92 lines
2.4 KiB
C
92 lines
2.4 KiB
C
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/* mpf_cmp_ui -- Compare a float with an unsigned integer.
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Copyright 1993, 1994, 1995, 1999, 2001, 2002 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 Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 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 Lesser General Public
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License for more details.
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You should have received a copy of the GNU Lesser 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., 51 Franklin Street, Fifth Floor, Boston,
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MA 02110-1301, 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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mpf_cmp_ui (mpf_srcptr u, unsigned long int vval)
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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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mp_limb_t ulimb;
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uexp = u->_mp_exp;
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usize = u->_mp_size;
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/* 1. Is U negative? */
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if (usize < 0)
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return -1;
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/* We rely on usize being non-negative in the code that follows. */
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if (vval == 0)
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return usize != 0;
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/* 2. Are the exponents different (V's exponent == 1)? */
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#if GMP_NAIL_BITS != 0
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if (uexp > 1 + (vval > GMP_NUMB_MAX))
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return 1;
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if (uexp < 1 + (vval > GMP_NUMB_MAX))
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return -1;
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#else
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if (uexp > 1)
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return 1;
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if (uexp < 1)
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return -1;
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#endif
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up = u->_mp_d;
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ulimb = up[usize - 1];
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#if GMP_NAIL_BITS != 0
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if (usize >= 2 && uexp == 2)
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{
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if ((ulimb >> GMP_NAIL_BITS) != 0)
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return 1;
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ulimb = (ulimb << GMP_NUMB_BITS) | up[usize - 2];
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usize--;
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}
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#endif
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usize--;
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/* 3. Compare the most significant mantissa limb with V. */
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if (ulimb > vval)
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return 1;
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else if (ulimb < vval)
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return -1;
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/* Ignore zeroes at the low end of U. */
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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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/* 4. 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 > 0)
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return 1;
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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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