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/*
* nextpnr -- Next Generation Place and Route
*
* Copyright (C) 2021 Symbiflow Authors
*
* 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 LUTS_H
#define LUTS_H
#include <unordered_map>
#include <unordered_set>
#include "idstring.h"
#include "nextpnr_namespaces.h"
#include "dynamic_bitarray.h"
#include "hash_table.h"
NEXTPNR_NAMESPACE_BEGIN
struct CellInfo;
struct Context;
enum LogicLevel
{
LL_Zero,
LL_One,
LL_DontCare
};
struct LutCell
{
// LUT cell pins for equation, LSB first.
std::vector<IdString> pins;
std::unordered_set<IdString> lut_pins;
std::unordered_set<IdString> vcc_pins;
DynamicBitarray<> equation;
};
struct LutBel
{
IdString name;
// LUT BEL pins to LUT array index.
std::vector<IdString> pins;
std::unordered_map<IdString, size_t> pin_to_index;
IdString output_pin;
// What part of the LUT equation does this LUT output use?
// This assumes contiguous LUT bits.
uint32_t low_bit;
uint32_t high_bit;
int32_t min_pin;
int32_t max_pin;
};
// Work forward from cell definition and cell -> bel pin map and check that
// equation is valid.
void check_equation(const LutCell &lut_cell, const std::unordered_map<IdString, IdString> &cell_to_bel_map,
const LutBel &lut_bel, const std::vector<LogicLevel> &equation, uint32_t used_pins);
struct LutElement
{
size_t width;
std::unordered_map<IdString, LutBel> lut_bels;
void compute_pin_order();
std::vector<IdString> pins;
std::unordered_map<IdString, size_t> pin_to_index;
};
struct LutMapper
{
LutMapper(const LutElement &element) : element(element) {}
const LutElement &element;
std::vector<CellInfo *> cells;
bool remap_luts(const Context *ctx, HashTables::HashSet<const LutBel *> *blocked_luts);
// Determine which wires given the current mapping must be tied to the
// default constant.
//
// Returns a bit mask, 1 meaning it must be tied. Otherwise means that
// the pin is free to be a signal.
uint32_t check_wires(const std::vector<std::vector<int32_t>> &bel_to_cell_pin_remaps,
const std::vector<const LutBel *> &lut_bels, uint32_t used_pins,
HashTables::HashSet<const LutBel *> *blocked_luts) const;
// Version of check_wires that uses current state of cells based on pin
// mapping in cells variable.
uint32_t check_wires(const Context *ctx) const;
};
// Rotate and merge a LUT equation into an array of levels.
//
// If a conflict arises, return false and result is in an indeterminate state.
bool rotate_and_merge_lut_equation(std::vector<LogicLevel> *result, const LutBel &lut_bel,
const DynamicBitarray<> &old_equation, const std::vector<size_t> &pin_map,
uint32_t used_pins);
NEXTPNR_NAMESPACE_END
#endif /* LUTS_H */
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