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/*
Copyright (C) 2014 Fredrik Johansson
This file is part of Arb.
Arb 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 2.1 of the License, or
(at your option) any later version. See <http://www.gnu.org/licenses/>.
*/
#include "mag.h"
void
mag_add(mag_t z, const mag_t x, const mag_t y)
{
if (mag_is_zero(x))
{
mag_set(z, y);
}
else if (mag_is_zero(y))
{
mag_set(z, x);
}
else if (mag_is_inf(x) || mag_is_inf(y))
{
mag_inf(z);
}
else
{
slong shift;
shift = _fmpz_sub_small(MAG_EXPREF(x), MAG_EXPREF(y));
if (shift == 0)
{
_fmpz_set_fast(MAG_EXPREF(z), MAG_EXPREF(x));
MAG_MAN(z) = MAG_MAN(x) + MAG_MAN(y);
MAG_ADJUST_ONE_TOO_LARGE(z); /* may need two adjustments */
}
else if (shift > 0)
{
_fmpz_set_fast(MAG_EXPREF(z), MAG_EXPREF(x));
if (shift >= MAG_BITS)
MAG_MAN(z) = MAG_MAN(x) + LIMB_ONE;
else
MAG_MAN(z) = MAG_MAN(x) + (MAG_MAN(y) >> shift) + LIMB_ONE;
}
else
{
shift = -shift;
_fmpz_set_fast(MAG_EXPREF(z), MAG_EXPREF(y));
if (shift >= MAG_BITS)
MAG_MAN(z) = MAG_MAN(y) + LIMB_ONE;
else
MAG_MAN(z) = MAG_MAN(y) + (MAG_MAN(x) >> shift) + LIMB_ONE;
}
/* TODO: combine */
MAG_ADJUST_ONE_TOO_LARGE(z);
}
}
void
mag_add_lower(mag_t z, const mag_t x, const mag_t y)
{
if (mag_is_zero(x))
{
mag_set(z, y);
}
else if (mag_is_zero(y))
{
mag_set(z, x);
}
else if (mag_is_inf(x) || mag_is_inf(y))
{
mag_inf(z);
}
else
{
slong shift;
shift = _fmpz_sub_small(MAG_EXPREF(x), MAG_EXPREF(y));
if (shift == 0)
{
_fmpz_set_fast(MAG_EXPREF(z), MAG_EXPREF(x));
MAG_MAN(z) = MAG_MAN(x) + MAG_MAN(y);
}
else if (shift > 0)
{
_fmpz_set_fast(MAG_EXPREF(z), MAG_EXPREF(x));
if (shift >= MAG_BITS)
MAG_MAN(z) = MAG_MAN(x);
else
MAG_MAN(z) = MAG_MAN(x) + (MAG_MAN(y) >> shift);
}
else
{
shift = -shift;
_fmpz_set_fast(MAG_EXPREF(z), MAG_EXPREF(y));
if (shift >= MAG_BITS)
MAG_MAN(z) = MAG_MAN(y);
else
MAG_MAN(z) = MAG_MAN(y) + (MAG_MAN(x) >> shift);
}
if (MAG_MAN(z) >> MAG_BITS)
{
MAG_MAN(z) >>= 1;
_fmpz_add_fast(MAG_EXPREF(z), MAG_EXPREF(z), 1);
}
}
}
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