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Add dffunmap pass.

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To be used with backends that cannot deal with fancy FF types (like blif
or smt).
This commit is contained in:
Marcelina Kościelnicka 2020-07-27 15:24:57 +02:00
parent 6cd135a5eb
commit 18ad56ef41
3 changed files with 208 additions and 0 deletions
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passes/techmap/dffunmap.cc Normal file
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/*
* yosys -- Yosys Open SYnthesis Suite
*
* Copyright (C) 2020 Marcelina Kościelnicka <mwk@0x04.net>
*
* 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/ff.h"
USING_YOSYS_NAMESPACE
PRIVATE_NAMESPACE_BEGIN
struct DffunmapPass : public Pass {
DffunmapPass() : Pass("dffunmap", "unmap clock enable and synchronous reset from FFs") { }
void help() override
{
// |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
log("\n");
log(" dffunmap [options] [selection]\n");
log("\n");
log("This pass transforms FF types with clock enable and/or synchronous reset into\n");
log("their base type (with neither clock enable nor sync reset) by emulating the clock\n");
log("enable and synchronous reset with multiplexers on the cell input.\n");
log("\n");
log(" -ce-only\n");
log(" unmap only clock enables, leave synchronous resets alone.\n");
log("\n");
log(" -srst-only\n");
log(" unmap only synchronous resets, leave clock enables alone.\n");
log("\n");
}
void execute(std::vector<std::string> args, RTLIL::Design *design) override
{
log_header(design, "Executing DFFUNMAP pass (unmap clock enable and synchronous reset from FFs).\n");
bool ce_only = false;
bool srst_only = false;
size_t argidx;
for (argidx = 1; argidx < args.size(); argidx++) {
if (args[argidx] == "-ce-only") {
ce_only = true;
continue;
}
if (args[argidx] == "-srst-only") {
srst_only = true;
continue;
}
break;
}
extra_args(args, argidx, design);
if (ce_only && srst_only)
log_cmd_error("Options -ce-only and -srst-only are mutually exclusive!\n");
for (auto mod : design->selected_modules())
{
SigMap sigmap(mod);
FfInitVals initvals(&sigmap, mod);
for (auto cell : mod->selected_cells())
{
if (!RTLIL::builtin_ff_cell_types().count(cell->type))
continue;
FfData ff(&initvals, cell);
IdString name = cell->name;
if (!ff.has_clk)
continue;
if (ce_only) {
if (!ff.has_en)
continue;
ff.unmap_ce(mod);
} else if (srst_only) {
if (!ff.has_srst)
continue;
ff.unmap_srst(mod);
} else {
if (!ff.has_en && !ff.has_srst)
continue;
ff.unmap_ce_srst(mod);
}
mod->remove(cell);
ff.emit(mod, name);
}
}
}
} DffunmapPass;
PRIVATE_NAMESPACE_END