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yosys/passes/techmap/extract_fa.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 "kernel/consteval.h"
USING_YOSYS_NAMESPACE
PRIVATE_NAMESPACE_BEGIN
struct ExtractFaConfig
{
bool enable_fa = false;
bool enable_ha = false;
bool verbose = false;
int maxdepth = 20;
int maxbreadth = 6;
};
// http://svn.clifford.at/handicraft/2016/bindec/bindec.c
int bindec(unsigned char v)
{
int r = v & 1;
r += (~((v & 2) - 1)) & 10;
r += (~((v & 4) - 1)) & 100;
r += (~((v & 8) - 1)) & 1000;
r += (~((v & 16) - 1)) & 10000;
r += (~((v & 32) - 1)) & 100000;
r += (~((v & 64) - 1)) & 1000000;
r += (~((v & 128) - 1)) & 10000000;
return r;
}
struct ExtractFaWorker
{
const ExtractFaConfig &config;
Module *module;
ConstEval ce;
SigMap &sigmap;
dict<SigBit, Cell*> driver;
pool<SigBit> handled_bits;
const int xor2_func = 0x6, xnor2_func = 0x9;
const int xor3_func = 0x96, xnor3_func = 0x69;
pool<tuple<SigBit, SigBit>> xorxnor2;
pool<tuple<SigBit, SigBit, SigBit>> xorxnor3;
dict<tuple<SigBit, SigBit>, dict<int, pool<SigBit>>> func2;
dict<tuple<SigBit, SigBit, SigBit>, dict<int, pool<SigBit>>> func3;
int count_func2;
int count_func3;
struct func2_and_info_t {
bool inv_a, inv_b, inv_y;
};
struct func3_maj_info_t {
bool inv_a, inv_b, inv_c, inv_y;
};
dict<int, func2_and_info_t> func2_and_info;
dict<int, func3_maj_info_t> func3_maj_info;
ExtractFaWorker(const ExtractFaConfig &config, Module *module) :
config(config), module(module), ce(module), sigmap(ce.assign_map)
{
for (auto cell : module->selected_cells())
{
if (cell->type.in( "$_BUF_", "$_NOT_", "$_AND_", "$_NAND_", "$_OR_", "$_NOR_",
"$_XOR_", "$_XNOR_", "$_ANDNOT_", "$_ORNOT_", "$_MUX_", "$_NMUX_",
"$_AOI3_", "$_OAI3_", "$_AOI4_", "$_OAI4_"))
{
SigBit y = sigmap(SigBit(cell->getPort("\\Y")));
log_assert(driver.count(y) == 0);
driver[y] = cell;
}
}
for (int ia = 0; ia < 2; ia++)
for (int ib = 0; ib < 2; ib++)
{
func2_and_info_t f2i;
f2i.inv_a = ia;
f2i.inv_b = ib;
f2i.inv_y = false;
int func = 0;
for (int i = 0; i < 4; i++)
{
bool a = (i & 1) ? !f2i.inv_a : f2i.inv_a;
bool b = (i & 2) ? !f2i.inv_b : f2i.inv_b;
if (a && b) func |= 1 << i;
}
log_assert(func2_and_info.count(func) == 0);
func2_and_info[func] = f2i;
f2i.inv_y = true;
func ^= 15;
log_assert(func2_and_info.count(func) == 0);
func2_and_info[func] = f2i;
}
for (int ia = 0; ia < 2; ia++)
for (int ib = 0; ib < 2; ib++)
for (int ic = 0; ic < 2; ic++)
{
func3_maj_info_t f3i;
f3i.inv_a = ia;
f3i.inv_b = ib;
f3i.inv_c = ic;
f3i.inv_y = false;
int func = 0;
for (int i = 0; i < 8; i++)
{
bool a = (i & 1) ? !f3i.inv_a : f3i.inv_a;
bool b = (i & 2) ? !f3i.inv_b : f3i.inv_b;
bool c = (i & 4) ? !f3i.inv_c : f3i.inv_c;
if ((a && b) || (a && c) || (b &&c)) func |= 1 << i;
}
log_assert(func3_maj_info.count(func) == 0);
func3_maj_info[func] = f3i;
// f3i.inv_y = true;
// func ^= 255;
// log_assert(func3_maj_info.count(func) == 0);
// func3_maj_info[func] = f3i;
}
}
void check_partition(SigBit root, pool<SigBit> &leaves)
{
if (config.enable_ha && GetSize(leaves) == 2)
{
leaves.sort();
SigBit A = SigSpec(leaves)[0];
SigBit B = SigSpec(leaves)[1];
int func = 0;
for (int i = 0; i < 4; i++)
{
bool a_value = (i & 1) != 0;
bool b_value = (i & 2) != 0;
ce.push();
ce.set(A, a_value ? State::S1 : State::S0);
ce.set(B, b_value ? State::S1 : State::S0);
SigSpec sig = root;
if (!ce.eval(sig)) {
ce.pop();
return;
}
if (sig == State::S1)
func |= 1 << i;
ce.pop();
}
// log("%04d %s %s -> %s\n", bindec(func), log_signal(A), log_signal(B), log_signal(root));
if (func == xor2_func || func == xnor2_func)
xorxnor2.insert(tuple<SigBit, SigBit>(A, B));
count_func2++;
func2[tuple<SigBit, SigBit>(A, B)][func].insert(root);
}
if (config.enable_fa && GetSize(leaves) == 3)
{
leaves.sort();
SigBit A = SigSpec(leaves)[0];
SigBit B = SigSpec(leaves)[1];
SigBit C = SigSpec(leaves)[2];
int func = 0;
for (int i = 0; i < 8; i++)
{
bool a_value = (i & 1) != 0;
bool b_value = (i & 2) != 0;
bool c_value = (i & 4) != 0;
ce.push();
ce.set(A, a_value ? State::S1 : State::S0);
ce.set(B, b_value ? State::S1 : State::S0);
ce.set(C, c_value ? State::S1 : State::S0);
SigSpec sig = root;
if (!ce.eval(sig)) {
ce.pop();
return;
}
if (sig == State::S1)
func |= 1 << i;
ce.pop();
}
// log("%08d %s %s %s -> %s\n", bindec(func), log_signal(A), log_signal(B), log_signal(C), log_signal(root));
if (func == xor3_func || func == xnor3_func)
xorxnor3.insert(tuple<SigBit, SigBit, SigBit>(A, B, C));
count_func3++;
func3[tuple<SigBit, SigBit, SigBit>(A, B, C)][func].insert(root);
}
}
void find_partitions(SigBit root, pool<SigBit> &leaves, pool<pool<SigBit>> &cache, int maxdepth, int maxbreadth)
{
if (cache.count(leaves))
return;
// log("%*s[%d] %s:", 20-maxdepth, "", maxdepth, log_signal(root));
// for (auto bit : leaves)
// log(" %s", log_signal(bit));
// log("\n");
cache.insert(leaves);
check_partition(root, leaves);
if (maxdepth == 0)
return;
for (SigBit bit : leaves)
{
if (driver.count(bit) == 0)
continue;
Cell *cell = driver.at(bit);
pool<SigBit> new_leaves = leaves;
new_leaves.erase(bit);
if (cell->hasPort("\\A")) new_leaves.insert(sigmap(SigBit(cell->getPort("\\A"))));
if (cell->hasPort("\\B")) new_leaves.insert(sigmap(SigBit(cell->getPort("\\B"))));
if (cell->hasPort("\\C")) new_leaves.insert(sigmap(SigBit(cell->getPort("\\C"))));
if (cell->hasPort("\\D")) new_leaves.insert(sigmap(SigBit(cell->getPort("\\D"))));
if (GetSize(new_leaves) > maxbreadth)
continue;
find_partitions(root, new_leaves, cache, maxdepth-1, maxbreadth);
}
}
void assign_new_driver(SigBit bit, SigBit new_driver)
{
Cell *cell = driver.at(bit);
if (sigmap(cell->getPort("\\Y")) == bit) {
cell->setPort("\\Y", module->addWire(NEW_ID));
module->connect(bit, new_driver);
}
}
void run()
{
log("Extracting full/half adders from %s:\n", log_id(module));
for (auto it : driver)
{
if (it.second->type.in("$_BUF_", "$_NOT_"))
continue;
SigBit root = it.first;
pool<SigBit> leaves = { root };
pool<pool<SigBit>> cache;
if (config.verbose)
log(" checking %s\n", log_signal(it.first));
count_func2 = 0;
count_func3 = 0;
find_partitions(root, leaves, cache, config.maxdepth, config.maxbreadth);
if (config.verbose && count_func2 > 0)
log(" extracted %d two-input functions\n", count_func2);
if (config.verbose && count_func3 > 0)
log(" extracted %d three-input functions\n", count_func3);
}
for (auto &key : xorxnor3)
{
SigBit A = get<0>(key);
SigBit B = get<1>(key);
SigBit C = get<2>(key);
log(" 3-Input XOR/XNOR %s %s %s:\n", log_signal(A), log_signal(B), log_signal(C));
for (auto &it : func3.at(key))
{
if (it.first != xor3_func && it.first != xnor3_func)
continue;
log(" %08d ->", bindec(it.first));
for (auto bit : it.second)
log(" %s", log_signal(bit));
log("\n");
}
dict<int, tuple<SigBit, SigBit, Cell*>> facache;
for (auto &it : func3_maj_info)
{
int func = it.first;
auto f3i = it.second;
if (func3.at(key).count(func) == 0)
continue;
if (func3.at(key).count(xor3_func) == 0 && func3.at(key).count(xnor3_func) != 0) {
f3i.inv_a = !f3i.inv_a;
f3i.inv_b = !f3i.inv_b;
f3i.inv_c = !f3i.inv_c;
f3i.inv_y = !f3i.inv_y;
}
if (!f3i.inv_a && !f3i.inv_b && !f3i.inv_c && !f3i.inv_y) {
log(" Majority without inversions:\n");
} else {
log(" Majority with inverted");
if (f3i.inv_a) log(" A");
if (f3i.inv_b) log(" B");
if (f3i.inv_c) log(" C");
if (f3i.inv_y) log(" Y");
log(":\n");
}
log(" %08d ->", bindec(func));
for (auto bit : func3.at(key).at(func))
log(" %s", log_signal(bit));
log("\n");
int fakey = 0;
if (f3i.inv_a) fakey |= 1;
if (f3i.inv_b) fakey |= 2;
if (f3i.inv_c) fakey |= 4;
int fakey_inv = fakey ^ 7;
bool invert_xy = false;
SigBit X, Y;
if (facache.count(fakey))
{
auto &fa = facache.at(fakey);
X = get<0>(fa);
Y = get<1>(fa);
log(" Reusing $fa cell %s.\n", log_id(get<2>(fa)));
}
else
if (facache.count(fakey_inv))
{
auto &fa = facache.at(fakey_inv);
invert_xy = true;
X = get<0>(fa);
Y = get<1>(fa);
log(" Reusing $fa cell %s.\n", log_id(get<2>(fa)));
}
else
{
Cell *cell = module->addCell(NEW_ID, "$fa");
cell->setParam("\\WIDTH", 1);
log(" Created $fa cell %s.\n", log_id(cell));
cell->setPort("\\A", f3i.inv_a ? module->NotGate(NEW_ID, A) : A);
cell->setPort("\\B", f3i.inv_b ? module->NotGate(NEW_ID, B) : B);
cell->setPort("\\C", f3i.inv_c ? module->NotGate(NEW_ID, C) : C);
X = module->addWire(NEW_ID);
Y = module->addWire(NEW_ID);
cell->setPort("\\X", X);
cell->setPort("\\Y", Y);
facache[fakey] = make_tuple(X, Y, cell);
}
if (func3.at(key).count(xor3_func)) {
SigBit YY = invert_xy ? module->NotGate(NEW_ID, Y) : Y;
for (auto bit : func3.at(key).at(xor3_func))
assign_new_driver(bit, YY);
}
if (func3.at(key).count(xnor3_func)) {
SigBit YY = invert_xy ? Y : module->NotGate(NEW_ID, Y);
for (auto bit : func3.at(key).at(xnor3_func))
assign_new_driver(bit, YY);
}
SigBit XX = invert_xy != f3i.inv_y ? module->NotGate(NEW_ID, X) : X;
for (auto bit : func3.at(key).at(func))
assign_new_driver(bit, XX);
}
}
for (auto &key : xorxnor2)
{
SigBit A = get<0>(key);
SigBit B = get<1>(key);
log(" 2-Input XOR/XNOR %s %s:\n", log_signal(A), log_signal(B));
for (auto &it : func2.at(key))
{
if (it.first != xor2_func && it.first != xnor2_func)
continue;
log(" %04d ->", bindec(it.first));
for (auto bit : it.second)
log(" %s", log_signal(bit));
log("\n");
}
dict<int, tuple<SigBit, SigBit, Cell*>> facache;
for (auto &it : func2_and_info)
{
int func = it.first;
auto &f2i = it.second;
if (func2.at(key).count(func) == 0)
continue;
if (!f2i.inv_a && !f2i.inv_b && !f2i.inv_y) {
log(" AND without inversions:\n");
} else {
log(" AND with inverted");
if (f2i.inv_a) log(" A");
if (f2i.inv_b) log(" B");
if (f2i.inv_y) log(" Y");
log(":\n");
}
log(" %04d ->", bindec(func));
for (auto bit : func2.at(key).at(func))
log(" %s", log_signal(bit));
log("\n");
int fakey = 0;
if (f2i.inv_a) fakey |= 1;
if (f2i.inv_b) fakey |= 2;
int fakey_inv = fakey ^ 3;
bool invert_xy = false;
SigBit X, Y;
if (facache.count(fakey))
{
auto &fa = facache.at(fakey);
X = get<0>(fa);
Y = get<1>(fa);
log(" Reusing $fa cell %s.\n", log_id(get<2>(fa)));
}
else
if (facache.count(fakey_inv))
{
auto &fa = facache.at(fakey_inv);
invert_xy = true;
X = get<0>(fa);
Y = get<1>(fa);
log(" Reusing $fa cell %s.\n", log_id(get<2>(fa)));
}
else
{
Cell *cell = module->addCell(NEW_ID, "$fa");
cell->setParam("\\WIDTH", 1);
log(" Created $fa cell %s.\n", log_id(cell));
cell->setPort("\\A", f2i.inv_a ? module->NotGate(NEW_ID, A) : A);
cell->setPort("\\B", f2i.inv_b ? module->NotGate(NEW_ID, B) : B);
cell->setPort("\\C", State::S0);
X = module->addWire(NEW_ID);
Y = module->addWire(NEW_ID);
cell->setPort("\\X", X);
cell->setPort("\\Y", Y);
}
if (func2.at(key).count(xor2_func)) {
SigBit YY = invert_xy ? module->NotGate(NEW_ID, Y) : Y;
for (auto bit : func2.at(key).at(xor2_func))
assign_new_driver(bit, YY);
}
if (func2.at(key).count(xnor2_func)) {
SigBit YY = invert_xy ? Y : module->NotGate(NEW_ID, Y);
for (auto bit : func2.at(key).at(xnor2_func))
assign_new_driver(bit, YY);
}
SigBit XX = invert_xy != f2i.inv_y ? module->NotGate(NEW_ID, X) : X;
for (auto bit : func2.at(key).at(func))
assign_new_driver(bit, XX);
}
}
}
};
struct ExtractFaPass : public Pass {
ExtractFaPass() : Pass("extract_fa", "find and extract full/half adders") { }
void help() YS_OVERRIDE
{
// |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
log("\n");
log(" extract_fa [options] [selection]\n");
log("\n");
log("This pass extracts full/half adders from a gate-level design.\n");
log("\n");
log(" -fa, -ha\n");
log(" Enable cell types (fa=full adder, ha=half adder)\n");
log(" All types are enabled if none of this options is used\n");
log("\n");
log(" -d <int>\n");
log(" Set maximum depth for extracted logic cones (default=20)\n");
log("\n");
log(" -b <int>\n");
log(" Set maximum breadth for extracted logic cones (default=6)\n");
log("\n");
log(" -v\n");
log(" Verbose output\n");
log("\n");
}
void execute(std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
{
ExtractFaConfig config;
log_header(design, "Executing EXTRACT_FA pass (find and extract full/half adders).\n");
log_push();
size_t argidx;
for (argidx = 1; argidx < args.size(); argidx++)
{
if (args[argidx] == "-fa") {
config.enable_fa = true;
continue;
}
if (args[argidx] == "-ha") {
config.enable_ha = true;
continue;
}
if (args[argidx] == "-v") {
config.verbose = true;
continue;
}
if (args[argidx] == "-d" && argidx+2 < args.size()) {
config.maxdepth = std::stoi(args[++argidx]);
continue;
}
if (args[argidx] == "-b" && argidx+2 < args.size()) {
config.maxbreadth = std::stoi(args[++argidx]);
continue;
}
break;
}
extra_args(args, argidx, design);
if (!config.enable_fa && !config.enable_ha) {
config.enable_fa = true;
config.enable_ha = true;
}
for (auto module : design->selected_modules())
{
ExtractFaWorker worker(config, module);
worker.run();
}
log_pop();
}
} ExtractFaPass;
PRIVATE_NAMESPACE_END
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