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gmp-1.3.2
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mpz_add_ui.c
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1993-05-02
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/* mpz_add_ui -- Add an MP_INT and an unsigned one-word integer.
Copyright (C) 1991 Free Software Foundation, Inc.
This file is part of the GNU MP Library.
The GNU MP Library is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
The GNU MP Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with the GNU MP Library; see the file COPYING. If not, write to
the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
#include "gmp.h"
#include "gmp-impl.h"
void
#ifdef __STDC__
mpz_add_ui (MP_INT *sum, const MP_INT *add1, mp_limb add2)
#else
mpz_add_ui (sum, add1, add2)
MP_INT *sum;
const MP_INT *add1;
mp_limb add2;
#endif
{
mp_srcptr add1p;
mp_ptr sump;
mp_size add1size, sumsize;
mp_size abs_add1size;
add1size = add1->size;
abs_add1size = ABS (add1size);
/* If not space for SUM (and possible carry), increase space. */
sumsize = abs_add1size + 1;
if (sum->alloc < sumsize)
_mpz_realloc (sum, sumsize);
/* These must be after realloc (ADD1 may be the same as SUM). */
add1p = add1->d;
sump = sum->d;
if (add2 == 0)
{
MPN_COPY (sump, add1p, abs_add1size);
sum->size = add1size;
return;
}
if (abs_add1size == 0)
{
sump[0] = add2;
sum->size = 1;
return;
}
if (add1size >= 0)
{
sumsize = mpn_add (sump, add1p, abs_add1size, &add2, 1);
if (sumsize != 0)
sump[abs_add1size] = 1;
sumsize = sumsize + abs_add1size;
}
else
{
/* The signs are different. Need exact comparision to determine
which operand to subtract from which. */
if (abs_add1size == 1 && add1p[0] < add2)
sumsize = (abs_add1size
+ mpn_sub (sump, &add2, 1, add1p, 1));
else
sumsize = -(abs_add1size
+ mpn_sub (sump, add1p, abs_add1size, &add2, 1));
}
sum->size = sumsize;
}