99 lines
2.4 KiB
C
99 lines
2.4 KiB
C
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/* mpf_cmp_si -- Compare a float with a signed integer.
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Copyright (C) 1993, 1994, 1995 Free Software Foundation, Inc.
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This file is part of the GNU MP Library.
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The GNU MP Library is free software; you can redistribute it and/or modify
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it under the terms of the GNU Library General Public License as published by
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the Free Software Foundation; either version 2 of the License, or (at your
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option) any later version.
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The GNU MP Library is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public
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License for more details.
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You should have received a copy of the GNU Library General Public License
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along with the GNU MP Library; see the file COPYING.LIB. If not, write to
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the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
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MA 02111-1307, USA. */
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#include "gmp.h"
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#include "gmp-impl.h"
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int
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#if __STDC__
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mpf_cmp_si (mpf_srcptr u, long int vslimb)
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#else
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mpf_cmp_si (u, vslimb)
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mpf_srcptr u;
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long int vslimb;
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#endif
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{
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mp_srcptr up;
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mp_size_t usize;
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mp_exp_t uexp;
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int usign;
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uexp = u->_mp_exp;
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usize = u->_mp_size;
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/* 1. Are the signs different? */
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if ((usize < 0) == (vslimb < 0)) /* don't use xor, type size may differ */
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{
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/* U and V are both non-negative or both negative. */
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if (usize == 0)
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/* vslimb >= 0 */
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return -(vslimb != 0);
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if (vslimb == 0)
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/* usize >= 0 */
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return usize != 0;
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/* Fall out. */
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}
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else
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{
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/* Either U or V is negative, but not both. */
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return usize >= 0 ? 1 : -1;
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}
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/* U and V have the same sign and are both non-zero. */
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usign = usize >= 0 ? 1 : -1;
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/* 2. Are the exponents different (V's exponent == 1)? */
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if (uexp > 1)
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return usign;
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if (uexp < 1)
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return -usign;
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usize = ABS (usize);
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vslimb = ABS (vslimb);
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up = u->_mp_d;
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#define STRICT_MPF_NORMALIZATION 0
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#if ! STRICT_MPF_NORMALIZATION
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/* Ignore zeroes at the low end of U and V. */
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while (*up == 0)
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{
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up++;
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usize--;
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}
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#endif
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/* 3. Now, if the number of limbs are different, we have a difference
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since we have made sure the trailing limbs are not zero. */
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if (usize > 1)
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return usign;
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/* 4. Compare the mantissas. */
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if (*up > vslimb)
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return usign;
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else if (*up < vslimb)
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return -usign;
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/* Wow, we got zero even if we tried hard to avoid it. */
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return 0;
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}
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