yosys/passes/techmap/pmuxtree.cc

113 lines
3.4 KiB
C++

/*
* 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"
USING_YOSYS_NAMESPACE
PRIVATE_NAMESPACE_BEGIN
static SigSpec or_generator(Module *module, const SigSpec &sig)
{
switch (GetSize(sig))
{
case 0:
return State::S0;
case 1:
return sig;
case 2:
return module->Or(NEW_ID, sig[0], sig[1]);
default:
return module->ReduceOr(NEW_ID, sig);
}
}
static SigSpec recursive_mux_generator(Module *module, const SigSpec &sig_data, const SigSpec &sig_sel, SigSpec &sig_or)
{
if (GetSize(sig_sel) == 1) {
sig_or.append(sig_sel);
return sig_data;
}
int left_size = GetSize(sig_sel) / 2;
int right_size = GetSize(sig_sel) - left_size;
int stride = GetSize(sig_data) / GetSize(sig_sel);
SigSpec left_data = sig_data.extract(0, stride*left_size);
SigSpec right_data = sig_data.extract(stride*left_size, stride*right_size);
SigSpec left_sel = sig_sel.extract(0, left_size);
SigSpec right_sel = sig_sel.extract(left_size, right_size);
SigSpec left_or, left_result, right_result;
left_result = recursive_mux_generator(module, left_data, left_sel, left_or);
right_result = recursive_mux_generator(module, right_data, right_sel, sig_or);
left_or = or_generator(module, left_or);
sig_or.append(left_or);
return module->Mux(NEW_ID, right_result, left_result, left_or);
}
struct PmuxtreePass : public Pass {
PmuxtreePass() : Pass("pmuxtree", "transform $pmux cells to trees of $mux cells") { }
void help() override
{
// |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
log("\n");
log(" pmuxtree [selection]\n");
log("\n");
log("This pass transforms $pmux cells to trees of $mux cells.\n");
log("\n");
}
void execute(std::vector<std::string> args, RTLIL::Design *design) override
{
log_header(design, "Executing PMUXTREE pass.\n");
size_t argidx;
for (argidx = 1; argidx < args.size(); argidx++) {
break;
}
extra_args(args, argidx, design);
for (auto module : design->selected_modules())
for (auto cell : module->selected_cells())
{
if (cell->type != ID($pmux))
continue;
SigSpec sig_data = cell->getPort(ID::B);
SigSpec sig_sel = cell->getPort(ID::S);
if (!cell->getPort(ID::A).is_fully_undef()) {
sig_data.append(cell->getPort(ID::A));
SigSpec sig_sel_or = module->ReduceOr(NEW_ID, sig_sel);
sig_sel.append(module->Not(NEW_ID, sig_sel_or));
}
SigSpec result, result_or;
result = recursive_mux_generator(module, sig_data, sig_sel, result_or);
module->connect(cell->getPort(ID::Y), result);
module->remove(cell);
}
}
} PmuxtreePass;
PRIVATE_NAMESPACE_END