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yosys/passes/sat/async2sync.cc

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/*
* 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/log_help.h"
#include "kernel/sigtools.h"
#include "kernel/ffinit.h"
#include "kernel/ff.h"
USING_YOSYS_NAMESPACE
PRIVATE_NAMESPACE_BEGIN
struct Async2syncPass : public Pass {
Async2syncPass() : Pass("async2sync", "convert async FF inputs to sync circuits") { }
bool formatted_help() override {
auto *help = PrettyHelp::get_current();
help->set_group("formal");
return false;
}
void help() override
{
// |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
log("\n");
log(" async2sync [options] [selection]\n");
log("\n");
log("This command replaces async FF inputs with sync circuits emulating the same\n");
log("behavior for when the async signals are actually synchronized to the clock.\n");
log("\n");
log("This pass assumes negative hold time for the async FF inputs. For example when\n");
log("a reset deasserts with the clock edge, then the FF output will still drive the\n");
log("reset value in the next cycle regardless of the data-in value at the time of\n");
log("the clock edge.\n");
log("\n");
log(" -nolower\n");
log(" Do not automatically run 'chformal -lower' to lower $check cells.\n");
log("\n");
}
void execute(std::vector<std::string> args, RTLIL::Design *design) override
{
bool flag_nolower = false;
log_header(design, "Executing ASYNC2SYNC pass.\n");
size_t argidx;
for (argidx = 1; argidx < args.size(); argidx++)
{
if (args[argidx] == "-nolower") {
flag_nolower = true;
continue;
}
break;
}
extra_args(args, argidx, design);
bool have_check_cells = false;
for (auto module : design->selected_modules())
{
SigMap sigmap(module);
FfInitVals initvals(&sigmap, module);
SigBit initstate;
for (auto cell : vector<Cell*>(module->selected_cells()))
{
if (cell->type.in(ID($print), ID($check)))
{
if (cell->type == ID($check))
have_check_cells = true;
bool trg_enable = cell->getParam(ID(TRG_ENABLE)).as_bool();
if (!trg_enable)
continue;
int trg_width = cell->getParam(ID(TRG_WIDTH)).as_int();
if (trg_width > 1)
log_error("$check cell %s with TRG_WIDTH > 1 is not support by async2sync, use clk2fflogic.\n", log_id(cell));
if (trg_width == 0) {
if (initstate == State::S0)
initstate = module->Initstate(NEW_ID);
SigBit sig_en = cell->getPort(ID::EN);
cell->setPort(ID::EN, module->And(NEW_ID, sig_en, initstate));
} else {
SigBit sig_en = cell->getPort(ID::EN);
SigSpec sig_args = cell->getPort(ID::ARGS);
bool trg_polarity = cell->getParam(ID(TRG_POLARITY)).as_bool();
SigBit sig_trg = cell->getPort(ID::TRG);
Wire *sig_en_q = module->addWire(NEW_ID);
Wire *sig_args_q = module->addWire(NEW_ID, GetSize(sig_args));
sig_en_q->attributes.emplace(ID::init, State::S0);
module->addDff(NEW_ID, sig_trg, sig_en, sig_en_q, trg_polarity, cell->get_src_attribute());
module->addDff(NEW_ID, sig_trg, sig_args, sig_args_q, trg_polarity, cell->get_src_attribute());
cell->setPort(ID::EN, sig_en_q);
cell->setPort(ID::ARGS, sig_args_q);
if (cell->type == ID($check)) {
SigBit sig_a = cell->getPort(ID::A);
Wire *sig_a_q = module->addWire(NEW_ID);
sig_a_q->attributes.emplace(ID::init, State::S1);
module->addDff(NEW_ID, sig_trg, sig_a, sig_a_q, trg_polarity, cell->get_src_attribute());
cell->setPort(ID::A, sig_a_q);
}
}
cell->setPort(ID::TRG, SigSpec());
cell->setParam(ID::TRG_ENABLE, false);
cell->setParam(ID::TRG_WIDTH, 0);
cell->setParam(ID::TRG_POLARITY, false);
cell->set_bool_attribute(ID(trg_on_gclk));
continue;
}
if (!cell->is_builtin_ff())
continue;
FfData ff(&initvals, cell);
// Skip for $_FF_ and $ff cells.
if (ff.has_gclk)
continue;
if (ff.has_clk && ff.sig_clk.is_fully_const())
ff.has_ce = ff.has_clk = ff.has_srst = false;
if (ff.has_clk)
{
if (ff.has_sr) {
ff.unmap_ce_srst();
log("Replacing %s.%s (%s): SET=%s, CLR=%s, D=%s, Q=%s\n",
log_id(module), log_id(cell), log_id(cell->type),
log_signal(ff.sig_set), log_signal(ff.sig_clr), log_signal(ff.sig_d), log_signal(ff.sig_q));
initvals.remove_init(ff.sig_q);
Wire *new_d = module->addWire(NEW_ID, ff.width);
Wire *new_q = module->addWire(NEW_ID, ff.width);
SigSpec sig_set = ff.sig_set;
SigSpec sig_clr = ff.sig_clr;
if (!ff.pol_set) {
if (!ff.is_fine)
sig_set = module->Not(NEW_ID, sig_set);
else
sig_set = module->NotGate(NEW_ID, sig_set);
}
if (ff.pol_clr) {
if (!ff.is_fine)
sig_clr = module->Not(NEW_ID, sig_clr);
else
sig_clr = module->NotGate(NEW_ID, sig_clr);
}
if (!ff.is_fine) {
SigSpec tmp = module->Or(NEW_ID, ff.sig_d, sig_set);
module->addAnd(NEW_ID, tmp, sig_clr, new_d);
tmp = module->Or(NEW_ID, new_q, sig_set);
module->addAnd(NEW_ID, tmp, sig_clr, ff.sig_q);
} else {
SigSpec tmp = module->OrGate(NEW_ID, ff.sig_d, sig_set);
module->addAndGate(NEW_ID, tmp, sig_clr, new_d);
tmp = module->OrGate(NEW_ID, new_q, sig_set);
module->addAndGate(NEW_ID, tmp, sig_clr, ff.sig_q);
}
ff.sig_d = new_d;
ff.sig_q = new_q;
ff.has_sr = false;
} else if (ff.has_aload) {
ff.unmap_ce_srst();
log("Replacing %s.%s (%s): ALOAD=%s, AD=%s, D=%s, Q=%s\n",
log_id(module), log_id(cell), log_id(cell->type),
log_signal(ff.sig_aload), log_signal(ff.sig_ad), log_signal(ff.sig_d), log_signal(ff.sig_q));
initvals.remove_init(ff.sig_q);
Wire *new_d = module->addWire(NEW_ID, ff.width);
Wire *new_q = module->addWire(NEW_ID, ff.width);
if (ff.pol_aload) {
if (!ff.is_fine) {
module->addMux(NEW_ID, new_q, ff.sig_ad, ff.sig_aload, ff.sig_q);
module->addMux(NEW_ID, ff.sig_d, ff.sig_ad, ff.sig_aload, new_d);
} else {
module->addMuxGate(NEW_ID, new_q, ff.sig_ad, ff.sig_aload, ff.sig_q);
module->addMuxGate(NEW_ID, ff.sig_d, ff.sig_ad, ff.sig_aload, new_d);
}
} else {
if (!ff.is_fine) {
module->addMux(NEW_ID, ff.sig_ad, new_q, ff.sig_aload, ff.sig_q);
module->addMux(NEW_ID, ff.sig_ad, ff.sig_d, ff.sig_aload, new_d);
} else {
module->addMuxGate(NEW_ID, ff.sig_ad, new_q, ff.sig_aload, ff.sig_q);
module->addMuxGate(NEW_ID, ff.sig_ad, ff.sig_d, ff.sig_aload, new_d);
}
}
ff.sig_d = new_d;
ff.sig_q = new_q;
ff.has_aload = false;
} else if (ff.has_arst) {
ff.unmap_srst();
log("Replacing %s.%s (%s): ARST=%s, D=%s, Q=%s\n",
log_id(module), log_id(cell), log_id(cell->type),
log_signal(ff.sig_arst), log_signal(ff.sig_d), log_signal(ff.sig_q));
initvals.remove_init(ff.sig_q);
Wire *new_q = module->addWire(NEW_ID, ff.width);
if (ff.pol_arst) {
if (!ff.is_fine)
module->addMux(NEW_ID, new_q, ff.val_arst, ff.sig_arst, ff.sig_q);
else
module->addMuxGate(NEW_ID, new_q, ff.val_arst[0], ff.sig_arst, ff.sig_q);
} else {
if (!ff.is_fine)
module->addMux(NEW_ID, ff.val_arst, new_q, ff.sig_arst, ff.sig_q);
else
module->addMuxGate(NEW_ID, ff.val_arst[0], new_q, ff.sig_arst, ff.sig_q);
}
ff.sig_q = new_q;
ff.has_arst = false;
ff.has_srst = true;
ff.ce_over_srst = false;
ff.val_srst = ff.val_arst;
ff.sig_srst = ff.sig_arst;
ff.pol_srst = ff.pol_arst;
} else {
continue;
}
}
else
{
// Latch.
log("Replacing %s.%s (%s): EN=%s, D=%s, Q=%s\n",
log_id(module), log_id(cell), log_id(cell->type),
log_signal(ff.sig_aload), log_signal(ff.sig_ad), log_signal(ff.sig_q));
initvals.remove_init(ff.sig_q);
Wire *new_q = module->addWire(NEW_ID, ff.width);
Wire *new_d;
if (ff.has_aload) {
new_d = module->addWire(NEW_ID, ff.width);
if (ff.pol_aload) {
if (!ff.is_fine)
module->addMux(NEW_ID, new_q, ff.sig_ad, ff.sig_aload, new_d);
else
module->addMuxGate(NEW_ID, new_q, ff.sig_ad, ff.sig_aload, new_d);
} else {
if (!ff.is_fine)
module->addMux(NEW_ID, ff.sig_ad, new_q, ff.sig_aload, new_d);
else
module->addMuxGate(NEW_ID, ff.sig_ad, new_q, ff.sig_aload, new_d);
}
} else {
new_d = new_q;
}
if (ff.has_sr) {
SigSpec sig_set = ff.sig_set;
SigSpec sig_clr = ff.sig_clr;
if (!ff.pol_set) {
if (!ff.is_fine)
sig_set = module->Not(NEW_ID, sig_set);
else
sig_set = module->NotGate(NEW_ID, sig_set);
}
if (ff.pol_clr) {
if (!ff.is_fine)
sig_clr = module->Not(NEW_ID, sig_clr);
else
sig_clr = module->NotGate(NEW_ID, sig_clr);
}
if (!ff.is_fine) {
SigSpec tmp = module->Or(NEW_ID, new_d, sig_set);
module->addAnd(NEW_ID, tmp, sig_clr, ff.sig_q);
} else {
SigSpec tmp = module->OrGate(NEW_ID, new_d, sig_set);
module->addAndGate(NEW_ID, tmp, sig_clr, ff.sig_q);
}
} else if (ff.has_arst) {
if (ff.pol_arst) {
if (!ff.is_fine)
module->addMux(NEW_ID, new_d, ff.val_arst, ff.sig_arst, ff.sig_q);
else
module->addMuxGate(NEW_ID, new_d, ff.val_arst[0], ff.sig_arst, ff.sig_q);
} else {
if (!ff.is_fine)
module->addMux(NEW_ID, ff.val_arst, new_d, ff.sig_arst, ff.sig_q);
else
module->addMuxGate(NEW_ID, ff.val_arst[0], new_d, ff.sig_arst, ff.sig_q);
}
} else {
module->connect(ff.sig_q, new_d);
}
ff.sig_d = new_d;
ff.sig_q = new_q;
ff.has_aload = false;
ff.has_arst = false;
ff.has_sr = false;
ff.has_gclk = true;
}
ff.emit();
}
}
if (have_check_cells && !flag_nolower) {
log_push();
Pass::call(design, "chformal -lower");
log_pop();
}
}
} Async2syncPass;
PRIVATE_NAMESPACE_END
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