diff options
Diffstat (limited to 'passes/opt/opt_rmdff.cc')
| -rw-r--r-- | passes/opt/opt_rmdff.cc | 135 |
1 files changed, 135 insertions, 0 deletions
diff --git a/passes/opt/opt_rmdff.cc b/passes/opt/opt_rmdff.cc new file mode 100644 index 000000000..384a4d85f --- /dev/null +++ b/passes/opt/opt_rmdff.cc @@ -0,0 +1,135 @@ +/* + * 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 "opt_status.h" +#include "kernel/register.h" +#include "kernel/sigtools.h" +#include "kernel/log.h" +#include <stdlib.h> +#include <stdio.h> + +static SigMap assign_map; + +static bool handle_dff(RTLIL::Module *mod, RTLIL::Cell *dff) +{ + RTLIL::SigSpec sig_d, sig_q, sig_c, sig_r; + RTLIL::Const val_cp, val_rp, val_rv; + + if (dff->type == "$_DFF_N_" || dff->type == "$_DFF_P_") { + sig_d = dff->connections["\\D"]; + sig_q = dff->connections["\\Q"]; + sig_c = dff->connections["\\C"]; + val_cp = RTLIL::Const(dff->type == "$_DFF_P_", 1); + } + else if (dff->type.substr(0,6) == "$_DFF_" && dff->type.substr(9) == "_" && + (dff->type[6] == 'N' || dff->type[6] == 'P') && + (dff->type[7] == 'N' || dff->type[7] == 'P') && + (dff->type[8] == '0' || dff->type[8] == '1')) { + sig_d = dff->connections["\\D"]; + sig_q = dff->connections["\\Q"]; + sig_c = dff->connections["\\C"]; + sig_r = dff->connections["\\R"]; + val_cp = RTLIL::Const(dff->type[6] == 'P', 1); + val_rp = RTLIL::Const(dff->type[7] == 'P', 1); + val_rv = RTLIL::Const(dff->type[8] == '1', 1); + } + else if (dff->type == "$dff") { + sig_d = dff->connections["\\D"]; + sig_q = dff->connections["\\Q"]; + sig_c = dff->connections["\\CLK"]; + val_cp = RTLIL::Const(dff->parameters["\\CLK_POLARITY"].as_bool(), 1); + } + else if (dff->type == "$adff") { + sig_d = dff->connections["\\D"]; + sig_q = dff->connections["\\Q"]; + sig_c = dff->connections["\\CLK"]; + sig_r = dff->connections["\\ARST"]; + val_cp = RTLIL::Const(dff->parameters["\\CLK_POLARITY"].as_bool(), 1); + val_rp = RTLIL::Const(dff->parameters["\\ARST_POLARITY"].as_bool(), 1); + val_rv = dff->parameters["\\ARST_VALUE"]; + } + else + log_error("abort."); + + assign_map.apply(sig_d); + assign_map.apply(sig_q); + assign_map.apply(sig_c); + assign_map.apply(sig_r); + + if (sig_d.is_fully_const() && sig_r.width == 0) { + RTLIL::SigSig conn(sig_q, sig_d); + mod->connections.push_back(conn); + goto delete_dff; + } + + if (sig_d == sig_q && sig_r.width == 0) { + goto delete_dff; + } + + return false; + +delete_dff: + log("Removing %s (%s) from module %s.\n", dff->name.c_str(), dff->type.c_str(), mod->name.c_str()); + OPT_DID_SOMETHING = true; + mod->cells.erase(dff->name); + delete dff; + return true; +} + +struct OptRmdffPass : public Pass { + OptRmdffPass() : Pass("opt_rmdff") { } + virtual void execute(std::vector<std::string> args, RTLIL::Design *design) + { + int total_count = 0; + log_header("Executing OPT_RMDFF pass (remove dff with constant values).\n"); + + extra_args(args, 1, design); + + for (auto &mod_it : design->modules) + { + assign_map.set(mod_it.second); + + std::vector<std::string> dff_list; + for (auto &it : mod_it.second->cells) { + if (it.second->type == "$_DFF_N_") dff_list.push_back(it.first); + if (it.second->type == "$_DFF_P_") dff_list.push_back(it.first); + if (it.second->type == "$_DFF_NN0_") dff_list.push_back(it.first); + if (it.second->type == "$_DFF_NN1_") dff_list.push_back(it.first); + if (it.second->type == "$_DFF_NP0_") dff_list.push_back(it.first); + if (it.second->type == "$_DFF_NP1_") dff_list.push_back(it.first); + if (it.second->type == "$_DFF_PN0_") dff_list.push_back(it.first); + if (it.second->type == "$_DFF_PN1_") dff_list.push_back(it.first); + if (it.second->type == "$_DFF_PP0_") dff_list.push_back(it.first); + if (it.second->type == "$_DFF_PP1_") dff_list.push_back(it.first); + if (it.second->type == "$dff") dff_list.push_back(it.first); + if (it.second->type == "$adff") dff_list.push_back(it.first); + } + + for (auto &id : dff_list) { + if (mod_it.second->cells.count(id) > 0 && + handle_dff(mod_it.second, mod_it.second->cells[id])) + total_count++; + } + } + + assign_map.clear(); + log("Replaced %d DFF cells.\n", total_count); + } +} OptRmdffPass; + |