yosys/techlibs/ice40/ice40_wrapcarry.cc

/*
 *  yosys -- Yosys Open SYnthesis Suite
 *
 *  Copyright (C) 2012  Claire Xenia Wolf <claire@yosyshq.com>
 *
 *  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

#include "techlibs/ice40/ice40_wrapcarry_pm.h"

void create_ice40_wrapcarry(ice40_wrapcarry_pm &pm)
{
	auto &st = pm.st_ice40_wrapcarry;

#if 0
	log("\n");
	log("carry: %s\n", st.carry ? design->twines.unescaped_str(st.carry->name) : "--");
	log("lut:   %s\n", st.lut ? design->twines.unescaped_str(st.lut->name) : "--");
#endif

	log("  replacing SB_LUT + SB_CARRY with $__ICE40_CARRY_WRAPPER cell.\n");

	Cell *cell = pm.module->addCell(NEW_TWINE, TW($__ICE40_CARRY_WRAPPER));
	pm.module->swap_names(cell, st.carry);

	cell->setPort(TW::A, st.carry->getPort(TW::I0));
	cell->setPort(TW::B, st.carry->getPort(TW::I1));
	auto CI = st.carry->getPort(TW::CI);
	cell->setPort(TW::CI, CI);
	cell->setPort(TW::CO, st.carry->getPort(TW::CO));

	cell->setPort(TW::I0, st.lut->getPort(TW::I0));
	auto I3 = st.lut->getPort(TW::I3);
	if ((*pm.sigmap)(CI) == (*pm.sigmap)(I3)) {
		cell->setParam(ID(I3_IS_CI), State::S1);
		I3 = State::Sx;
	}
	else
		cell->setParam(ID(I3_IS_CI), State::S0);
	cell->setPort(TW::I3, I3);
	cell->setPort(TW::O, st.lut->getPort(TW::O));
	cell->setParam(ID::LUT, st.lut->getParam(ID(LUT_INIT)));

	for (const auto &a : st.carry->attributes)
		cell->attributes[stringf("\\SB_CARRY.%s", a.first)] = a.second;
	for (const auto &a : st.lut->attributes)
		cell->attributes[stringf("\\SB_LUT4.%s", a.first)] = a.second;
	// src now lives in src_id_, not the attributes dict — propagate it
	// via prefixed flat-literal attributes so the unwrap pass can restore.
	if (st.carry->src_id() != Twine::Null)
		cell->attributes[IdString("\\SB_CARRY.\\src")] = Const(st.carry->get_src_attribute());
	if (st.lut->src_id() != Twine::Null)
		cell->attributes[IdString("\\SB_LUT4.\\src")] = Const(st.lut->get_src_attribute());
	// Propagate one of the cell-level srcs to the wrapper too so backends
	// emitting `attribute \src` see a usable value on the wrapper.
	if (cell->module && cell->module->design) {
		if (st.carry->src_id() != Twine::Null)
			cell->set_src_id(st.carry->src_id());
		else if (st.lut->src_id() != Twine::Null)
			cell->set_src_id(st.lut->src_id());
	}
	cell->attributes[IdString{"\\SB_LUT4.name"}] = Const(st.lut->name.str());
	if (st.carry->get_bool_attribute(ID::keep) || st.lut->get_bool_attribute(ID::keep))
		cell->attributes[ID::keep] = true;

	pm.autoremove(st.carry);
	pm.autoremove(st.lut);
}

struct Ice40WrapCarryPass : public Pass {
	Ice40WrapCarryPass() : Pass("ice40_wrapcarry", "iCE40: wrap carries") { }
	void help() override
	{
		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
		log("\n");
		log("    ice40_wrapcarry [selection]\n");
		log("\n");
		log("Wrap manually instantiated SB_CARRY cells, along with their associated SB_LUT4s,\n");
		log("into an internal $__ICE40_CARRY_WRAPPER cell for preservation across technology\n");
		log("mapping.\n");
		log("\n");
		log("Attributes on both cells will have their names prefixed with 'SB_CARRY.' or\n");
		log("'SB_LUT4.' and attached to the wrapping cell.\n");
		log("A (* keep *) attribute on either cell will be logically OR-ed together.\n");
		log("\n");
		log("    -unwrap\n");
		log("        unwrap $__ICE40_CARRY_WRAPPER cells back into SB_CARRYs and SB_LUT4s,\n");
		log("        including restoring their attributes.\n");
		log("\n");
	}
	void execute(std::vector<std::string> args, RTLIL::Design *design) override
	{
		bool unwrap = false;

		log_header(design, "Executing ICE40_WRAPCARRY pass (wrap carries).\n");

		size_t argidx;
		for (argidx = 1; argidx < args.size(); argidx++)
		{
			if (args[argidx] == "-unwrap") {
				unwrap = true;
				continue;
			}
			break;
		}
		extra_args(args, argidx, design);

		// TODO Disabled signorm because swap_names breaks fanout logic
		design->sigNormalize(false);

		for (auto module : design->selected_modules()) {
			if (!unwrap) {
				SigMap sigmap(module);
				ice40_wrapcarry_pm(module, &sigmap, module->selected_cells()).run_ice40_wrapcarry(create_ice40_wrapcarry);
			} else {
				for (auto cell : module->selected_cells()) {
					if (cell->type != TW($__ICE40_CARRY_WRAPPER))
						continue;

					auto carry = module->addCell(NEW_TWINE, ID(SB_CARRY));
					carry->setPort(TW::I0, cell->getPort(TW::A));
					carry->setPort(TW::I1, cell->getPort(TW::B));
					carry->setPort(TW::CI, cell->getPort(TW::CI));
					carry->setPort(TW::CO, cell->getPort(TW::CO));
					module->swap_names(carry, cell);
					auto lut_name = cell->attributes.at(IdString{"\\SB_LUT4.name"}, Const(NEW_ID.str())).decode_string();
					auto lut = module->addCell(lut_name, TW($lut));
					lut->setParam(ID::WIDTH, 4);
					lut->setParam(ID::LUT, cell->getParam(ID::LUT));
					auto I3 = cell->getPort(cell->getParam(ID(I3_IS_CI)).as_bool() ? ID::CI : ID(I3));
					lut->setPort(TW::A, { I3, cell->getPort(TW::B), cell->getPort(TW::A), cell->getPort(TW::I0) });
					lut->setPort(TW::Y, cell->getPort(TW::O));

					std::string carry_src, lut_src, fallback_src;
					if (cell->src_id() != Twine::Null)
						fallback_src = cell->get_src_attribute();
					for (const auto &a : cell->attributes) {
						// Match the prefixed src first so we don't fall through
						// to the generic SB_CARRY./SB_LUT4. prefix copy.
						if (a.first == IdString("\\SB_CARRY.\\src")) {
							carry_src = a.second.decode_string();
						} else if (a.first == IdString("\\SB_LUT4.\\src")) {
							lut_src = a.second.decode_string();
						} else if (a.first.begins_with("\\SB_CARRY.\\")) {
							carry->attributes[a.first.c_str() + strlen("\\SB_CARRY.")] = a.second;
						} else if (a.first.begins_with("\\SB_LUT4.\\")) {
							lut->attributes[a.first.c_str() + strlen("\\SB_LUT4.")] = a.second;
						} else if (a.first.in(IdString{"\\SB_LUT4.name"}, ID::keep, ID::module_not_derived)) {
							continue;
						} else {
							log_abort();
						}
					}
					if (carry_src.empty()) carry_src = fallback_src;
					if (lut_src.empty()) lut_src = fallback_src;
					if (!carry_src.empty()) carry->set_src_attribute(carry_src);
					if (!lut_src.empty()) lut->set_src_attribute(lut_src);

					module->remove(cell);
				}
			}
		}
	}
} Ice40WrapCarryPass;

PRIVATE_NAMESPACE_END