From dafe04d5590412cc8a95bee31810d96a358af3dd Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marcelina=20Ko=C5=9Bcielnicka?= <mwk@0x04.net>
Date: Sun, 19 Jul 2020 03:51:05 +0200
Subject: Add utility module for representing flip-flops.

---
 Makefile    |   1 +
 kernel/ff.h | 440 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 441 insertions(+)
 create mode 100644 kernel/ff.h

diff --git a/Makefile b/Makefile
index 90f8fee05..d6b421920 100644
--- a/Makefile
+++ b/Makefile
@@ -585,6 +585,7 @@ $(eval $(call add_include_file,kernel/modtools.h))
 $(eval $(call add_include_file,kernel/macc.h))
 $(eval $(call add_include_file,kernel/utils.h))
 $(eval $(call add_include_file,kernel/satgen.h))
+$(eval $(call add_include_file,kernel/ff.h))
 $(eval $(call add_include_file,kernel/ffinit.h))
 $(eval $(call add_include_file,libs/ezsat/ezsat.h))
 $(eval $(call add_include_file,libs/ezsat/ezminisat.h))
diff --git a/kernel/ff.h b/kernel/ff.h
new file mode 100644
index 000000000..8dc83eb49
--- /dev/null
+++ b/kernel/ff.h
@@ -0,0 +1,440 @@
+/*
+ *  yosys -- Yosys Open SYnthesis Suite
+ *
+ *  Copyright (C) 2020  Marcelina Kościelnicka <mwk@0x04.net>
+ *
+ *  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.
+ *
+ */
+
+#ifndef FF_H
+#define FF_H
+
+#include "kernel/yosys.h"
+#include "kernel/ffinit.h"
+
+YOSYS_NAMESPACE_BEGIN
+
+struct FfData {
+	FfInitVals *initvals;
+	SigSpec sig_q;
+	SigSpec sig_d;
+	SigSpec sig_clk;
+	SigSpec sig_en;
+	SigSpec sig_arst;
+	SigSpec sig_srst;
+	SigSpec sig_clr;
+	SigSpec sig_set;
+	bool has_d;
+	bool has_clk;
+	bool has_en;
+	bool has_srst;
+	bool has_arst;
+	bool has_sr;
+	bool ce_over_srst;
+	bool is_fine;
+	bool pol_clk;
+	bool pol_en;
+	bool pol_arst;
+	bool pol_srst;
+	bool pol_clr;
+	bool pol_set;
+	Const val_arst;
+	Const val_srst;
+	Const val_init;
+	Const val_d;
+	bool d_is_const;
+	int width;
+	dict<IdString, Const> attributes;
+
+	FfData(FfInitVals *initvals, Cell *cell = nullptr) : initvals(initvals) {
+		width = 0;
+		has_d = true;
+		has_clk = false;
+		has_en = false;
+		has_srst = false;
+		has_arst = false;
+		has_sr = false;
+		ce_over_srst = false;
+		is_fine = false;
+		pol_clk = false;
+		pol_en = false;
+		pol_arst = false;
+		pol_srst = false;
+		pol_clr = false;
+		pol_set = false;
+		d_is_const = false;
+
+		if (!cell)
+			return;
+
+		sig_q = cell->getPort(ID::Q);
+		width = GetSize(sig_q);
+		attributes = cell->attributes;
+
+		if (initvals)
+			val_init = (*initvals)(sig_q);
+
+		std::string type_str = cell->type.str();
+
+		if (cell->type.in(ID($ff), ID($dff), ID($dffe), ID($dffsr), ID($dffsre), ID($adff), ID($adffe), ID($sdff), ID($sdffe), ID($sdffce), ID($dlatch), ID($adlatch), ID($dlatchsr), ID($sr))) {
+			if (cell->type == ID($sr)) {
+				has_d = false;
+			} else {
+				sig_d = cell->getPort(ID::D);
+			}
+			if (!cell->type.in(ID($ff), ID($dlatch), ID($adlatch), ID($dlatchsr), ID($sr))) {
+				has_clk = true;
+				sig_clk = cell->getPort(ID::CLK);
+				pol_clk = cell->getParam(ID::CLK_POLARITY).as_bool();
+			}
+			if (cell->type.in(ID($dffe), ID($dffsre), ID($adffe), ID($sdffe), ID($sdffce), ID($dlatch), ID($adlatch), ID($dlatchsr))) {
+				has_en = true;
+				sig_en = cell->getPort(ID::EN);
+				pol_en = cell->getParam(ID::EN_POLARITY).as_bool();
+			}
+			if (cell->type.in(ID($dffsr), ID($dffsre), ID($dlatchsr), ID($sr))) {
+				has_sr = true;
+				sig_clr = cell->getPort(ID::CLR);
+				sig_set = cell->getPort(ID::SET);
+				pol_clr = cell->getParam(ID::CLR_POLARITY).as_bool();
+				pol_set = cell->getParam(ID::SET_POLARITY).as_bool();
+			}
+			if (cell->type.in(ID($adff), ID($adffe), ID($adlatch))) {
+				has_arst = true;
+				sig_arst = cell->getPort(ID::ARST);
+				pol_arst = cell->getParam(ID::ARST_POLARITY).as_bool();
+				val_arst = cell->getParam(ID::ARST_VALUE);
+			}
+			if (cell->type.in(ID($sdff), ID($sdffe), ID($sdffce))) {
+				has_srst = true;
+				sig_srst = cell->getPort(ID::SRST);
+				pol_srst = cell->getParam(ID::SRST_POLARITY).as_bool();
+				val_srst = cell->getParam(ID::SRST_VALUE);
+				ce_over_srst = cell->type == ID($sdffce);
+			}
+		} else if (cell->type == ID($_FF_)) {
+			is_fine = true;
+			sig_d = cell->getPort(ID::D);
+		} else if (type_str.substr(0, 5) == "$_SR_") {
+			is_fine = true;
+			has_d = false;
+			has_sr = true;
+			pol_set = type_str[5] == 'P';
+			pol_clr = type_str[6] == 'P';
+			sig_set = cell->getPort(ID::S);
+			sig_clr = cell->getPort(ID::R);
+		} else if (type_str.substr(0, 6) == "$_DFF_" && type_str.size() == 8) {
+			is_fine = true;
+			sig_d = cell->getPort(ID::D);
+			has_clk = true;
+			pol_clk = type_str[6] == 'P';
+			sig_clk = cell->getPort(ID::C);
+		} else if (type_str.substr(0, 7) == "$_DFFE_" && type_str.size() == 10) {
+			is_fine = true;
+			sig_d = cell->getPort(ID::D);
+			has_clk = true;
+			pol_clk = type_str[7] == 'P';
+			sig_clk = cell->getPort(ID::C);
+			has_en = true;
+			pol_en = type_str[8] == 'P';
+			sig_en = cell->getPort(ID::E);
+		} else if (type_str.substr(0, 6) == "$_DFF_" && type_str.size() == 10) {
+			is_fine = true;
+			sig_d = cell->getPort(ID::D);
+			has_clk = true;
+			pol_clk = type_str[6] == 'P';
+			sig_clk = cell->getPort(ID::C);
+			has_arst = true;
+			pol_arst = type_str[7] == 'P';
+			sig_arst = cell->getPort(ID::R);
+			val_arst = type_str[8] == '1' ? State::S1 : State::S0;
+		} else if (type_str.substr(0, 7) == "$_DFFE_" && type_str.size() == 12) {
+			is_fine = true;
+			sig_d = cell->getPort(ID::D);
+			has_clk = true;
+			pol_clk = type_str[7] == 'P';
+			sig_clk = cell->getPort(ID::C);
+			has_arst = true;
+			pol_arst = type_str[8] == 'P';
+			sig_arst = cell->getPort(ID::R);
+			val_arst = type_str[9] == '1' ? State::S1 : State::S0;
+			has_en = true;
+			pol_en = type_str[10] == 'P';
+			sig_en = cell->getPort(ID::E);
+		} else if (type_str.substr(0, 8) == "$_DFFSR_" && type_str.size() == 12) {
+			is_fine = true;
+			sig_d = cell->getPort(ID::D);
+			has_clk = true;
+			pol_clk = type_str[8] == 'P';
+			sig_clk = cell->getPort(ID::C);
+			has_sr = true;
+			pol_set = type_str[9] == 'P';
+			pol_clr = type_str[10] == 'P';
+			sig_set = cell->getPort(ID::S);
+			sig_clr = cell->getPort(ID::R);
+		} else if (type_str.substr(0, 9) == "$_DFFSRE_" && type_str.size() == 14) {
+			is_fine = true;
+			sig_d = cell->getPort(ID::D);
+			has_clk = true;
+			pol_clk = type_str[9] == 'P';
+			sig_clk = cell->getPort(ID::C);
+			has_sr = true;
+			pol_set = type_str[10] == 'P';
+			pol_clr = type_str[11] == 'P';
+			sig_set = cell->getPort(ID::S);
+			sig_clr = cell->getPort(ID::R);
+			has_en = true;
+			pol_en = type_str[12] == 'P';
+			sig_en = cell->getPort(ID::E);
+		} else if (type_str.substr(0, 7) == "$_SDFF_" && type_str.size() == 11) {
+			is_fine = true;
+			sig_d = cell->getPort(ID::D);
+			has_clk = true;
+			pol_clk = type_str[7] == 'P';
+			sig_clk = cell->getPort(ID::C);
+			has_srst = true;
+			pol_srst = type_str[8] == 'P';
+			sig_srst = cell->getPort(ID::R);
+			val_srst = type_str[9] == '1' ? State::S1 : State::S0;
+		} else if (type_str.substr(0, 8) == "$_SDFFE_" && type_str.size() == 13) {
+			is_fine = true;
+			sig_d = cell->getPort(ID::D);
+			has_clk = true;
+			pol_clk = type_str[8] == 'P';
+			sig_clk = cell->getPort(ID::C);
+			has_srst = true;
+			pol_srst = type_str[9] == 'P';
+			sig_srst = cell->getPort(ID::R);
+			val_srst = type_str[10] == '1' ? State::S1 : State::S0;
+			has_en = true;
+			pol_en = type_str[11] == 'P';
+			sig_en = cell->getPort(ID::E);
+		} else if (type_str.substr(0, 9) == "$_SDFFCE_" && type_str.size() == 14) {
+			is_fine = true;
+			sig_d = cell->getPort(ID::D);
+			has_clk = true;
+			pol_clk = type_str[9] == 'P';
+			sig_clk = cell->getPort(ID::C);
+			has_srst = true;
+			pol_srst = type_str[10] == 'P';
+			sig_srst = cell->getPort(ID::R);
+			val_srst = type_str[11] == '1' ? State::S1 : State::S0;
+			has_en = true;
+			pol_en = type_str[12] == 'P';
+			sig_en = cell->getPort(ID::E);
+			ce_over_srst = true;
+		} else if (type_str.substr(0, 9) == "$_DLATCH_" && type_str.size() == 11) {
+			is_fine = true;
+			sig_d = cell->getPort(ID::D);
+			has_en = true;
+			pol_en = type_str[9] == 'P';
+			sig_en = cell->getPort(ID::E);
+		} else if (type_str.substr(0, 9) == "$_DLATCH_" && type_str.size() == 13) {
+			is_fine = true;
+			sig_d = cell->getPort(ID::D);
+			has_en = true;
+			pol_en = type_str[9] == 'P';
+			sig_en = cell->getPort(ID::E);
+			has_arst = true;
+			pol_arst = type_str[10] == 'P';
+			sig_arst = cell->getPort(ID::R);
+			val_arst = type_str[11] == '1' ? State::S1 : State::S0;
+		} else if (type_str.substr(0, 11) == "$_DLATCHSR_" && type_str.size() == 15) {
+			is_fine = true;
+			sig_d = cell->getPort(ID::D);
+			has_en = true;
+			pol_en = type_str[11] == 'P';
+			sig_en = cell->getPort(ID::E);
+			has_sr = true;
+			pol_set = type_str[12] == 'P';
+			pol_clr = type_str[13] == 'P';
+			sig_set = cell->getPort(ID::S);
+			sig_clr = cell->getPort(ID::R);
+		} else {
+			log_assert(0);
+		}
+		if (has_d && sig_d.is_fully_const()) {
+			d_is_const = true;
+			val_d = sig_d.as_const();
+			if (has_en && !has_clk && !has_sr && !has_arst) {
+				// Plain D latches with const D treated specially.
+				has_en = has_d = false;
+				has_arst = true;
+				sig_arst = sig_en;
+				pol_arst = pol_en;
+				val_arst = val_d;
+			}
+		}
+	}
+
+	// Returns a FF identical to this one, but only keeping bit indices from the argument.
+	FfData slice(const std::vector<int> &bits) {
+		FfData res(initvals);
+		res.sig_clk = sig_clk;
+		res.sig_en = sig_en;
+		res.sig_arst = sig_arst;
+		res.sig_srst = sig_srst;
+		res.has_d = has_d;
+		res.has_clk = has_clk;
+		res.has_en = has_en;
+		res.has_arst = has_arst;
+		res.has_srst = has_srst;
+		res.has_sr = has_sr;
+		res.ce_over_srst = ce_over_srst;
+		res.is_fine = is_fine;
+		res.pol_clk = pol_clk;
+		res.pol_en = pol_en;
+		res.pol_arst = pol_arst;
+		res.pol_srst = pol_srst;
+		res.pol_clr = pol_clr;
+		res.pol_set = pol_set;
+		res.attributes = attributes;
+		for (int i : bits) {
+			res.sig_q.append(sig_q[i]);
+			if (has_d)
+				res.sig_d.append(sig_d[i]);
+			if (has_sr) {
+				res.sig_clr.append(sig_clr[i]);
+				res.sig_set.append(sig_set[i]);
+			}
+			if (has_arst)
+				res.val_arst.bits.push_back(val_arst[i]);
+			if (has_srst)
+				res.val_srst.bits.push_back(val_srst[i]);
+			res.val_init.bits.push_back(val_init[i]);
+		}
+		res.width = GetSize(res.sig_q);
+		// Slicing bits out may cause D to become const.
+		if (has_d && res.sig_d.is_fully_const()) {
+			res.d_is_const = true;
+			res.val_d = res.sig_d.as_const();
+		}
+		return res;
+	}
+
+	Cell *emit(Module *module, IdString name) {
+		if (!width)
+			return nullptr;
+		if (!has_d && !has_sr) {
+			if (has_arst) {
+				// Convert this case to a D latch.
+				has_d = has_en = true;
+				has_arst = false;
+				sig_d = val_arst;
+				sig_en = sig_arst;
+				pol_en = pol_arst;
+			} else {
+				// No control inputs left.  Turn into a const driver.
+				initvals->remove_init(sig_q);
+				module->connect(sig_q, val_init);
+				return nullptr;
+			}
+		}
+		initvals->set_init(sig_q, val_init);
+		Cell *cell;
+		if (!is_fine) {
+			if (!has_d) {
+				log_assert(has_sr);
+				cell = module->addSr(name, sig_set, sig_clr, sig_q, pol_set, pol_clr);
+			} else if (!has_clk && !has_en) {
+				log_assert(!has_arst);
+				log_assert(!has_srst);
+				log_assert(!has_sr);
+				cell = module->addFf(name, sig_d, sig_q);
+			} else if (!has_clk) {
+				log_assert(!has_srst);
+				if (has_sr)
+					cell = module->addDlatchsr(name, sig_en, sig_set, sig_clr, sig_d, sig_q, pol_en, pol_set, pol_clr);
+				else if (has_arst)
+					cell = module->addAdlatch(name, sig_en, sig_arst, sig_d, sig_q, val_arst, pol_en, pol_arst);
+				else
+					cell = module->addDlatch(name, sig_en, sig_d, sig_q, pol_en);
+			} else {
+				if (has_sr) {
+					if (has_en)
+						cell = module->addDffsre(name, sig_clk, sig_en, sig_set, sig_clr, sig_d, sig_q, pol_clk, pol_en, pol_set, pol_clr);
+					else
+						cell = module->addDffsr(name, sig_clk, sig_set, sig_clr, sig_d, sig_q, pol_clk, pol_set, pol_clr);
+				} else if (has_arst) {
+					if (has_en)
+						cell = module->addAdffe(name, sig_clk, sig_en, sig_arst, sig_d, sig_q, val_arst, pol_clk, pol_en, pol_arst);
+					else
+						cell = module->addAdff(name, sig_clk, sig_arst, sig_d, sig_q, val_arst, pol_clk, pol_arst);
+				} else if (has_srst) {
+					if (has_en)
+						if (ce_over_srst)
+							cell = module->addSdffce(name, sig_clk, sig_en, sig_srst, sig_d, sig_q, val_srst, pol_clk, pol_en, pol_srst);
+						else
+							cell = module->addSdffe(name, sig_clk, sig_en, sig_srst, sig_d, sig_q, val_srst, pol_clk, pol_en, pol_srst);
+					else
+						cell = module->addSdff(name, sig_clk, sig_srst, sig_d, sig_q, val_srst, pol_clk, pol_srst);
+				} else {
+					if (has_en)
+						cell = module->addDffe(name, sig_clk, sig_en, sig_d, sig_q, pol_clk, pol_en);
+					else
+						cell = module->addDff(name, sig_clk, sig_d, sig_q, pol_clk);
+				}
+			}
+		} else {
+			if (!has_d) {
+				log_assert(has_sr);
+				cell = module->addSrGate(name, sig_set, sig_clr, sig_q, pol_set, pol_clr);
+			} else if (!has_clk && !has_en) {
+				log_assert(!has_arst);
+				log_assert(!has_srst);
+				log_assert(!has_sr);
+				cell = module->addFfGate(name, sig_d, sig_q);
+			} else if (!has_clk) {
+				log_assert(!has_srst);
+				if (has_sr)
+					cell = module->addDlatchsrGate(name, sig_en, sig_set, sig_clr, sig_d, sig_q, pol_en, pol_set, pol_clr);
+				else if (has_arst)
+					cell = module->addAdlatchGate(name, sig_en, sig_arst, sig_d, sig_q, val_arst.as_bool(), pol_en, pol_arst);
+				else
+					cell = module->addDlatchGate(name, sig_en, sig_d, sig_q, pol_en);
+			} else {
+				if (has_sr) {
+					if (has_en)
+						cell = module->addDffsreGate(name, sig_clk, sig_en, sig_set, sig_clr, sig_d, sig_q, pol_clk, pol_en, pol_set, pol_clr);
+					else
+						cell = module->addDffsrGate(name, sig_clk, sig_set, sig_clr, sig_d, sig_q, pol_clk, pol_set, pol_clr);
+				} else if (has_arst) {
+					if (has_en)
+						cell = module->addAdffeGate(name, sig_clk, sig_en, sig_arst, sig_d, sig_q, val_arst.as_bool(), pol_clk, pol_en, pol_arst);
+					else
+						cell = module->addAdffGate(name, sig_clk, sig_arst, sig_d, sig_q, val_arst.as_bool(), pol_clk, pol_arst);
+				} else if (has_srst) {
+					if (has_en)
+						if (ce_over_srst)
+							cell = module->addSdffceGate(name, sig_clk, sig_en, sig_srst, sig_d, sig_q, val_srst.as_bool(), pol_clk, pol_en, pol_srst);
+						else
+							cell = module->addSdffeGate(name, sig_clk, sig_en, sig_srst, sig_d, sig_q, val_srst.as_bool(), pol_clk, pol_en, pol_srst);
+					else
+						cell = module->addSdffGate(name, sig_clk, sig_srst, sig_d, sig_q, val_srst.as_bool(), pol_clk, pol_srst);
+				} else {
+					if (has_en)
+						cell = module->addDffeGate(name, sig_clk, sig_en, sig_d, sig_q, pol_clk, pol_en);
+					else
+						cell = module->addDffGate(name, sig_clk, sig_d, sig_q, pol_clk);
+				}
+			}
+		}
+		cell->attributes = attributes;
+		return cell;
+	}
+};
+
+YOSYS_NAMESPACE_END
+
+#endif
-- 
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