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/*
Copyright (C) 2014 Fredrik Johansson
This file is part of FLINT.
FLINT is free software: you can redistribute it and/or modify it under
the terms of the GNU Lesser General Public License (LGPL) as published
by the Free Software Foundation; either version 3 of the License, or
(at your option) any later version. See <https://www.gnu.org/licenses/>.
*/
#include "longlong.h"
#include "mag.h"
void
mag_set_ui_2exp_si(mag_t z, ulong x, slong e)
{
_fmpz_demote(MAG_EXPREF(z));
if (x == 0)
{
MAG_EXP(z) = 0;
MAG_MAN(z) = 0;
}
else
{
slong bits;
ulong overflow;
bits = flint_clz(x);
bits = FLINT_BITS - bits;
if (bits <= MAG_BITS)
{
x = x << (MAG_BITS - bits);
}
else
{
x = (x >> (bits - MAG_BITS)) + 1;
overflow = x >> MAG_BITS;
bits += overflow;
x >>= overflow;
}
if (e >= MAG_MIN_LAGOM_EXP && e <= MAG_MAX_LAGOM_EXP)
{
MAG_EXP(z) = bits + e;
}
else
{
fmpz_set_si(MAG_EXPREF(z), e);
fmpz_add_si(MAG_EXPREF(z), MAG_EXPREF(z), bits);
}
MAG_MAN(z) = x;
}
}