From 66bc46b30b13ce6f9005edff7a479e28f223a678 Mon Sep 17 00:00:00 2001 From: Clifford Wolf Date: Fri, 24 May 2013 14:39:19 +0200 Subject: [PATCH] Improved FSM one-hot encoding, added binary encoding --- passes/fsm/fsm.cc | 8 ++++- passes/fsm/fsm_map.cc | 56 +++++++++++++++++++--------------- passes/fsm/fsm_recode.cc | 65 ++++++++++++++++++++++++++++------------ 3 files changed, 85 insertions(+), 44 deletions(-) diff --git a/passes/fsm/fsm.cc b/passes/fsm/fsm.cc index c0c42de9f..b4d7bc46f 100644 --- a/passes/fsm/fsm.cc +++ b/passes/fsm/fsm.cc @@ -56,6 +56,7 @@ struct FsmPass : public Pass { log(" -expand, -norecode, -export, -nomap\n"); log(" enable or disable passes as indicated above\n"); log("\n"); + log(" -encoding tye\n"); log(" -fm_set_fsm_file file\n"); log(" passed through to fsm_recode pass\n"); log("\n"); @@ -67,6 +68,7 @@ struct FsmPass : public Pass { bool flag_expand = false; bool flag_export = false; std::string fm_set_fsm_file_opt; + std::string encoding_opt; log_header("Executing FSM pass (extract and optimize FSM).\n"); log_push(); @@ -78,6 +80,10 @@ struct FsmPass : public Pass { fm_set_fsm_file_opt = " -fm_set_fsm_file " + args[++argidx]; continue; } + if (arg == "-encoding" && argidx+1 < args.size() && fm_set_fsm_file_opt.empty()) { + encoding_opt = " -encoding " + args[++argidx]; + continue; + } if (arg == "-norecode") { flag_norecode = true; continue; @@ -112,7 +118,7 @@ struct FsmPass : public Pass { } if (!flag_norecode) - Pass::call(design, "fsm_recode" + fm_set_fsm_file_opt); + Pass::call(design, "fsm_recode" + fm_set_fsm_file_opt + encoding_opt); Pass::call(design, "fsm_info"); if (!flag_nomap) diff --git a/passes/fsm/fsm_map.cc b/passes/fsm/fsm_map.cc index 063af587d..b8edf420a 100644 --- a/passes/fsm/fsm_map.cc +++ b/passes/fsm/fsm_map.cc @@ -77,27 +77,30 @@ static void implement_pattern_cache(RTLIL::Module *module, std::mapname = NEW_ID; - module->add(or_wire); - - RTLIL::Cell *or_cell = new RTLIL::Cell; - or_cell->name = NEW_ID; - or_cell->type = "$reduce_or"; - or_cell->connections["\\A"] = or_sig; - or_cell->connections["\\Y"] = RTLIL::SigSpec(or_wire); - or_cell->parameters["\\A_SIGNED"] = RTLIL::Const(false); - or_cell->parameters["\\A_WIDTH"] = RTLIL::Const(or_sig.width); - or_cell->parameters["\\Y_WIDTH"] = RTLIL::Const(1); - module->add(or_cell); - - and_sig.append(RTLIL::SigSpec(or_wire)); + if (or_sig.width == 1) + { + and_sig.append(or_sig); + } + else + { + RTLIL::Wire *or_wire = new RTLIL::Wire; + or_wire->name = NEW_ID; + module->add(or_wire); + + RTLIL::Cell *or_cell = new RTLIL::Cell; + or_cell->name = NEW_ID; + or_cell->type = "$reduce_or"; + or_cell->connections["\\A"] = or_sig; + or_cell->connections["\\Y"] = RTLIL::SigSpec(or_wire); + or_cell->parameters["\\A_SIGNED"] = RTLIL::Const(false); + or_cell->parameters["\\A_WIDTH"] = RTLIL::Const(or_sig.width); + or_cell->parameters["\\Y_WIDTH"] = RTLIL::Const(1); + module->add(or_cell); + + and_sig.append(RTLIL::SigSpec(or_wire)); + } } switch (and_sig.width) @@ -131,7 +134,7 @@ static void implement_pattern_cache(RTLIL::Module *module, std::maptype = "$adff"; state_dff->parameters["\\ARST_POLARITY"] = fsm_cell->parameters["\\ARST_POLARITY"]; state_dff->parameters["\\ARST_VALUE"] = fsm_data.state_table[fsm_data.reset_state]; + for (auto &bit : state_dff->parameters["\\ARST_VALUE"].bits) + if (bit != RTLIL::State::S1) + bit = RTLIL::State::S0; state_dff->connections["\\ARST"] = fsm_cell->connections["\\ARST"]; } state_dff->parameters["\\WIDTH"] = RTLIL::Const(fsm_data.state_bits); @@ -221,8 +227,7 @@ static void map_fsm(RTLIL::Cell *fsm_cell, RTLIL::Module *module) } else { - if (sig_b.as_bool() || sig_b.width != fsm_data.state_bits) - encoding_is_onehot = false; + encoding_is_onehot = false; RTLIL::Cell *eq_cell = new RTLIL::Cell; eq_cell->name = NEW_ID; @@ -266,6 +271,7 @@ static void map_fsm(RTLIL::Cell *fsm_cell, RTLIL::Module *module) if (encoding_is_onehot) { + RTLIL::SigSpec next_state_sig(RTLIL::State::Sm, next_state_wire->width); for (size_t i = 0; i < fsm_data.state_table.size(); i++) { RTLIL::Const state = fsm_data.state_table[i]; int bit_idx = -1; @@ -273,8 +279,10 @@ static void map_fsm(RTLIL::Cell *fsm_cell, RTLIL::Module *module) if (state.bits[j] == RTLIL::State::S1) bit_idx = j; if (bit_idx >= 0) - module->connections.push_back(RTLIL::SigSig(RTLIL::SigSpec(next_state_wire, 1, bit_idx), RTLIL::SigSpec(next_state_onehot, 1, i))); + next_state_sig.replace(bit_idx, RTLIL::SigSpec(next_state_onehot, 1, i)); } + log_assert(!next_state_sig.has_marked_bits()); + module->connections.push_back(RTLIL::SigSig(next_state_wire, next_state_sig)); } else { diff --git a/passes/fsm/fsm_recode.cc b/passes/fsm/fsm_recode.cc index acb5944a1..99ee0eb53 100644 --- a/passes/fsm/fsm_recode.cc +++ b/passes/fsm/fsm_recode.cc @@ -23,6 +23,7 @@ #include "kernel/consteval.h" #include "kernel/celltypes.h" #include "fsmdata.h" +#include "math.h" #include static void fm_set_fsm_print(RTLIL::Cell *cell, RTLIL::Module *module, FsmData &fsm_data, const char *prefix, FILE *f) @@ -46,31 +47,50 @@ static void fm_set_fsm_print(RTLIL::Cell *cell, RTLIL::Module *module, FsmData & prefix, RTLIL::unescape_id(module->name).c_str()); } -static void fsm_recode(RTLIL::Cell *cell, RTLIL::Module *module, FILE *fm_set_fsm_file) +static void fsm_recode(RTLIL::Cell *cell, RTLIL::Module *module, FILE *fm_set_fsm_file, std::string default_encoding) { + std::string encoding = cell->attributes.count("\\fsm_encoding") ? cell->attributes.at("\\fsm_encoding").str : "auto"; + + log("Recoding FSM `%s' from module `%s' using `%s' encoding:\n", cell->name.c_str(), module->name.c_str(), encoding.c_str()); + if (encoding != "none" && encoding != "one-hot" && encoding != "binary") { + if (encoding != "auto") + log(" unkown encoding `%s': using auto (%s) instead.\n", encoding.c_str(), default_encoding.c_str()); + encoding = default_encoding; + } + + if (encoding == "none") { + log(" nothing to do for encoding `none'.\n"); + return; + } + FsmData fsm_data; fsm_data.copy_from_cell(cell); - log("Recoding FSM `%s' from module `%s':\n", cell->name.c_str(), module->name.c_str()); - if (fm_set_fsm_file != NULL) fm_set_fsm_print(cell, module, fsm_data, "r", fm_set_fsm_file); - fsm_data.state_bits = fsm_data.state_table.size(); - if (fsm_data.reset_state >= 0) - fsm_data.state_bits--; - - int bit_pos = 0; - for (size_t i = 0; i < fsm_data.state_table.size(); i++) + if (encoding == "one-hot") { + fsm_data.state_bits = fsm_data.state_table.size(); + } else + if (encoding == "auto" || encoding == "binary") { + fsm_data.state_bits = ceil(log2(fsm_data.state_table.size())); + } else + log_error("FSM encoding `%s' is not supported!\n", encoding.c_str()); + + int state_idx_counter = fsm_data.reset_state >= 0 ? 1 : 0; + for (int i = 0; i < int(fsm_data.state_table.size()); i++) { + int state_idx = fsm_data.reset_state == i ? 0 : state_idx_counter++; RTLIL::Const new_code; - if (int(i) == fsm_data.reset_state) - new_code = RTLIL::Const(RTLIL::State::S0, fsm_data.state_bits); - else { - RTLIL::Const state_code(RTLIL::State::Sa, fsm_data.state_bits); - state_code.bits[bit_pos++] = RTLIL::State::S1; - new_code = state_code; - } + + if (encoding == "one-hot") { + new_code = RTLIL::Const(RTLIL::State::Sa, fsm_data.state_bits); + new_code.bits[state_idx] = RTLIL::State::S1; + } else + if (encoding == "auto" || encoding == "binary") { + new_code = RTLIL::Const(state_idx, fsm_data.state_bits); + } else + log_abort(); log(" %s -> %s\n", fsm_data.state_table[i].as_string().c_str(), new_code.as_string().c_str()); fsm_data.state_table[i] = new_code; @@ -88,10 +108,12 @@ struct FsmRecodePass : public Pass { { // |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---| log("\n"); - log(" fsm_recode [-fm_set_fsm_file file] [selection]\n"); + log(" fsm_recode [-encoding type] [-fm_set_fsm_file file] [selection]\n"); log("\n"); log("This pass reassign the state encodings for FSM cells. At the moment only\n"); - log("one-hot encoding is supported.\n"); + log("one-hot encoding and binary encoding is supported. The option -encoding\n"); + log("can be used to specify the encoding scheme used for FSMs without the\n"); + log("`fsm_encoding' attribute (or with the attribute set to `auto'.\n"); log("\n"); log("The option -fm_set_fsm_file can be used to generate a file containing the\n"); log("mapping from old to new FSM encoding in form of Synopsys Formality set_fsm_*\n"); @@ -101,6 +123,7 @@ struct FsmRecodePass : public Pass { virtual void execute(std::vector args, RTLIL::Design *design) { FILE *fm_set_fsm_file = NULL; + std::string default_encoding = "one-hot"; log_header("Executing FSM_RECODE pass (re-assigning FSM state encoding).\n"); size_t argidx; @@ -112,6 +135,10 @@ struct FsmRecodePass : public Pass { log_error("Can't open fm_set_fsm_file `%s' for writing: %s\n", args[argidx].c_str(), strerror(errno)); continue; } + if (arg == "-encoding" && argidx+1 < args.size() && fm_set_fsm_file == NULL) { + default_encoding = args[++argidx]; + continue; + } break; } extra_args(args, argidx, design); @@ -120,7 +147,7 @@ struct FsmRecodePass : public Pass { if (design->selected(mod_it.second)) for (auto &cell_it : mod_it.second->cells) if (cell_it.second->type == "$fsm" && design->selected(mod_it.second, cell_it.second)) - fsm_recode(cell_it.second, mod_it.second, fm_set_fsm_file); + fsm_recode(cell_it.second, mod_it.second, fm_set_fsm_file, default_encoding); if (fm_set_fsm_file != NULL) fclose(fm_set_fsm_file); -- 2.30.2