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yosys/techlibs/ice40/ice40_opt.cc

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/*
* yosys -- Yosys Open SYnthesis Suite
*
* Copyright (C) 2012 Clifford Wolf <clifford@clifford.at>
*
* 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 "passes/techmap/simplemap.h"
#include <stdlib.h>
#include <stdio.h>
USING_YOSYS_NAMESPACE
PRIVATE_NAMESPACE_BEGIN
static SigBit get_bit_or_zero(const SigSpec &sig)
{
if (GetSize(sig) == 0)
return State::S0;
return sig[0];
}
static void run_ice40_opts(Module *module)
{
pool<SigBit> optimized_co;
vector<Cell*> sb_lut_cells;
SigMap sigmap(module);
for (auto cell : module->selected_cells())
{
if (!cell->type.in("\\SB_LUT4", "\\SB_CARRY", "$__ICE40_CARRY_WRAPPER"))
continue;
if (cell->has_keep_attr())
continue;
if (cell->type == "\\SB_LUT4")
{
sb_lut_cells.push_back(cell);
continue;
}
if (cell->type == "\\SB_CARRY")
{
SigSpec non_const_inputs, replacement_output;
int count_zeros = 0, count_ones = 0;
SigBit inbit[3] = {
get_bit_or_zero(cell->getPort("\\I0")),
get_bit_or_zero(cell->getPort("\\I1")),
get_bit_or_zero(cell->getPort("\\CI"))
};
for (int i = 0; i < 3; i++)
if (inbit[i].wire == nullptr) {
if (inbit[i] == State::S1)
count_ones++;
else
count_zeros++;
} else
non_const_inputs.append(inbit[i]);
if (count_zeros >= 2)
replacement_output = State::S0;
else if (count_ones >= 2)
replacement_output = State::S1;
else if (GetSize(non_const_inputs) == 1)
replacement_output = non_const_inputs;
if (GetSize(replacement_output)) {
optimized_co.insert(sigmap(cell->getPort("\\CO")[0]));
module->connect(cell->getPort("\\CO")[0], replacement_output);
module->design->scratchpad_set_bool("opt.did_something", true);
log("Optimized away SB_CARRY cell %s.%s: CO=%s\n",
log_id(module), log_id(cell), log_signal(replacement_output));
module->remove(cell);
}
continue;
}
if (cell->type == "$__ICE40_CARRY_WRAPPER")
{
SigSpec non_const_inputs, replacement_output;
int count_zeros = 0, count_ones = 0;
SigBit inbit[3] = {
cell->getPort("\\A"),
cell->getPort("\\B"),
cell->getPort("\\CI")
};
for (int i = 0; i < 3; i++)
if (inbit[i].wire == nullptr) {
if (inbit[i] == State::S1)
count_ones++;
else
count_zeros++;
} else
non_const_inputs.append(inbit[i]);
if (count_zeros >= 2)
replacement_output = State::S0;
else if (count_ones >= 2)
replacement_output = State::S1;
else if (GetSize(non_const_inputs) == 1)
replacement_output = non_const_inputs;
if (GetSize(replacement_output)) {
optimized_co.insert(sigmap(cell->getPort("\\CO")[0]));
auto it = cell->attributes.find(ID(SB_LUT4.name));
if (it != cell->attributes.end()) {
module->rename(cell, it->second.decode_string());
decltype(Cell::attributes) new_attr;
for (const auto &a : cell->attributes)
if (a.first.begins_with("\\SB_LUT4.\\"))
new_attr[a.first.c_str() + strlen("\\SB_LUT4.")] = a.second;
else if (a.first == ID(src))
new_attr.insert(std::make_pair(a.first, a.second));
else if (a.first.in(ID(SB_LUT4.name), ID::keep, ID(module_not_derived)))
continue;
else if (a.first.begins_with("\\SB_CARRY.\\"))
continue;
else
log_abort();
cell->attributes = std::move(new_attr);
}
module->connect(cell->getPort("\\CO")[0], replacement_output);
module->design->scratchpad_set_bool("opt.did_something", true);
log("Optimized $__ICE40_CARRY_WRAPPER cell back to logic (without SB_CARRY) %s.%s: CO=%s\n",
log_id(module), log_id(cell), log_signal(replacement_output));
cell->type = "$lut";
auto I3 = get_bit_or_zero(cell->getPort(cell->getParam(ID(I3_IS_CI)).as_bool() ? ID(CI) : ID(I3)));
cell->setPort("\\A", { get_bit_or_zero(cell->getPort("\\I0")), inbit[0], inbit[1], I3 });
cell->setPort("\\Y", cell->getPort("\\O"));
cell->unsetPort("\\B");
cell->unsetPort("\\CI");
cell->unsetPort("\\I0");
cell->unsetPort("\\I3");
cell->unsetPort("\\CO");
cell->unsetPort("\\O");
cell->setParam("\\WIDTH", 4);
cell->unsetParam("\\I3_IS_CI");
}
continue;
}
}
for (auto cell : sb_lut_cells)
{
SigSpec inbits;
inbits.append(get_bit_or_zero(cell->getPort("\\I0")));
inbits.append(get_bit_or_zero(cell->getPort("\\I1")));
inbits.append(get_bit_or_zero(cell->getPort("\\I2")));
inbits.append(get_bit_or_zero(cell->getPort("\\I3")));
sigmap.apply(inbits);
if (optimized_co.count(inbits[0])) goto remap_lut;
if (optimized_co.count(inbits[1])) goto remap_lut;
if (optimized_co.count(inbits[2])) goto remap_lut;
if (optimized_co.count(inbits[3])) goto remap_lut;
if (!sigmap(inbits).is_fully_const())
continue;
remap_lut:
module->design->scratchpad_set_bool("opt.did_something", true);
log("Mapping SB_LUT4 cell %s.%s back to logic.\n", log_id(module), log_id(cell));
cell->type ="$lut";
cell->setParam("\\WIDTH", 4);
cell->setParam("\\LUT", cell->getParam("\\LUT_INIT"));
cell->unsetParam("\\LUT_INIT");
cell->setPort("\\A", SigSpec({
get_bit_or_zero(cell->getPort("\\I3")),
get_bit_or_zero(cell->getPort("\\I2")),
get_bit_or_zero(cell->getPort("\\I1")),
get_bit_or_zero(cell->getPort("\\I0"))
}));
cell->setPort("\\Y", cell->getPort("\\O")[0]);
cell->unsetPort("\\I0");
cell->unsetPort("\\I1");
cell->unsetPort("\\I2");
cell->unsetPort("\\I3");
cell->unsetPort("\\O");
cell->check();
simplemap_lut(module, cell);
module->remove(cell);
}
}
struct Ice40OptPass : public Pass {
Ice40OptPass() : Pass("ice40_opt", "iCE40: perform simple optimizations") { }
void help() YS_OVERRIDE
{
// |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
log("\n");
log(" ice40_opt [options] [selection]\n");
log("\n");
log("This command executes the following script:\n");
log("\n");
log(" do\n");
log(" <ice40 specific optimizations>\n");
log(" opt_expr -mux_undef -undriven [-full]\n");
log(" opt_merge\n");
log(" opt_rmdff\n");
log(" opt_clean\n");
log(" while <changed design>\n");
log("\n");
}
void execute(std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
{
string opt_expr_args = "-mux_undef -undriven";
log_header(design, "Executing ICE40_OPT pass (performing simple optimizations).\n");
log_push();
size_t argidx;
for (argidx = 1; argidx < args.size(); argidx++) {
if (args[argidx] == "-full") {
opt_expr_args += " -full";
continue;
}
break;
}
extra_args(args, argidx, design);
while (1)
{
design->scratchpad_unset("opt.did_something");
log_header(design, "Running ICE40 specific optimizations.\n");
for (auto module : design->selected_modules())
run_ice40_opts(module);
Pass::call(design, "opt_expr " + opt_expr_args);
Pass::call(design, "opt_merge");
Pass::call(design, "opt_rmdff");
Pass::call(design, "opt_clean");
if (design->scratchpad_get_bool("opt.did_something") == false)
break;
log_header(design, "Rerunning OPT passes. (Removed registers in this run.)\n");
}
design->optimize();
design->sort();
design->check();
log_header(design, "Finished OPT passes. (There is nothing left to do.)\n");
log_pop();
}
} Ice40OptPass;
PRIVATE_NAMESPACE_END
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