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/*
* nextpnr -- Next Generation Place and Route
*
* Copyright (C) 2018 David Shah <david@symbioticeda.com>
* Copyright (C) 2018 Serge Bazanski <q3k@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_common.h"
#include <cmath>
#include "log.h"
#include "util.h"
NEXTPNR_NAMESPACE_BEGIN
// Placing a single cell
bool place_single_cell(ArchRWProxy &proxy, Context *ctx, CellInfo *cell, bool require_legality)
{
bool all_placed = false;
int iters = 25;
while (!all_placed) {
BelId best_bel = BelId();
wirelen_t best_wirelen = std::numeric_limits<wirelen_t>::max(),
best_ripup_wirelen = std::numeric_limits<wirelen_t>::max();
CellInfo *ripup_target = nullptr;
BelId ripup_bel = BelId();
if (cell->bel != BelId()) {
proxy.unbindBel(cell->bel);
}
BelType targetType = ctx->belTypeFromId(cell->type);
for (auto bel : ctx->getBels()) {
if (ctx->getBelType(bel) == targetType && (!require_legality || proxy.isValidBelForCell(cell, bel))) {
if (proxy.checkBelAvail(bel)) {
wirelen_t wirelen = get_cell_wirelength_at_bel(proxy, ctx, cell, bel);
if (iters >= 4)
wirelen += ctx->rng(25);
if (wirelen <= best_wirelen) {
best_wirelen = wirelen;
best_bel = bel;
}
} else {
wirelen_t wirelen = get_cell_wirelength_at_bel(proxy, ctx, cell, bel);
if (iters >= 4)
wirelen += ctx->rng(25);
if (wirelen <= best_ripup_wirelen) {
ripup_target = proxy.getCell(proxy.getBoundBelCell(bel));
if (ripup_target->belStrength < STRENGTH_STRONG) {
best_ripup_wirelen = wirelen;
ripup_bel = bel;
}
}
}
}
}
if (best_bel == BelId()) {
if (iters == 0) {
log_error("failed to place cell '%s' of type '%s' (ripup iteration limit exceeded)\n",
cell->name.c_str(ctx), cell->type.c_str(ctx));
}
if (ripup_bel == BelId()) {
log_error("failed to place cell '%s' of type '%s'\n", cell->name.c_str(ctx), cell->type.c_str(ctx));
}
--iters;
proxy.unbindBel(ripup_target->bel);
best_bel = ripup_bel;
} else {
all_placed = true;
}
proxy.bindBel(best_bel, cell->name, STRENGTH_WEAK);
cell = ripup_target;
}
return true;
}
NEXTPNR_NAMESPACE_END
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