diff --git a/passes/techmap/Makefile.inc b/passes/techmap/Makefile.inc index ce67b711d..c2b918f00 100644 --- a/passes/techmap/Makefile.inc +++ b/passes/techmap/Makefile.inc @@ -17,6 +17,7 @@ OBJS += passes/techmap/iopadmap.o OBJS += passes/techmap/hilomap.o OBJS += passes/techmap/extract.o OBJS += passes/techmap/extract_fa.o +OBJS += passes/techmap/recover_reduce.o OBJS += passes/techmap/alumacc.o OBJS += passes/techmap/dff2dffe.o OBJS += passes/techmap/dffinit.o diff --git a/passes/techmap/recover_reduce.cc b/passes/techmap/recover_reduce.cc new file mode 100644 index 000000000..bcc31e182 --- /dev/null +++ b/passes/techmap/recover_reduce.cc @@ -0,0 +1,222 @@ +/* + * yosys -- Yosys Open SYnthesis Suite + * + * Copyright (C) 2017 Robert Ou + * + * 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 + +struct RecoverReducePass : public Pass { + enum GateType { + And, + Or, + Xor + }; + + RecoverReducePass() : Pass("recover_reduce", "converts gate chains into $reduce_* cells") { } + virtual void help() + { + // |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---| + log("\n"); + log(" recover_reduce\n"); + log("\n"); + log("converts gate chains into $reduce_* cells\n"); + log("\n"); + log("This command finds chains of $_AND_, $_OR_, and $_XOR_ cells and replaces them\n"); + log("with their corresponding $reduce_* cells. Because this command only operates on\n"); + log("these cell types, it is recommended to map the design to only these cell types\n"); + log("using the `abc -g` command. Note that, in some cases, it may be more effective\n"); + log("to map the design to only $_AND_ cells, run recover_reduce, map the remaining\n"); + log("parts of the design to AND/OR/XOR cells, and run recover_reduce a second time.\n"); + log("\n"); + } + virtual void execute(std::vector args, RTLIL::Design *design) + { + (void)args; + + for (auto module : design->selected_modules()) + { + SigMap sigmap(module); + + // Index all of the nets in the module + dict sig_to_driver; + dict> sig_to_sink; + for (auto cell : module->selected_cells()) + { + for (auto &conn : cell->connections()) + { + if (cell->output(conn.first)) + for (auto bit : sigmap(conn.second)) + sig_to_driver[bit] = cell; + + if (cell->input(conn.first)) + { + for (auto bit : sigmap(conn.second)) + { + if (sig_to_sink.count(bit) == 0) + sig_to_sink[bit] = pool(); + sig_to_sink[bit].insert(cell); + } + } + } + } + + // Need to check if any wires connect to module ports + pool port_sigs; + for (auto wire : module->selected_wires()) + if (wire->port_input || wire->port_output) + for (auto bit : sigmap(wire)) + port_sigs.insert(bit); + + // Actual logic starts here + pool consumed_cells; + for (auto cell : module->selected_cells()) + { + if (consumed_cells.count(cell)) + continue; + + GateType gt; + + if (cell->type == "$_AND_") + gt = GateType::And; + else if (cell->type == "$_OR_") + gt = GateType::Or; + else if (cell->type == "$_XOR_") + gt = GateType::Xor; + else + continue; + + log("Working on cell %s...\n", cell->name.c_str()); + + // Go all the way to the sink + Cell* head_cell = cell; + Cell* x = cell; + while (true) + { + if (!((x->type == "$_AND_" && gt == GateType::And) || + (x->type == "$_OR_" && gt == GateType::Or) || + (x->type == "$_XOR_" && gt == GateType::Xor))) + break; + + head_cell = x; + + auto y = sigmap(x->getPort("\\Y")); + log_assert(y.size() == 1); + + // Should only continue if there is one fanout back into a cell (not to a port) + if (sig_to_sink[y[0]].size() != 1) + break; + + x = *sig_to_sink[y[0]].begin(); + } + + log(" Head cell is %s\n", head_cell->name.c_str()); + + pool cur_supercell; + std::deque bfs_queue = {head_cell}; + while (bfs_queue.size()) + { + Cell* x = bfs_queue.front(); + bfs_queue.pop_front(); + + cur_supercell.insert(x); + + auto a = sigmap(x->getPort("\\A")); + log_assert(a.size() == 1); + // Must have only one sink + // XXX: Check that it is indeed this node? + if (sig_to_sink[a[0]].size() + port_sigs.count(a[0]) == 1) + { + Cell* cell_a = sig_to_driver[a[0]]; + if (((cell_a->type == "$_AND_" && gt == GateType::And) || + (cell_a->type == "$_OR_" && gt == GateType::Or) || + (cell_a->type == "$_XOR_" && gt == GateType::Xor))) + { + // The cell here is the correct type, and it's definitely driving only + // this current cell. + bfs_queue.push_back(cell_a); + } + } + + auto b = sigmap(x->getPort("\\B")); + log_assert(b.size() == 1); + // Must have only one sink + // XXX: Check that it is indeed this node? + if (sig_to_sink[b[0]].size() + port_sigs.count(b[0]) == 1) + { + Cell* cell_b = sig_to_driver[b[0]]; + if (((cell_b->type == "$_AND_" && gt == GateType::And) || + (cell_b->type == "$_OR_" && gt == GateType::Or) || + (cell_b->type == "$_XOR_" && gt == GateType::Xor))) + { + // The cell here is the correct type, and it's definitely driving only + // this current cell. + bfs_queue.push_back(cell_b); + } + } + } + + log(" Cells:\n"); + for (auto x : cur_supercell) + log(" %s\n", x->name.c_str()); + + if (cur_supercell.size() > 1) + { + // Worth it to create reduce cell + log(" Creating $reduce_* cell!\n"); + + pool input_pool; + pool input_pool_intermed; + for (auto x : cur_supercell) + { + input_pool.insert(sigmap(x->getPort("\\A"))[0]); + input_pool.insert(sigmap(x->getPort("\\B"))[0]); + input_pool_intermed.insert(sigmap(x->getPort("\\Y"))[0]); + } + SigSpec input; + for (auto b : input_pool) + if (input_pool_intermed.count(b) == 0) + input.append_bit(b); + + SigBit output = sigmap(head_cell->getPort("\\Y")[0]); + + auto new_reduce_cell = module->addCell(NEW_ID, + gt == GateType::And ? "$reduce_and" : + gt == GateType::Or ? "$reduce_or" : + gt == GateType::Xor ? "$reduce_xor" : ""); + new_reduce_cell->setParam("\\A_SIGNED", 0); + new_reduce_cell->setParam("\\A_WIDTH", input.size()); + new_reduce_cell->setParam("\\Y_WIDTH", 1); + new_reduce_cell->setPort("\\A", input); + new_reduce_cell->setPort("\\Y", output); + + for (auto x : cur_supercell) + consumed_cells.insert(x); + } + } + + // Remove every cell that we've used up + for (auto cell : consumed_cells) + module->remove(cell); + } + } +} RecoverReducePass; + +PRIVATE_NAMESPACE_END