fe4608386e
"nextpnr.h" is no longer the god header. Important improvements: - Functions in log.h can be used without including BaseCtx/Arch/Context. This means that log_X functions can be called without included "nextpnr.h" - NPNR_ASSERT can be used without including "nextpnr.h" by including "nextpnr_assertions.h". This allows NPNR_ASSERT to be used safely in any header file. - Types defined in "archdefs.h" are now available without including BaseCtx/Arch/Context. This means that utility classes that will be used inside of BaseCtx/Arch/Context can be defined safely in a self-contained header. Signed-off-by: Keith Rothman <537074+litghost@users.noreply.github.com>
104 lines
2.6 KiB
C++
104 lines
2.6 KiB
C++
/*
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* nextpnr -- Next Generation Place and Route
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*
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* Copyright (C) 2018 Clifford Wolf <clifford@symbioticeda.com>
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* Copyright (C) 2018 Serge Bazanski <q3k@symbioticeda.com>
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*
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* Permission to use, copy, modify, and/or distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*
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*/
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#ifndef DETERMINISTIC_RNG_H
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#define DETERMINISTIC_RNG_H
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#include <algorithm>
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#include <cassert>
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#include <cstdint>
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#include <vector>
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#include "nextpnr_namespaces.h"
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NEXTPNR_NAMESPACE_BEGIN
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struct DeterministicRNG
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{
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uint64_t rngstate;
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DeterministicRNG() : rngstate(0x3141592653589793) {}
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uint64_t rng64()
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{
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// xorshift64star
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// https://arxiv.org/abs/1402.6246
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uint64_t retval = rngstate * 0x2545F4914F6CDD1D;
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rngstate ^= rngstate >> 12;
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rngstate ^= rngstate << 25;
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rngstate ^= rngstate >> 27;
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return retval;
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}
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int rng() { return rng64() & 0x3fffffff; }
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int rng(int n)
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{
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assert(n > 0);
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// round up to power of 2
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int m = n - 1;
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m |= (m >> 1);
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m |= (m >> 2);
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m |= (m >> 4);
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m |= (m >> 8);
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m |= (m >> 16);
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m += 1;
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while (1) {
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int x = rng64() & (m - 1);
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if (x < n)
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return x;
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}
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}
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void rngseed(uint64_t seed)
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{
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rngstate = seed ? seed : 0x3141592653589793;
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for (int i = 0; i < 5; i++)
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rng64();
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}
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template <typename Iter> void shuffle(const Iter &begin, const Iter &end)
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{
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std::size_t size = end - begin;
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for (std::size_t i = 0; i != size; i++) {
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std::size_t j = i + rng(size - i);
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if (j > i)
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std::swap(*(begin + i), *(begin + j));
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}
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}
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template <typename T> void shuffle(std::vector<T> &a) { shuffle(a.begin(), a.end()); }
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template <typename T> void sorted_shuffle(std::vector<T> &a)
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{
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std::sort(a.begin(), a.end());
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shuffle(a);
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}
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};
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NEXTPNR_NAMESPACE_END
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#endif
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