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/*
* nextpnr -- Next Generation Place and Route
*
* Copyright (c) 2013 Mike Pedersen
* 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.
*
*/
#include "bits.h"
#include <limits>
#include <stdexcept>
namespace nextpnr {
int Bits::generic_popcount(unsigned int v)
{
unsigned int c; // c accumulates the total bits set in v
for (c = 0; v; c++) {
v &= v - 1; // clear the least significant bit set
}
return c;
}
int Bits::generic_ctz(unsigned int x)
{
if (x == 0) {
throw std::runtime_error("Cannot call ctz with arg = 0");
}
for (size_t i = 0; i < std::numeric_limits<unsigned int>::digits; ++i) {
if ((x & (1 << i)) != 0) {
return i;
}
}
// Unreachable!
throw std::runtime_error("Unreachable!");
}
}; // namespace nextpnr
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