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yosys/passes/sat/async2sync.cc
Marcelina Kościelnicka 4e70c30775 FfData: some refactoring. 
- FfData now keeps track of the module and underlying cell, if any (so
  calling emit on FfData created from a cell will replace the existing cell)
- FfData implementation is split off to its own .cc file for faster
  compilation
- the "flip FF data sense by inserting inverters in front and after"
  functionality that zinit uses is moved onto FfData class and beefed up
  to have dffsr support, to support more use cases
2021-10-07 04:24:06 +02:00

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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/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") { }
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");
}
void execute(std::vector<std::string> args, RTLIL::Design *design) override
{
// bool flag_noinit = false;
log_header(design, "Executing ASYNC2SYNC pass.\n");
size_t argidx;
for (argidx = 1; argidx < args.size(); argidx++)
{
// if (args[argidx] == "-noinit") {
// flag_noinit = true;
// continue;
// }
break;
}
extra_args(args, argidx, design);
for (auto module : design->selected_modules())
{
SigMap sigmap(module);
FfInitVals initvals(&sigmap, module);
for (auto cell : vector<Cell*>(module->selected_cells()))
{
if (!RTLIL::builtin_ff_cell_types().count(cell->type))
continue;
FfData ff(&initvals, cell);
// Skip for $_FF_ and $ff cells.
if (ff.has_gclk)
continue;
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();
}
}
}
} Async2syncPass;
PRIVATE_NAMESPACE_END
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