();
+ log(" transition table size after optimizaton: %d\n", trans_num);
+ limit_transitions = 16 * trans_num;
+ }
+ }
+
+ void merge_cell_into_fsm(RTLIL::Cell *cell)
+ {
+ optimze_as_needed();
+
+ log(" merging %s cell %s.\n", cell->type.c_str(), cell->name.c_str());
+ merged_set.insert(cell);
+ already_optimized = false;
+
+ RTLIL::SigSpec input_sig, output_sig;
+
+ for (auto &p : cell->connections)
+ if (ct.cell_output(cell->type, p.first))
+ output_sig.append(assign_map(p.second));
+ else
+ input_sig.append(assign_map(p.second));
+ input_sig.sort_and_unify();
+ input_sig.remove_const();
+
+ assert(input_sig.width <= 4);
+ std::vector<RTLIL::Const> truth_tab;
+
+ for (int i = 0; i < (1 << input_sig.width); i++) {
+ RTLIL::Const in_val(i, input_sig.width);
+ RTLIL::SigSpec A, B, S;
+ if (cell->connections.count("\\A") > 0)
+ A = assign_map(cell->connections["\\A"]);
+ if (cell->connections.count("\\B") > 0)
+ B = assign_map(cell->connections["\\B"]);
+ if (cell->connections.count("\\S") > 0)
+ S = assign_map(cell->connections["\\S"]);
+ A.replace(input_sig, RTLIL::SigSpec(in_val));
+ B.replace(input_sig, RTLIL::SigSpec(in_val));
+ S.replace(input_sig, RTLIL::SigSpec(in_val));
+ assert(A.is_fully_const());
+ assert(B.is_fully_const());
+ assert(S.is_fully_const());
+ truth_tab.push_back(ct.eval(cell, A.as_const(), B.as_const(), S.as_const()));
+ }
+
+ FsmData fsm_data;
+ fsm_data.copy_from_cell(fsm_cell);
+
+ fsm_data.num_inputs += input_sig.width;
+ fsm_cell->connections["\\CTRL_IN"].append(input_sig);
+
+ fsm_data.num_outputs += output_sig.width;
+ fsm_cell->connections["\\CTRL_OUT"].append(output_sig);
+
+ std::vector<FsmData::transition_t> new_transition_table;
+ for (auto &tr : fsm_data.transition_table) {
+ for (int i = 0; i < (1 << input_sig.width); i++) {
+ FsmData::transition_t new_tr = tr;
+ RTLIL::Const in_val(i, input_sig.width);
+ RTLIL::Const out_val = truth_tab[i];
+ RTLIL::SigSpec ctrl_in = new_tr.ctrl_in;
+ RTLIL::SigSpec ctrl_out = new_tr.ctrl_out;
+ ctrl_in.append(in_val);
+ ctrl_out.append(out_val);
+ new_tr.ctrl_in = ctrl_in.as_const();
+ new_tr.ctrl_out = ctrl_out.as_const();
+ new_transition_table.push_back(new_tr);
+ }
+ }
+ fsm_data.transition_table.swap(new_transition_table);
+ new_transition_table.clear();
+
+ fsm_data.copy_to_cell(fsm_cell);
+ }
+
+ FsmExpand(RTLIL::Cell *cell, RTLIL::Module *mod)
+ {
+ module = mod;
+ fsm_cell = cell;
+
+ assign_map.set(module);
+ ct.setup_internals();
+
+ for (auto &cell_it : module->cells) {
+ RTLIL::Cell *c = cell_it.second;
+ if (ct.cell_known(c->type))
+ for (auto &p : c->connections) {
+ if (ct.cell_output(c->type, p.first))
+ sig2driver.insert(assign_map(p.second), c);
+ else
+ sig2user.insert(assign_map(p.second), c);
+ }
+ }
+ }
+
+ void execute()
+ {
+ log("\n");
+ log("Expanding FSM `%s' from module `%s':\n", fsm_cell->name.c_str(), module->name.c_str());
+
+ already_optimized = false;
+ limit_transitions = 16 * fsm_cell->parameters["\\TRANS_NUM"].as_int();
+
+ for (create_current_set(); current_set.size() > 0; create_current_set()) {
+ for (auto c : current_set)
+ merge_cell_into_fsm(c);
+ }
+
+ for (auto c : merged_set) {
+ module->cells.erase(c->name);
+ delete c;
+ }
+
+ if (merged_set.size() > 0 && !already_optimized)
+ FsmData::optimize_fsm(fsm_cell, module);
+
+ log(" merged %zd cells into FSM.\n", merged_set.size());
+ }
+};
+
+struct FsmExpandPass : public Pass {
+ FsmExpandPass() : Pass("fsm_expand") { }
+ virtual void execute(std::vector<std::string> args, RTLIL::Design *design)
+ {
+ log_header("Executing FSM_EXPAND pass (re-assigning FSM state encoding).\n");
+ extra_args(args, 1, design);
+
+ for (auto &mod_it : design->modules) {
+ std::vector<RTLIL::Cell*> fsm_cells;
+ for (auto &cell_it : mod_it.second->cells)
+ if (cell_it.second->type == "$fsm")
+ fsm_cells.push_back(cell_it.second);
+ for (auto c : fsm_cells) {
+ FsmExpand fsm_expand(c, mod_it.second);
+ fsm_expand.execute();
+ }
+ }
+ }
+} FsmExpandPass;
+
generated by cgit v1.2.3 (git 2.25.1) at 2024-10-11 16:02:41 +0000