Added dffsr2dff

2 files changed, 169 insertions, 0 deletions

diff --git a/passes/techmap/Makefile.inc b/passes/techmap/Makefile.inc
index fa938868..8112516c 100644
--- a/passes/techmap/Makefile.inc
+++ b/passes/techmap/Makefile.inc
@@ -22,6 +22,7 @@ OBJS += passes/techmap/aigmap.o
 OBJS += passes/techmap/tribuf.o
 OBJS += passes/techmap/lut2mux.o
 OBJS += passes/techmap/nlutmap.o
+OBJS += passes/techmap/dffsr2dff.o
 endif
 
 GENFILES += passes/techmap/techmap.inc
diff --git a/passes/techmap/dffsr2dff.cc b/passes/techmap/dffsr2dff.cc
new file mode 100644
index 00000000..a9c90a9e
--- /dev/null
+++ b/passes/techmap/dffsr2dff.cc
@@ -0,0 +1,168 @@
+/*
+ *  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/yosys.h"
+#include "kernel/sigtools.h"
+
+USING_YOSYS_NAMESPACE
+PRIVATE_NAMESPACE_BEGIN
+
+void dffsr2dff_worker(SigMap &sigmap, Module *module, Cell *cell)
+{
+	if (cell->type == "$dffsr")
+	{
+		int width = cell->getParam("\\WIDTH").as_int();
+		bool setpol = cell->getParam("\\SET_POLARITY").as_bool();
+		bool clrpol = cell->getParam("\\CLR_POLARITY").as_bool();
+
+		SigBit setunused = setpol ? State::S0 : State::S1;
+		SigBit clrunused = clrpol ? State::S0 : State::S1;
+
+		SigSpec setsig = sigmap(cell->getPort("\\SET"));
+		SigSpec clrsig = sigmap(cell->getPort("\\CLR"));
+
+		Const reset_val;
+		SigSpec setctrl, clrctrl;
+
+		for (int i = 0; i < width; i++)
+		{
+			SigBit setbit = setsig[i], clrbit = clrsig[i];
+
+			if (setbit == setunused) {
+				clrctrl.append(clrbit);
+				reset_val.bits.push_back(State::S0);
+				continue;
+			}
+
+			if (clrbit == clrunused) {
+				setctrl.append(setbit);
+				reset_val.bits.push_back(State::S1);
+				continue;
+			}
+
+			return;
+		}
+
+		setctrl.sort_and_unify();
+		clrctrl.sort_and_unify();
+
+		if (GetSize(setctrl) > 1 || GetSize(clrctrl) > 1)
+			return;
+
+		if (GetSize(setctrl) == 0 && GetSize(clrctrl) == 0)
+			return;
+
+		if (GetSize(setctrl) == 1 && GetSize(clrctrl) == 1) {
+			if (setpol != clrpol)
+				return;
+			if (setctrl != clrctrl)
+				return;
+		}
+
+		log("Converting %s cell %s.%s to $adff.\n", log_id(cell->type), log_id(module), log_id(cell));
+
+		if (GetSize(setctrl) == 1) {
+			cell->setPort("\\ARST", setctrl);
+			cell->setParam("\\ARST_POLARITY", setpol);
+		} else {
+			cell->setPort("\\ARST", clrctrl);
+			cell->setParam("\\ARST_POLARITY", clrpol);
+		}
+
+		cell->type = "$adff";
+		cell->unsetPort("\\SET");
+		cell->unsetPort("\\CLR");
+		cell->setParam("\\ARST_VALUE", reset_val);
+		cell->unsetParam("\\SET_POLARITY");
+		cell->unsetParam("\\CLR_POLARITY");
+
+		return;
+	}
+
+	if (cell->type.in("$_DFFSR_NNN_", "$_DFFSR_NNP_", "$_DFFSR_NPN_", "$_DFFSR_NPP_",
+			"$_DFFSR_PNN_", "$_DFFSR_PNP_", "$_DFFSR_PPN_", "$_DFFSR_PPP_"))
+	{
+		char clkpol = cell->type.c_str()[8];
+		char setpol = cell->type.c_str()[9];
+		char clrpol = cell->type.c_str()[10];
+
+		SigBit setbit = sigmap(cell->getPort("\\S"));
+		SigBit clrbit = sigmap(cell->getPort("\\R"));
+
+		SigBit setunused = setpol == 'P' ? State::S0 : State::S1;
+		SigBit clrunused = clrpol == 'P' ? State::S0 : State::S1;
+
+		IdString oldtype = cell->type;
+
+		if (setbit == setunused) {
+			cell->type = stringf("$_DFF_%c%c0_", clkpol, clrpol);
+			cell->unsetPort("\\S");
+			goto converted_gate;
+		}
+
+		if (clrbit == clrunused) {
+			cell->type = stringf("$_DFF_%c%c1_", clkpol, setpol);
+			cell->setPort("\\R", cell->getPort("\\S"));
+			cell->unsetPort("\\S");
+			goto converted_gate;
+		}
+
+		return;
+
+	converted_gate:
+		log("Converting %s cell %s.%s to %s.\n", log_id(oldtype), log_id(module), log_id(cell), log_id(cell->type));
+		return;
+	}
+}
+
+struct Dffsr2dffPass : public Pass {
+	Dffsr2dffPass() : Pass("dffsr2dff", "convert DFFSR cells to simpler FF cell types") { }
+	virtual void help()
+	{
+		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
+		log("\n");
+		log("    dffsr2dff [options] [selection]\n");
+		log("\n");
+		log("This pass converts DFFSR cells ($dffsr, $_DFFSR_???_) to simpler FF cell types\n");
+		log("when one or both of the set/reset inputs is unused.\n");
+		log("\n");
+	}
+	virtual void execute(std::vector<std::string> args, RTLIL::Design *design)
+	{
+		log_header("Executing DFFSR2DFF pass (mapping DFFSR cells to simpler FFs).\n");
+
+		size_t argidx;
+		for (argidx = 1; argidx < args.size(); argidx++)
+		{
+			// if (args[argidx] == "-v") {
+			// 	continue;
+			// }
+			break;
+		}
+		extra_args(args, argidx, design);
+
+		for (auto module : design->selected_modules()) {
+			SigMap sigmap(module);
+			for (auto cell : module->selected_cells())
+				dffsr2dff_worker(sigmap, module, cell);
+		}
+	}
+} Dffsr2dffPass;
+
+PRIVATE_NAMESPACE_END