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Remove old place legaliser, set placement constraints instead (currently ignored by placer)

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Signed-off-by: David Shah <davey1576@gmail.com>
This commit is contained in:
David Shah 2018-08-03 10:31:03 +02:00
parent 80e6b17ec9
commit 26c68c4bcc
10 changed files with 288 additions and 679 deletions
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4
common/placer1.cc
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@ -38,7 +38,6 @@
#include <vector> #include <vector>
#include "log.h" #include "log.h"
#include "place_common.h" #include "place_common.h"
#include "place_legaliser.h"
#include "timing.h" #include "timing.h"
#include "util.h" #include "util.h"
NEXTPNR_NAMESPACE_BEGIN NEXTPNR_NAMESPACE_BEGIN
@ -225,7 +224,8 @@ class SAPlacer
// Once cooled below legalise threshold, run legalisation and start requiring // Once cooled below legalise threshold, run legalisation and start requiring
// legal moves only // legal moves only
if (temp < legalise_temp && !require_legal) { if (temp < legalise_temp && !require_legal) {
legalise_design(ctx); // legalise_design(ctx);
// FIXME
require_legal = true; require_legal = true;
autoplaced.clear(); autoplaced.clear();
for (auto cell : sorted(ctx->cells)) { for (auto cell : sorted(ctx->cells)) {

2
ecp5/config.h
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@ -20,8 +20,8 @@
#ifndef ECP5_CONFIG_H #ifndef ECP5_CONFIG_H
#define ECP5_CONFIG_H #define ECP5_CONFIG_H
#include "nextpnr.h"
#include <map> #include <map>
#include "nextpnr.h"
NEXTPNR_NAMESPACE_BEGIN NEXTPNR_NAMESPACE_BEGIN

26
ecp5/place_legaliser.cc
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@ -1,26 +0,0 @@
/*
* nextpnr -- Next Generation Place and Route
*
* Copyright (C) 2018 David Shah <david@symbioticeda.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 "place_legaliser.h"
NEXTPNR_NAMESPACE_BEGIN
bool legalise_design(Context *ctx) { return true; }
NEXTPNR_NAMESPACE_END

31
ecp5/place_legaliser.h
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@ -1,31 +0,0 @@
/*
* nextpnr -- Next Generation Place and Route
*
* Copyright (C) 2018 David Shah <david@symbioticeda.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.
*
*/
#ifndef PLACE_LEGALISER_H
#define PLACE_LEGALISER_H
#include "nextpnr.h"
NEXTPNR_NAMESPACE_BEGIN
bool legalise_design(Context *ctx);
NEXTPNR_NAMESPACE_END
#endif

26
generic/place_legaliser.cc
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@ -1,26 +0,0 @@
/*
* nextpnr -- Next Generation Place and Route
*
* Copyright (C) 2018 David Shah <david@symbioticeda.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 "place_legaliser.h"
NEXTPNR_NAMESPACE_BEGIN
bool legalise_design(Context *ctx) { return true; }
NEXTPNR_NAMESPACE_END

31
generic/place_legaliser.h
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@ -1,31 +0,0 @@
/*
* nextpnr -- Next Generation Place and Route
*
* Copyright (C) 2018 David Shah <david@symbioticeda.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.
*
*/
#ifndef PLACE_LEGALISER_H
#define PLACE_LEGALISER_H
#include "nextpnr.h"
NEXTPNR_NAMESPACE_BEGIN
bool legalise_design(Context *ctx);
NEXTPNR_NAMESPACE_END
#endif

282
ice40/chains.cc Normal file
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@ -0,0 +1,282 @@
/*
* nextpnr -- Next Generation Place and Route
*
* Copyright (C) 2018 David Shah <clifford@symbioticeda.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 "chains.h"
#include <algorithm>
#include <vector>
#include "cells.h"
#include "design_utils.h"
#include "log.h"
#include "place_common.h"
#include "util.h"
NEXTPNR_NAMESPACE_BEGIN
struct CellChain
{
std::vector<CellInfo *> cells;
};
// Generic chain finder
template <typename F1, typename F2, typename F3>
std::vector<CellChain> find_chains(const Context *ctx, F1 cell_type_predicate, F2 get_previous, F3 get_next,
size_t min_length = 2)
{
std::set<IdString> chained;
std::vector<CellChain> chains;
for (auto cell : sorted(ctx->cells)) {
if (chained.find(cell.first) != chained.end())
continue;
CellInfo *ci = cell.second;
if (cell_type_predicate(ctx, ci)) {
CellInfo *start = ci;
CellInfo *prev_start = ci;
while (prev_start != nullptr) {
start = prev_start;
prev_start = get_previous(ctx, start);
}
CellChain chain;
CellInfo *end = start;
while (end != nullptr) {
chain.cells.push_back(end);
end = get_next(ctx, end);
}
if (chain.cells.size() >= min_length) {
chains.push_back(chain);
for (auto c : chain.cells)
chained.insert(c->name);
}
}
}
return chains;
}
class ChainConstrainer
{
private:
Context *ctx;
// Split a carry chain into multiple legal chains
std::vector<CellChain> split_carry_chain(CellChain &carryc)
{
bool start_of_chain = true;
std::vector<CellChain> chains;
std::vector<const CellInfo *> tile;
const int max_length = (ctx->chip_info->height - 2) * 8 - 2;
auto curr_cell = carryc.cells.begin();
while (curr_cell != carryc.cells.end()) {
CellInfo *cell = *curr_cell;
if (tile.size() >= 8) {
tile.clear();
}
if (start_of_chain) {
tile.clear();
chains.emplace_back();
start_of_chain = false;
if (cell->ports.at(ctx->id("CIN")).net) {
// CIN is not constant and not part of a chain. Must feed in from fabric
CellInfo *feedin = make_carry_feed_in(cell, cell->ports.at(ctx->id("CIN")));
chains.back().cells.push_back(feedin);
tile.push_back(feedin);
}
}
tile.push_back(cell);
chains.back().cells.push_back(cell);
bool split_chain = (!ctx->logicCellsCompatible(tile)) || (int(chains.back().cells.size()) > max_length);
if (split_chain) {
CellInfo *passout = make_carry_pass_out(cell->ports.at(ctx->id("COUT")));
tile.pop_back();
chains.back().cells.back() = passout;
start_of_chain = true;
} else {
NetInfo *carry_net = cell->ports.at(ctx->id("COUT")).net;
bool at_end = (curr_cell == carryc.cells.end() - 1);
if (carry_net != nullptr && (carry_net->users.size() > 1 || at_end)) {
if (carry_net->users.size() > 2 ||
(net_only_drives(ctx, carry_net, is_lc, ctx->id("I3"), false) !=
net_only_drives(ctx, carry_net, is_lc, ctx->id("CIN"), false)) ||
(at_end && !net_only_drives(ctx, carry_net, is_lc, ctx->id("I3"), true))) {
CellInfo *passout = make_carry_pass_out(cell->ports.at(ctx->id("COUT")));
chains.back().cells.push_back(passout);
tile.push_back(passout);
start_of_chain = true;
}
}
++curr_cell;
}
}
return chains;
}
// Insert a logic cell to legalise a COUT->fabric connection
CellInfo *make_carry_pass_out(PortInfo &cout_port)
{
NPNR_ASSERT(cout_port.net != nullptr);
std::unique_ptr<CellInfo> lc = create_ice_cell(ctx, ctx->id("ICESTORM_LC"));
lc->params[ctx->id("LUT_INIT")] = "65280"; // 0xff00: O = I3
lc->params[ctx->id("CARRY_ENABLE")] = "1";
lc->ports.at(ctx->id("O")).net = cout_port.net;
std::unique_ptr<NetInfo> co_i3_net(new NetInfo());
co_i3_net->name = ctx->id(lc->name.str(ctx) + "$I3");
co_i3_net->driver = cout_port.net->driver;
PortRef i3_r;
i3_r.port = ctx->id("I3");
i3_r.cell = lc.get();
co_i3_net->users.push_back(i3_r);
PortRef o_r;
o_r.port = ctx->id("O");
o_r.cell = lc.get();
cout_port.net->driver = o_r;
lc->ports.at(ctx->id("I3")).net = co_i3_net.get();
cout_port.net = co_i3_net.get();
IdString co_i3_name = co_i3_net->name;
NPNR_ASSERT(ctx->nets.find(co_i3_name) == ctx->nets.end());
ctx->nets[co_i3_name] = std::move(co_i3_net);
IdString name = lc->name;
ctx->assignCellInfo(lc.get());
ctx->cells[lc->name] = std::move(lc);
return ctx->cells[name].get();
}
// Insert a logic cell to legalise a CIN->fabric connection
CellInfo *make_carry_feed_in(CellInfo *cin_cell, PortInfo &cin_port)
{
NPNR_ASSERT(cin_port.net != nullptr);
std::unique_ptr<CellInfo> lc = create_ice_cell(ctx, ctx->id("ICESTORM_LC"));
lc->params[ctx->id("CARRY_ENABLE")] = "1";
lc->params[ctx->id("CIN_CONST")] = "1";
lc->params[ctx->id("CIN_SET")] = "1";
lc->ports.at(ctx->id("I1")).net = cin_port.net;
cin_port.net->users.erase(std::remove_if(cin_port.net->users.begin(), cin_port.net->users.end(),
[cin_cell, cin_port](const PortRef &usr) {
return usr.cell == cin_cell && usr.port == cin_port.name;
}));
PortRef i1_ref;
i1_ref.cell = lc.get();
i1_ref.port = ctx->id("I1");
lc->ports.at(ctx->id("I1")).net->users.push_back(i1_ref);
std::unique_ptr<NetInfo> out_net(new NetInfo());
out_net->name = ctx->id(lc->name.str(ctx) + "$O");
PortRef drv_ref;
drv_ref.port = ctx->id("COUT");
drv_ref.cell = lc.get();
out_net->driver = drv_ref;
lc->ports.at(ctx->id("COUT")).net = out_net.get();
PortRef usr_ref;
usr_ref.port = cin_port.name;
usr_ref.cell = cin_cell;
out_net->users.push_back(usr_ref);
cin_cell->ports.at(cin_port.name).net = out_net.get();
IdString out_net_name = out_net->name;
NPNR_ASSERT(ctx->nets.find(out_net_name) == ctx->nets.end());
ctx->nets[out_net_name] = std::move(out_net);
IdString name = lc->name;
ctx->assignCellInfo(lc.get());
ctx->cells[lc->name] = std::move(lc);
return ctx->cells[name].get();
}
void process_carries()
{
std::vector<CellChain> carry_chains =
find_chains(ctx, [](const Context *ctx, const CellInfo *cell) { return is_lc(ctx, cell); },
[](const Context *ctx, const
CellInfo *cell) {
CellInfo *carry_prev =
net_driven_by(ctx, cell->ports.at(ctx->id("CIN")).net, is_lc, ctx->id("COUT"));
if (carry_prev != nullptr)
return carry_prev;
/*CellInfo *i3_prev = net_driven_by(ctx, cell->ports.at(ctx->id("I3")).net, is_lc,
ctx->id("COUT")); if (i3_prev != nullptr) return i3_prev;*/
return (CellInfo *)nullptr;
},
[](const Context *ctx, const CellInfo *cell) {
CellInfo *carry_next = net_only_drives(ctx, cell->ports.at(ctx->id("COUT")).net, is_lc,
ctx->id("CIN"), false);
if (carry_next != nullptr)
return carry_next;
/*CellInfo *i3_next =
net_only_drives(ctx, cell->ports.at(ctx->id("COUT")).net, is_lc, ctx->id("I3"),
false); if (i3_next != nullptr) return i3_next;*/
return (CellInfo *)nullptr;
});
std::unordered_set<IdString> chained;
for (auto &base_chain : carry_chains) {
for (auto c : base_chain.cells)
chained.insert(c->name);
}
// Any cells not in chains, but with carry enabled, must also be put in a single-carry chain
// for correct processing
for (auto cell : sorted(ctx->cells)) {
CellInfo *ci = cell.second;
if (chained.find(cell.first) == chained.end() && is_lc(ctx, ci) &&
bool_or_default(ci->params, ctx->id("CARRY_ENABLE"))) {
CellChain sChain;
sChain.cells.push_back(ci);
chained.insert(cell.first);
carry_chains.push_back(sChain);
}
}
std::vector<CellChain> all_chains;
// Chain splitting
for (auto &base_chain : carry_chains) {
if (ctx->verbose) {
log_info("Found carry chain: \n");
for (auto entry : base_chain.cells)
log_info(" %s\n", entry->name.c_str(ctx));
log_info("\n");
}
std::vector<CellChain> split_chains = split_carry_chain(base_chain);
for (auto &chain : split_chains) {
all_chains.push_back(chain);
}
}
// Actual chain placement
for (auto &chain : all_chains) {
if (ctx->verbose)
log_info("Placing carry chain starting at '%s'\n", chain.cells.front()->name.c_str(ctx));
// Place carry chain
chain.cells.at(0)->constr_abs_z = 0;
for (int i = 1; i < int(chain.cells.size()); i++) {
chain.cells.at(i)->constr_x = 0;
chain.cells.at(i)->constr_y = (i / 8);
chain.cells.at(i)->constr_z = i % 8;
chain.cells.at(i)->constr_abs_z = true;
chain.cells.at(i)->constr_parent = chain.cells.at(0);
chain.cells.at(0)->constr_children.push_back(chain.cells.at(i));
}
}
}
public:
ChainConstrainer(Context *ctx) : ctx(ctx){};
void constrain_chains() { process_carries(); }
};
void constrain_chains(Context *ctx) { ChainConstrainer(ctx).constrain_chains(); }
NEXTPNR_NAMESPACE_END

10
ice40/place_legaliser.h → ice40/chains.h
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@ -1,7 +1,7 @@
/* /*
* nextpnr -- Next Generation Place and Route * nextpnr -- Next Generation Place and Route
* *
* Copyright (C) 2018 David Shah <david@symbioticeda.com> * Copyright (C) 2018 David Shah <clifford@symbioticeda.com>
* *
* Permission to use, copy, modify, and/or distribute this software for any * Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above * purpose with or without fee is hereby granted, provided that the above
@ -17,15 +17,11 @@
* *
*/ */
#ifndef PLACE_LEGALISER_H
#define PLACE_LEGALISER_H
#include "nextpnr.h" #include "nextpnr.h"
NEXTPNR_NAMESPACE_BEGIN NEXTPNR_NAMESPACE_BEGIN
bool legalise_design(Context *ctx); // This finds chains, inserts LCs to legalise them as needed, and sets relative constraints as appropriate
void constrain_chains(Context *ctx);
NEXTPNR_NAMESPACE_END NEXTPNR_NAMESPACE_END
#endif

1
ice40/main.cc
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@ -40,7 +40,6 @@
#include "log.h" #include "log.h"
#include "nextpnr.h" #include "nextpnr.h"
#include "pcf.h" #include "pcf.h"
#include "place_legaliser.h"
#include "timing.h" #include "timing.h"
#include "version.h" #include "version.h"

554
ice40/place_legaliser.cc
View File

@ -1,554 +0,0 @@
/*
* nextpnr -- Next Generation Place and Route
*
* Copyright (C) 2018 David Shah <david@symbioticeda.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 "place_legaliser.h"
#include <algorithm>
#include <vector>
#include "cells.h"
#include "design_utils.h"
#include "log.h"
#include "place_common.h"
#include "util.h"
NEXTPNR_NAMESPACE_BEGIN
struct CellChain
{
std::vector<CellInfo *> cells;
float mid_x = 0, mid_y = 0;
};
// Generic chain finder
template <typename F1, typename F2, typename F3>
std::vector<CellChain> find_chains(const Context *ctx, F1 cell_type_predicate, F2 get_previous, F3 get_next,
size_t min_length = 2)
{
std::set<IdString> chained;
std::vector<CellChain> chains;
for (auto cell : sorted(ctx->cells)) {
if (chained.find(cell.first) != chained.end())
continue;
CellInfo *ci = cell.second;
if (cell_type_predicate(ctx, ci)) {
CellInfo *start = ci;
CellInfo *prev_start = ci;
while (prev_start != nullptr) {
start = prev_start;
prev_start = get_previous(ctx, start);
}
CellChain chain;
CellInfo *end = start;
while (end != nullptr) {
chain.cells.push_back(end);
end = get_next(ctx, end);
}
if (chain.cells.size() >= min_length) {
chains.push_back(chain);
for (auto c : chain.cells)
chained.insert(c->name);
}
}
}
return chains;
}
static void get_chain_midpoint(const Context *ctx, const CellChain &chain, float &x, float &y)
{
float total_x = 0, total_y = 0;
int N = 0;
for (auto cell : chain.cells) {
if (cell->bel == BelId())
continue;
Loc bel_loc = ctx->getBelLocation(cell->bel);
total_x += bel_loc.x;
total_y += bel_loc.y;
N++;
}
NPNR_ASSERT(N > 0);
x = total_x / N;
y = total_y / N;
}
static int get_cell_evilness(const Context *ctx, const CellInfo *cell)
{
// This returns how "evil" a logic cell is, and thus how likely it is to be ripped up
// during logic tile legalisation
int score = 0;
if (get_net_or_empty(cell, ctx->id_i0))
++score;
if (get_net_or_empty(cell, ctx->id_i1))
++score;
if (get_net_or_empty(cell, ctx->id_i2))
++score;
if (get_net_or_empty(cell, ctx->id_i3))
++score;
if (cell->lcInfo.dffEnable) {
if (cell->lcInfo.cen)
score += 10;
if (cell->lcInfo.sr)
score += 10;
if (cell->lcInfo.negClk)
score += 5;
}
return score;
}
class PlacementLegaliser
{
public:
PlacementLegaliser(Context *ctx) : ctx(ctx){};
void print_stats(const char *point)
{
float distance_sum = 0;
float max_distance = 0;
int moved_cells = 0;
int unplaced_cells = 0;
for (auto orig : originalPositions) {
if (ctx->cells.at(orig.first)->bel == BelId()) {
unplaced_cells++;
continue;
}
Loc newLoc = ctx->getBelLocation(ctx->cells.at(orig.first)->bel);
if (newLoc != orig.second) {
float distance = std::sqrt(std::pow(newLoc.x - orig.second.x, 2) + pow(newLoc.y - orig.second.y, 2));
moved_cells++;
distance_sum += distance;
if (distance > max_distance)
max_distance = distance;
}
}
log_info(" moved %d cells, %d unplaced (after %s)\n", moved_cells, unplaced_cells, point);
if (moved_cells > 0) {
log_info(" average distance %f\n", (distance_sum / moved_cells));
log_info(" maximum distance %f\n", max_distance);
}
}
bool legalise()
{
log_info("Legalising design..\n");
for (auto &cell : ctx->cells) {
CellInfo *ci = cell.second.get();
if (!ctx->getBelGlobalBuf(ci->bel) && cell.second->type == ctx->id("ICESTORM_LC")) {
originalPositions[cell.first] = ctx->getBelLocation(ci->bel);
}
}
init_logic_cells();
bool legalised_carries = legalise_carries();
if (!legalised_carries && !ctx->force)
return false;
print_stats("carry legalisation");
legalise_others();
print_stats("misc. cell legalisation");
legalise_logic_tiles();
print_stats("logic cell legalisation");
bool replaced_cells = replace_cells();
print_stats("cell replacement");
ctx->assignArchInfo();
return legalised_carries && replaced_cells;
}
private:
void init_logic_cells()
{
for (auto bel : ctx->getBels()) {
// Initialise the logic bels vector with unavailable invalid bels, dimensions [0..width][0..height[0..7]
logic_bels.resize(ctx->chip_info->width + 1,
std::vector<std::vector<std::pair<BelId, bool>>>(
ctx->chip_info->height + 1,
std::vector<std::pair<BelId, bool>>(8, std::make_pair(BelId(), true))));
if (ctx->getBelType(bel) == TYPE_ICESTORM_LC) {
// Using the non-standard API here to get (x, y, z) rather than just (x, y)
auto bi = ctx->chip_info->bel_data[bel.index];
int x = bi.x, y = bi.y, z = bi.z;
IdString cell = ctx->getBoundBelCell(bel);
if (cell != IdString() && ctx->cells.at(cell)->belStrength >= STRENGTH_FIXED)
logic_bels.at(x).at(y).at(z) = std::make_pair(bel, true); // locked out of use
else
logic_bels.at(x).at(y).at(z) = std::make_pair(bel, false); // available
}
}
}
bool legalise_carries()
{
std::vector<CellChain> carry_chains =
find_chains(ctx, [](const Context *ctx, const CellInfo *cell) { return is_lc(ctx, cell); },
[](const Context *ctx, const
CellInfo *cell) {
CellInfo *carry_prev =
net_driven_by(ctx, cell->ports.at(ctx->id("CIN")).net, is_lc, ctx->id("COUT"));
if (carry_prev != nullptr)
return carry_prev;
/*CellInfo *i3_prev = net_driven_by(ctx, cell->ports.at(ctx->id("I3")).net, is_lc,
ctx->id("COUT")); if (i3_prev != nullptr) return i3_prev;*/
return (CellInfo *)nullptr;
},
[](const Context *ctx, const CellInfo *cell) {
CellInfo *carry_next = net_only_drives(ctx, cell->ports.at(ctx->id("COUT")).net, is_lc,
ctx->id("CIN"), false);
if (carry_next != nullptr)
return carry_next;
/*CellInfo *i3_next =
net_only_drives(ctx, cell->ports.at(ctx->id("COUT")).net, is_lc, ctx->id("I3"),
false); if (i3_next != nullptr) return i3_next;*/
return (CellInfo *)nullptr;
});
std::unordered_set<IdString> chained;
for (auto &base_chain : carry_chains) {
for (auto c : base_chain.cells)
chained.insert(c->name);
}
// Any cells not in chains, but with carry enabled, must also be put in a single-carry chain
// for correct processing
for (auto cell : sorted(ctx->cells)) {
CellInfo *ci = cell.second;
if (chained.find(cell.first) == chained.end() && is_lc(ctx, ci) &&
bool_or_default(ci->params, ctx->id("CARRY_ENABLE"))) {
CellChain sChain;
sChain.cells.push_back(ci);
chained.insert(cell.first);
carry_chains.push_back(sChain);
}
}
bool success = true;
// Find midpoints for all chains, before we start tearing them up
std::vector<CellChain> all_chains;
for (auto &base_chain : carry_chains) {
if (ctx->verbose) {
log_info("Found carry chain: \n");
for (auto entry : base_chain.cells)
log_info(" %s\n", entry->name.c_str(ctx));
log_info("\n");
}
std::vector<CellChain> split_chains = split_carry_chain(base_chain);
for (auto &chain : split_chains) {
get_chain_midpoint(ctx, chain, chain.mid_x, chain.mid_y);
all_chains.push_back(chain);
}
}
// Actual chain placement
for (auto &chain : all_chains) {
if (ctx->verbose)
log_info("Placing carry chain starting at '%s'\n", chain.cells.front()->name.c_str(ctx));
float base_x = chain.mid_x, base_y = chain.mid_y - (chain.cells.size() / 16.0f);
// Find Bel meeting requirements closest to the target base, returning location as <x, y, z>
auto chain_origin_bel = find_closest_bel(base_x, base_y, chain);
int place_x = std::get<0>(chain_origin_bel), place_y = std::get<1>(chain_origin_bel),
place_z = std::get<2>(chain_origin_bel);
if (place_x == -1) {
if (ctx->force) {
log_warning("failed to place carry chain, starting with cell '%s', length %d\n",
chain.cells.front()->name.c_str(ctx), int(chain.cells.size()));
success = false;
continue;
} else {
log_error("failed to place carry chain, starting with cell '%s', length %d\n",
chain.cells.front()->name.c_str(ctx), int(chain.cells.size()));
}
}
// Place carry chain
for (int i = 0; i < int(chain.cells.size()); i++) {
int target_z = place_y * 8 + place_z + i;
place_lc(chain.cells.at(i), place_x, target_z / 8, target_z % 8);
if (ctx->verbose)
log_info(" Cell '%s' placed at (%d, %d, %d)\n", chain.cells.at(i)->name.c_str(ctx), place_x,
target_z / 8, target_z % 8);
}
}
return success;
}
// Find Bel closest to a location, meeting chain requirements
std::tuple<int, int, int> find_closest_bel(float target_x, float target_y, CellChain &chain)
{
std::tuple<int, int, int> best_origin = std::make_tuple(-1, -1, -1);
wirelen_t best_metric = std::numeric_limits<wirelen_t>::max();
int width = ctx->chip_info->width, height = ctx->chip_info->height;
// Slow, should radiate outwards from target position - TODO
int chain_size = int(chain.cells.size());
for (int x = 1; x < width; x++) {
for (int y = 1; y < (height - (chain_size / 8)); y++) {
bool valid = true;
wirelen_t wirelen = 0;
for (int k = 0; k < chain_size; k++) {
auto &lb = logic_bels.at(x).at(y + k / 8).at(k % 8);
if (lb.second) {
valid = false;
break;
} else {
wirelen += get_cell_metric_at_bel(ctx, chain.cells.at(k), lb.first, MetricType::COST);
}
}
if (valid && wirelen < best_metric) {
best_metric = wirelen;
best_origin = std::make_tuple(x, y, 0);
}
}
}
return best_origin;
}
// Split a carry chain into multiple legal chains
std::vector<CellChain> split_carry_chain(CellChain &carryc)
{
bool start_of_chain = true;
std::vector<CellChain> chains;
std::vector<const CellInfo *> tile;
const int max_length = (ctx->chip_info->height - 2) * 8 - 2;
auto curr_cell = carryc.cells.begin();
while (curr_cell != carryc.cells.end()) {
CellInfo *cell = *curr_cell;
if (tile.size() >= 8) {
tile.clear();
}
if (start_of_chain) {
tile.clear();
chains.emplace_back();
start_of_chain = false;
if (cell->ports.at(ctx->id("CIN")).net) {
// CIN is not constant and not part of a chain. Must feed in from fabric
CellInfo *feedin = make_carry_feed_in(cell, cell->ports.at(ctx->id("CIN")));
chains.back().cells.push_back(feedin);
tile.push_back(feedin);
}
}
tile.push_back(cell);
chains.back().cells.push_back(cell);
bool split_chain = (!ctx->logicCellsCompatible(tile)) || (int(chains.back().cells.size()) > max_length);
if (split_chain) {
CellInfo *passout = make_carry_pass_out(cell->ports.at(ctx->id("COUT")));
tile.pop_back();
chains.back().cells.back() = passout;
start_of_chain = true;
} else {
NetInfo *carry_net = cell->ports.at(ctx->id("COUT")).net;
bool at_end = (curr_cell == carryc.cells.end() - 1);
if (carry_net != nullptr && (carry_net->users.size() > 1 || at_end)) {
if (carry_net->users.size() > 2 ||
(net_only_drives(ctx, carry_net, is_lc, ctx->id("I3"), false) !=
net_only_drives(ctx, carry_net, is_lc, ctx->id("CIN"), false)) ||
(at_end && !net_only_drives(ctx, carry_net, is_lc, ctx->id("I3"), true))) {
CellInfo *passout = make_carry_pass_out(cell->ports.at(ctx->id("COUT")));
chains.back().cells.push_back(passout);
tile.push_back(passout);
start_of_chain = true;
}
}
++curr_cell;
}
}
return chains;
}
// Place a logic cell at a given grid location, handling rip-up etc
void place_lc(CellInfo *cell, int x, int y, int z)
{
auto &loc = logic_bels.at(x).at(y).at(z);
NPNR_ASSERT(!loc.second);
BelId bel = loc.first;
// Check if there is a cell presently at the location, which we will need to rip up
IdString existing = ctx->getBoundBelCell(bel);
if (existing != IdString()) {
// TODO: keep track of the previous position of the ripped up cell, as a hint
rippedCells.insert(existing);
ctx->unbindBel(bel);
}
if (cell->bel != BelId()) {
ctx->unbindBel(cell->bel);
}
ctx->bindBel(bel, cell->name, STRENGTH_LOCKED);
rippedCells.erase(cell->name); // If cell was ripped up previously, no need to re-place
loc.second = true; // Bel is now unavailable for further use
}
// Insert a logic cell to legalise a COUT->fabric connection
CellInfo *make_carry_pass_out(PortInfo &cout_port)
{
NPNR_ASSERT(cout_port.net != nullptr);
std::unique_ptr<CellInfo> lc = create_ice_cell(ctx, ctx->id("ICESTORM_LC"));
lc->params[ctx->id("LUT_INIT")] = "65280"; // 0xff00: O = I3
lc->params[ctx->id("CARRY_ENABLE")] = "1";
lc->ports.at(ctx->id("O")).net = cout_port.net;
std::unique_ptr<NetInfo> co_i3_net(new NetInfo());
co_i3_net->name = ctx->id(lc->name.str(ctx) + "$I3");
co_i3_net->driver = cout_port.net->driver;
PortRef i3_r;
i3_r.port = ctx->id("I3");
i3_r.cell = lc.get();
co_i3_net->users.push_back(i3_r);
PortRef o_r;
o_r.port = ctx->id("O");
o_r.cell = lc.get();
cout_port.net->driver = o_r;
lc->ports.at(ctx->id("I3")).net = co_i3_net.get();
cout_port.net = co_i3_net.get();
IdString co_i3_name = co_i3_net->name;
NPNR_ASSERT(ctx->nets.find(co_i3_name) == ctx->nets.end());
ctx->nets[co_i3_name] = std::move(co_i3_net);
IdString name = lc->name;
ctx->assignCellInfo(lc.get());
ctx->cells[lc->name] = std::move(lc);
createdCells.insert(name);
return ctx->cells[name].get();
}
// Insert a logic cell to legalise a CIN->fabric connection
CellInfo *make_carry_feed_in(CellInfo *cin_cell, PortInfo &cin_port)
{
NPNR_ASSERT(cin_port.net != nullptr);
std::unique_ptr<CellInfo> lc = create_ice_cell(ctx, ctx->id("ICESTORM_LC"));
lc->params[ctx->id("CARRY_ENABLE")] = "1";
lc->params[ctx->id("CIN_CONST")] = "1";
lc->params[ctx->id("CIN_SET")] = "1";
lc->ports.at(ctx->id("I1")).net = cin_port.net;
cin_port.net->users.erase(std::remove_if(cin_port.net->users.begin(), cin_port.net->users.end(),
[cin_cell, cin_port](const PortRef &usr) {
return usr.cell == cin_cell && usr.port == cin_port.name;
}));
PortRef i1_ref;
i1_ref.cell = lc.get();
i1_ref.port = ctx->id("I1");
lc->ports.at(ctx->id("I1")).net->users.push_back(i1_ref);
std::unique_ptr<NetInfo> out_net(new NetInfo());
out_net->name = ctx->id(lc->name.str(ctx) + "$O");
PortRef drv_ref;
drv_ref.port = ctx->id("COUT");
drv_ref.cell = lc.get();
out_net->driver = drv_ref;
lc->ports.at(ctx->id("COUT")).net = out_net.get();
PortRef usr_ref;
usr_ref.port = cin_port.name;
usr_ref.cell = cin_cell;
out_net->users.push_back(usr_ref);
cin_cell->ports.at(cin_port.name).net = out_net.get();
IdString out_net_name = out_net->name;
NPNR_ASSERT(ctx->nets.find(out_net_name) == ctx->nets.end());
ctx->nets[out_net_name] = std::move(out_net);
IdString name = lc->name;
ctx->assignCellInfo(lc.get());
ctx->cells[lc->name] = std::move(lc);
createdCells.insert(name);
return ctx->cells[name].get();
}
// Legalise logic tiles
void legalise_logic_tiles()
{
int width = ctx->chip_info->width, height = ctx->chip_info->height;
for (int x = 1; x < width; x++) {
for (int y = 1; y < height; y++) {
BelId tileBel = logic_bels.at(x).at(y).at(0).first;
if (tileBel != BelId()) {
bool changed = true;
while (!ctx->isBelLocationValid(tileBel) && changed) {
changed = false;
int max_score = 0;
CellInfo *target = nullptr;
for (int z = 0; z < 8; z++) {
BelId bel = logic_bels.at(x).at(y).at(z).first;
IdString cell = ctx->getBoundBelCell(bel);
if (cell != IdString()) {
CellInfo *ci = ctx->cells.at(cell).get();
if (ci->belStrength >= STRENGTH_STRONG)
continue;
int score = get_cell_evilness(ctx, ci);
if (score > max_score) {
max_score = score;
target = ci;
}
}
}
if (target != nullptr) {
ctx->unbindBel(target->bel);
rippedCells.insert(target->name);
changed = true;
}
}
}
}
}
}
// Legalise other tiles
void legalise_others()
{
std::vector<CellInfo *> legalised_others;
for (auto cell : sorted(ctx->cells)) {
CellInfo *ci = cell.second;
if (!is_lc(ctx, ci)) {
if (ci->belStrength < STRENGTH_STRONG && ci->bel != BelId()) {
if (!ctx->isValidBelForCell(ci, ci->bel)) {
place_single_cell(ctx, ci, true);
}
legalised_others.push_back(ci);
}
}
}
// Lock all these cells now, we don't need to move them in SA (don't lock during legalise placement
// so legalise placement can rip up in case of gbuf contention etc)
for (auto cell : legalised_others)
cell->belStrength = STRENGTH_STRONG;
}
// Replace ripped-up cells
bool replace_cells()
{
bool success = true;
for (auto cell : sorted(rippedCells)) {
CellInfo *ci = ctx->cells.at(cell).get();
bool placed = place_single_cell(ctx, ci, true);
if (!placed) {
if (ctx->force) {
log_warning("failed to place cell '%s' of type '%s'\n", cell.c_str(ctx), ci->type.c_str(ctx));
success = false;
} else {
log_error("failed to place cell '%s' of type '%s'\n", cell.c_str(ctx), ci->type.c_str(ctx));
}
}
}
return success;
}
Context *ctx;
std::unordered_set<IdString> rippedCells;
std::unordered_set<IdString> createdCells;
std::unordered_map<IdString, Loc> originalPositions;
// Go from X and Y position to logic cells, setting occupied to true if a Bel is unavailable
std::vector<std::vector<std::vector<std::pair<BelId, bool>>>> logic_bels;
};
bool legalise_design(Context *ctx)
{
PlacementLegaliser lg(ctx);
return lg.legalise();
}
NEXTPNR_NAMESPACE_END