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/* mpf_cmp_si -- Compare a float with a signed integer.
Copyright 1993-1995, 1999-2002, 2004, 2012 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 Lesser General Public License as published
by the Free Software Foundation; either version 3 of the License, 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 Lesser General Public
License for more details.
You should have received a copy of the GNU Lesser General Public License
along with the GNU MP Library. If not, see https://www.gnu.org/licenses/. */
#include "gmp.h"
#include "gmp-impl.h"
int
mpf_cmp_si (mpf_srcptr u, long int vval) __GMP_NOTHROW
{
mp_srcptr up;
mp_size_t usize;
mp_exp_t uexp;
mp_limb_t ulimb;
int usign;
unsigned long abs_vval;
uexp = u->_mp_exp;
usize = u->_mp_size;
/* 1. Are the signs different? */
if ((usize < 0) == (vval < 0)) /* don't use xor, type size may differ */
{
/* U and V are both non-negative or both negative. */
if (usize == 0)
/* vval >= 0 */
return -(vval != 0);
if (vval == 0)
/* usize >= 0 */
return usize != 0;
/* Fall out. */
}
else
{
/* Either U or V is negative, but not both. */
return usize >= 0 ? 1 : -1;
}
/* U and V have the same sign and are both non-zero. */
usign = usize >= 0 ? 1 : -1;
usize = ABS (usize);
abs_vval = ABS_CAST (unsigned long, vval);
/* 2. Are the exponents different (V's exponent == 1)? */
#if GMP_NAIL_BITS != 0
if (uexp > 1 + (abs_vval > GMP_NUMB_MAX))
return usign;
if (uexp < 1 + (abs_vval > GMP_NUMB_MAX))
return -usign;
#else
if (uexp > 1)
return usign;
if (uexp < 1)
return -usign;
#endif
up = u->_mp_d;
ulimb = up[usize - 1];
#if GMP_NAIL_BITS != 0
if (usize >= 2 && uexp == 2)
{
if ((ulimb >> GMP_NAIL_BITS) != 0)
return usign;
ulimb = (ulimb << GMP_NUMB_BITS) | up[usize - 2];
usize--;
}
#endif
usize--;
/* 3. Compare the most significant mantissa limb with V. */
if (ulimb > abs_vval)
return usign;
else if (ulimb < abs_vval)
return -usign;
/* Ignore zeroes at the low end of U. */
while (*up == 0)
{
up++;
usize--;
}
/* 4. Now, if the number of limbs are different, we have a difference
since we have made sure the trailing limbs are not zero. */
if (usize > 0)
return usign;
/* Wow, we got zero even if we tried hard to avoid it. */
return 0;
}
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