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Diffstat (limited to 'passes/techmap/lut2mux.cc')
-rw-r--r-- | passes/techmap/lut2mux.cc | 93 |
1 files changed, 93 insertions, 0 deletions
diff --git a/passes/techmap/lut2mux.cc b/passes/techmap/lut2mux.cc new file mode 100644 index 000000000..fe55e499a --- /dev/null +++ b/passes/techmap/lut2mux.cc @@ -0,0 +1,93 @@ +/* + * 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 + +int lut2mux(Cell *cell) +{ + SigSpec sig_a = cell->getPort("\\A"); + SigSpec sig_y = cell->getPort("\\Y"); + Const lut = cell->getParam("\\LUT"); + int count = 1; + + if (GetSize(sig_a) == 1) + { + cell->module->addMuxGate(NEW_ID, lut[0], lut[1], sig_a, sig_y); + } + else + { + SigSpec sig_a_hi = sig_a[GetSize(sig_a)-1]; + SigSpec sig_a_lo = sig_a.extract(0, GetSize(sig_a)-1); + SigSpec sig_y1 = cell->module->addWire(NEW_ID); + SigSpec sig_y2 = cell->module->addWire(NEW_ID); + + Const lut1 = lut.extract(0, GetSize(lut)/2); + Const lut2 = lut.extract(GetSize(lut)/2, GetSize(lut)/2); + + count += lut2mux(cell->module->addLut(NEW_ID, sig_a_lo, sig_y1, lut1)); + count += lut2mux(cell->module->addLut(NEW_ID, sig_a_lo, sig_y2, lut2)); + + cell->module->addMuxGate(NEW_ID, sig_y1, sig_y2, sig_a_hi, sig_y); + } + + cell->module->remove(cell); + return count; +} + +struct Lut2muxPass : public Pass { + Lut2muxPass() : Pass("lut2mux", "convert $lut to $_MUX_") { } + virtual void help() + { + // |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---| + log("\n"); + log(" lut2mux [options] [selection]\n"); + log("\n"); + log("This pass converts $lut cells to $_MUX_ gates.\n"); + log("\n"); + } + virtual void execute(std::vector<std::string> args, RTLIL::Design *design) + { + log_header("Executing LUT2MUX pass (mapping to constant drivers).\n"); + + size_t argidx; + for (argidx = 1; argidx < args.size(); argidx++) + { + // if (args[argidx] == "-v") { + // continue; + // } + break; + } + extra_args(args, argidx, design); + + for (auto module : design->selected_modules()) + for (auto cell : module->selected_cells()) { + if (cell->type == "$lut") { + IdString cell_name = cell->name; + int count = lut2mux(cell); + log("Converted %s.%s to %d MUX cells.\n", log_id(module), log_id(cell_name), count); + } + } + } +} Lut2muxPass; + +PRIVATE_NAMESPACE_END |