From: Clifford Wolf <clifford@clifford.at>
Date: Thu, 24 Oct 2013 16:20:06 +0000 (+0200)
Subject: Added support for sr flip-flops to dfflibmap
X-Git-Tag: yosys-0.2.0~447
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=dd56004fc06c0ce4786457010fc9c70354ea3381;p=yosys.git

Added support for sr flip-flops to dfflibmap
---

diff --git a/passes/techmap/dfflibmap.cc b/passes/techmap/dfflibmap.cc
index 5e3219d55..111f2f919 100644
--- a/passes/techmap/dfflibmap.cc
+++ b/passes/techmap/dfflibmap.cc
@@ -35,12 +35,14 @@ static void logmap(std::string dff)
 	if (cell_mappings.count(dff) == 0) {
 		log("    unmapped dff cell: %s\n", dff.c_str());
 	} else {
-		log("    %s %s(", cell_mappings[dff].cell_name.c_str(), dff.substr(1).c_str());
+		log("    %s %s (", cell_mappings[dff].cell_name.c_str(), dff.substr(1).c_str());
 		bool first = true;
 		for (auto &port : cell_mappings[dff].ports) {
 			char arg[3] = { port.second, 0, 0 };
 			if ('a' <= arg[0] && arg[0] <= 'z')
 				arg[1] = arg[0] - ('a' - 'A'), arg[0] = '~';
+			else
+				arg[1] = arg[0], arg[0] = ' ';
 			log("%s.%s(%s)", first ? "" : ", ", port.first.c_str(), arg);
 			first = false;
 		}
@@ -52,6 +54,7 @@ static void logmap_all()
 {
 	logmap("$_DFF_N_");
 	logmap("$_DFF_P_");
+
 	logmap("$_DFF_NN0_");
 	logmap("$_DFF_NN1_");
 	logmap("$_DFF_NP0_");
@@ -60,6 +63,15 @@ static void logmap_all()
 	logmap("$_DFF_PN1_");
 	logmap("$_DFF_PP0_");
 	logmap("$_DFF_PP1_");
+
+	logmap("$_DFFSR_NNN_");
+	logmap("$_DFFSR_NNP_");
+	logmap("$_DFFSR_NPN_");
+	logmap("$_DFFSR_NPP_");
+	logmap("$_DFFSR_PNN_");
+	logmap("$_DFFSR_PNP_");
+	logmap("$_DFFSR_PPN_");
+	logmap("$_DFFSR_PPP_");
 }
 
 static bool parse_pin(LibertyAst *cell, LibertyAst *attr, std::string &pin_name, bool &pin_pol)
@@ -175,6 +187,88 @@ static void find_cell(LibertyAst *ast, std::string cell_type, bool clkpol, bool
 	}
 }
 
+static void find_cell_sr(LibertyAst *ast, std::string cell_type, bool clkpol, bool setpol, bool clrpol)
+{
+	LibertyAst *best_cell = NULL;
+	std::map<std::string, char> best_cell_ports;
+	int best_cell_pins = 0;
+
+	if (ast->id != "library")
+		log_error("Format error in liberty file.\n");
+
+	for (auto cell : ast->children)
+	{
+		if (cell->id != "cell" || cell->args.size() != 1)
+			continue;
+
+		LibertyAst *ff = cell->find("ff");
+		if (ff == NULL)
+			continue;
+
+		std::string cell_clk_pin, cell_set_pin, cell_clr_pin, cell_next_pin;
+		bool cell_clk_pol, cell_set_pol, cell_clr_pol, cell_next_pol;
+
+		if (!parse_pin(cell, ff->find("clocked_on"), cell_clk_pin, cell_clk_pol) || cell_clk_pol != clkpol)
+			continue;
+		if (!parse_pin(cell, ff->find("next_state"), cell_next_pin, cell_next_pol))
+			continue;
+		if (!parse_pin(cell, ff->find("preset"), cell_set_pin, cell_set_pol) || cell_set_pol != setpol)
+			continue;
+		if (!parse_pin(cell, ff->find("clear"), cell_clr_pin, cell_clr_pol) || cell_clr_pol != clrpol)
+			continue;
+
+		std::map<std::string, char> this_cell_ports;
+		this_cell_ports[cell_clk_pin] = 'C';
+		this_cell_ports[cell_set_pin] = 'S';
+		this_cell_ports[cell_clr_pin] = 'R';
+		this_cell_ports[cell_next_pin] = 'D';
+
+		int num_pins = 0;
+		bool found_output = false;
+		for (auto pin : cell->children)
+		{
+			if (pin->id != "pin" || pin->args.size() != 1)
+				continue;
+
+			LibertyAst *dir = pin->find("direction");
+			if (dir == NULL || dir->value == "internal")
+				continue;
+			num_pins++;
+
+			if (dir->value == "input" && this_cell_ports.count(pin->args[0]) == 0)
+				goto continue_cell_loop;
+
+			LibertyAst *func = pin->find("function");
+			if (dir->value == "output" && func != NULL) {
+				std::string value = func->value;
+				for (size_t pos = value.find_first_of("\" \t"); pos != std::string::npos; pos = value.find_first_of("\" \t"))
+					value.erase(pos, 1);
+				if ((cell_next_pol == true && value == ff->args[0]) || (cell_next_pol == false && value == ff->args[1])) {
+					this_cell_ports[pin->args[0]] = 'Q';
+					found_output = true;
+				}
+			}
+
+			if (this_cell_ports.count(pin->args[0]) == 0)
+				this_cell_ports[pin->args[0]] = 0;
+		}
+
+		if (!found_output || (best_cell != NULL && num_pins > best_cell_pins))
+			continue;
+
+		best_cell = cell;
+		best_cell_pins = num_pins;
+		best_cell_ports.swap(this_cell_ports);
+	continue_cell_loop:;
+	}
+
+	if (best_cell != NULL) {
+		log("  cell %s is a direct match for cell type %s.\n", best_cell->args[0].c_str(), cell_type.substr(1).c_str());
+		cell_mappings[cell_type].cell_name = best_cell->args[0];
+		cell_mappings[cell_type].ports = best_cell_ports;
+	}
+}
+
 static bool expand_cellmap_worker(std::string from, std::string to, std::string inv)
 {
 	if (cell_mappings.count(to) > 0)
@@ -185,7 +279,10 @@ static bool expand_cellmap_worker(std::string from, std::string to, std::string
 	cell_mappings[to].ports = cell_mappings[from].ports;
 
 	for (auto &it : cell_mappings[to].ports) {
-		if (inv.find(it.second) == std::string::npos)
+		char cmp_ch = it.second;
+		if ('a' <= cmp_ch && cmp_ch <= 'z')
+			cmp_ch -= 'a' - 'A';
+		if (inv.find(cmp_ch) == std::string::npos)
 			continue;
 		if ('a' <= it.second && it.second <= 'z')
 			it.second -= 'a' - 'A';
@@ -223,6 +320,48 @@ static bool expand_cellmap(std::string pattern, std::string inv)
 	return return_status;
 }
 
+static void map_sr_to_arst(const char *from, const char *to)
+{
+	if (cell_mappings.count(to) > 0)
+		return;
+
+	char from_clk_pol = from[8], from_set_pol = from[9], from_clr_pol = from[10];
+	char to_clk_pol = to[6], to_rst_pol = to[7], to_rst_val = to[8];
+
+	log_assert(from_clk_pol == to_clk_pol);
+	log_assert(to_rst_pol == from_set_pol && to_rst_pol == from_clr_pol);
+
+	log("  create mapping for %s from mapping for %s.\n", to, from);
+	cell_mappings[to].cell_name = cell_mappings[from].cell_name;
+	cell_mappings[to].ports = cell_mappings[from].ports;
+
+	for (auto &it : cell_mappings[to].ports)
+	{
+		bool is_set_pin = it.second == 'S' || it.second == 's';
+		bool is_clr_pin = it.second == 'R' || it.second == 'r';
+
+		if (!is_set_pin && !is_clr_pin)
+			continue;
+
+		if ((to_rst_val == '0' && is_set_pin) || (to_rst_val == '1' && is_clr_pin))
+		{
+			// this is the unused set/clr pin -- deactivate it
+			if (is_set_pin)
+				it.second = (from_set_pol == 'P') == (it.second == 'S') ? '0' : '1';
+			else
+				it.second = (from_clr_pol == 'P') == (it.second == 'R') ? '0' : '1';
+		}
+		else
+		{
+			// this is the used set/clr pin -- rename it to 'reset'
+			if (it.second == 'S')
+				it.second = 'R';
+			if (it.second == 's')
+				it.second = 'r';
+		}
+	}
+}
+
 static void dfflibmap(RTLIL::Design *design, RTLIL::Module *module)
 {
 	log("Mapping DFF cells in module `%s':\n", module->name.c_str());
@@ -256,7 +395,11 @@ static void dfflibmap(RTLIL::Design *design, RTLIL::Module *module)
 				inv_cell->connections[port.second == 'q' ? "\\A" : "\\Y"] = sig;
 				module->cells[inv_cell->name] = inv_cell;
 				module->wires[inv_wire->name] = inv_wire;
-			}
+			} else
+			if (port.second == '0' || port.second == '1') {
+				sig = RTLIL::SigSpec(port.second == '0' ? 0 : 1, 1);
+			} else
+				log_abort();
 			new_cell->connections["\\" + port.first] = sig;
 		}
 		stats[stringf("  mapped %%d %s cells to %s cells.\n", cell->type.c_str(), new_cell->type.c_str())]++;
@@ -311,6 +454,7 @@ struct DfflibmapPass : public Pass {
 
 		find_cell(libparser.ast, "$_DFF_N_", false, false, false, false);
 		find_cell(libparser.ast, "$_DFF_P_", true, false, false, false);
+
 		find_cell(libparser.ast, "$_DFF_NN0_", false, true, false, false);
 		find_cell(libparser.ast, "$_DFF_NN1_", false, true, false, true);
 		find_cell(libparser.ast, "$_DFF_NP0_", false, true, true, false);
@@ -320,6 +464,15 @@ struct DfflibmapPass : public Pass {
 		find_cell(libparser.ast, "$_DFF_PP0_", true, true, true, false);
 		find_cell(libparser.ast, "$_DFF_PP1_", true, true, true, true);
 
+		find_cell_sr(libparser.ast, "$_DFFSR_NNN_", false, false, false);
+		find_cell_sr(libparser.ast, "$_DFFSR_NNP_", false, false, true);
+		find_cell_sr(libparser.ast, "$_DFFSR_NPN_", false, true, false);
+		find_cell_sr(libparser.ast, "$_DFFSR_NPP_", false, true, true);
+		find_cell_sr(libparser.ast, "$_DFFSR_PNN_", true, false, false);
+		find_cell_sr(libparser.ast, "$_DFFSR_PNP_", true, false, true);
+		find_cell_sr(libparser.ast, "$_DFFSR_PPN_", true, true, false);
+		find_cell_sr(libparser.ast, "$_DFFSR_PPP_", true, true, true);
+
 		bool keep_running = true;
 		while (keep_running) {
 			keep_running = false;
@@ -327,7 +480,19 @@ struct DfflibmapPass : public Pass {
 			keep_running |= expand_cellmap("$_DFF_*??_", "C");
 			keep_running |= expand_cellmap("$_DFF_?*?_", "R");
 			keep_running |= expand_cellmap("$_DFF_??*_", "DQ");
+			keep_running |= expand_cellmap("$_DFFSR_*??_", "C");
+			keep_running |= expand_cellmap("$_DFFSR_?*?_", "S");
+			keep_running |= expand_cellmap("$_DFFSR_??*_", "R");
 		}
+
+		map_sr_to_arst("$_DFFSR_NNN_", "$_DFF_NN0_");
+		map_sr_to_arst("$_DFFSR_NNN_", "$_DFF_NN1_");
+		map_sr_to_arst("$_DFFSR_NPP_", "$_DFF_NP0_");
+		map_sr_to_arst("$_DFFSR_NPP_", "$_DFF_NP1_");
+		map_sr_to_arst("$_DFFSR_PNN_", "$_DFF_PN0_");
+		map_sr_to_arst("$_DFFSR_PNN_", "$_DFF_PN1_");
+		map_sr_to_arst("$_DFFSR_PPP_", "$_DFF_PP0_");
+		map_sr_to_arst("$_DFFSR_PPP_", "$_DFF_PP1_");
  
  		log("  final dff cell mappings:\n");
  		logmap_all();