1 files changed, 106 insertions, 0 deletions
diff --git a/techlibs/ice40/ice40_unlut.cc b/techlibs/ice40/ice40_unlut.cc
new file mode 100644
index 00000000..2428a8e7
--- /dev/null
+++ b/techlibs/ice40/ice40_unlut.cc
@@ -0,0 +1,106 @@
+/*
+ *  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"
+#include <stdlib.h>
+#include <stdio.h>
+
+USING_YOSYS_NAMESPACE
+PRIVATE_NAMESPACE_BEGIN
+
+static SigBit get_bit_or_zero(const SigSpec &sig)
+{
+	if (GetSize(sig) == 0)
+		return State::S0;
+	return sig[0];
+}
+
+static void run_ice40_unlut(Module *module)
+{
+	SigMap sigmap(module);
+
+	for (auto cell : module->selected_cells())
+	{
+		if (cell->type == "\\SB_LUT4")
+		{
+			SigSpec inbits;
+
+			inbits.append(get_bit_or_zero(cell->getPort("\\I0")));
+			inbits.append(get_bit_or_zero(cell->getPort("\\I1")));
+			inbits.append(get_bit_or_zero(cell->getPort("\\I2")));
+			inbits.append(get_bit_or_zero(cell->getPort("\\I3")));
+			sigmap.apply(inbits);
+
+			log("Mapping SB_LUT4 cell %s.%s to $lut.\n", log_id(module), log_id(cell));
+
+			cell->type ="$lut";
+			cell->setParam("\\WIDTH", 4);
+			cell->setParam("\\LUT", cell->getParam("\\LUT_INIT"));
+			cell->unsetParam("\\LUT_INIT");
+
+			cell->setPort("\\A", SigSpec({
+				get_bit_or_zero(cell->getPort("\\I3")),
+				get_bit_or_zero(cell->getPort("\\I2")),
+				get_bit_or_zero(cell->getPort("\\I1")),
+				get_bit_or_zero(cell->getPort("\\I0"))
+			}));
+			cell->setPort("\\Y", cell->getPort("\\O")[0]);
+			cell->unsetPort("\\I0");
+			cell->unsetPort("\\I1");
+			cell->unsetPort("\\I2");
+			cell->unsetPort("\\I3");
+			cell->unsetPort("\\O");
+
+			cell->check();
+		}
+	}
+}
+
+struct Ice40UnlutPass : public Pass {
+	Ice40UnlutPass() : Pass("ice40_unlut", "iCE40: perform simple optimizations") { }
+	void help() YS_OVERRIDE
+	{
+		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
+		log("\n");
+		log("    ice40_unlut [options] [selection]\n");
+		log("\n");
+		log("This command transforms all SB_LUT4 cells to generic $lut cells.\n");
+		log("\n");
+	}
+	void execute(std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
+	{
+		log_header(design, "Executing ICE40_UNLUT pass (convert SB_LUT4 to $lut).\n");
+		log_push();
+
+		size_t argidx;
+		for (argidx = 1; argidx < args.size(); argidx++) {
+			// if (args[argidx] == "-???") {
+			//  continue;
+			// }
+			break;
+		}
+		extra_args(args, argidx, design);
+
+		for (auto module : design->selected_modules())
+			run_ice40_unlut(module);
+	}
+} Ice40UnlutPass;
+
+PRIVATE_NAMESPACE_END