yosys/passes/memory/memory_bmux2rom.cc

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2022-05-18 14:20:42 -05:00
/*
* yosys -- Yosys Open SYnthesis Suite
*
* Copyright (C) 2022 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/mem.h"
USING_YOSYS_NAMESPACE
PRIVATE_NAMESPACE_BEGIN
struct MemoryBmux2RomPass : public Pass {
MemoryBmux2RomPass() : Pass("memory_bmux2rom", "convert muxes to ROMs") { }
void help() override
{
// |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
log("\n");
log(" memory_bmux2rom [options] [selection]\n");
log("\n");
log("This pass converts $bmux cells with constant A input to ROMs.\n");
log("\n");
}
void execute(std::vector<std::string> args, RTLIL::Design *design) override
{
log_header(design, "Executing MEMORY_BMUX2ROM pass (converting muxes to ROMs).\n");
size_t argidx;
for (argidx = 1; argidx < args.size(); argidx++) {
break;
}
extra_args(args, argidx, design);
for (auto module : design->selected_modules()) {
for (auto cell : module->selected_cells()) {
if (cell->type != ID($bmux))
continue;
SigSpec sig_a = cell->getPort(ID::A);
if (!sig_a.is_fully_const())
continue;
int abits = cell->getParam(ID::S_WIDTH).as_int();
int width = cell->getParam(ID::WIDTH).as_int();
if (abits < 3)
continue;
// Ok, let's do it.
Mem mem(module, NEW_ID, width, 0, 1 << abits);
mem.attributes = cell->attributes;
MemInit init;
init.addr = 0;
init.data = sig_a.as_const();
init.en = Const(State::S1, width);
mem.inits.push_back(std::move(init));
MemRd rd;
rd.addr = cell->getPort(ID::S);
rd.data = cell->getPort(ID::Y);
rd.init_value = Const(State::Sx, width);
rd.arst_value = Const(State::Sx, width);
rd.srst_value = Const(State::Sx, width);
mem.rd_ports.push_back(std::move(rd));
mem.emit();
module->remove(cell);
}
}
}
} MemoryBmux2RomPass;
PRIVATE_NAMESPACE_END