| 1 | /* mpf_cmp_ui -- Compare a float with an unsigned integer. |
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| 2 | |
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| 3 | Copyright 1993, 1994, 1995, 1999, 2001, 2002 Free Software Foundation, Inc. |
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| 4 | |
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| 5 | This file is part of the GNU MP Library. |
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| 6 | |
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| 7 | The GNU MP Library is free software; you can redistribute it and/or modify |
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| 8 | it under the terms of the GNU Lesser General Public License as published by |
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| 9 | the Free Software Foundation; either version 2.1 of the License, or (at your |
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| 10 | option) any later version. |
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| 11 | |
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| 12 | The GNU MP Library is distributed in the hope that it will be useful, but |
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| 13 | WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY |
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| 14 | or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public |
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| 15 | License for more details. |
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| 16 | |
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| 17 | You should have received a copy of the GNU Lesser General Public License |
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| 18 | along with the GNU MP Library; see the file COPYING.LIB. If not, write to |
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| 19 | the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
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| 20 | MA 02111-1307, USA. */ |
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| 21 | |
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| 22 | #include "gmp.h" |
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| 23 | #include "gmp-impl.h" |
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| 24 | |
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| 25 | int |
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| 26 | mpf_cmp_ui (mpf_srcptr u, unsigned long int vval) |
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| 27 | { |
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| 28 | mp_srcptr up; |
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| 29 | mp_size_t usize; |
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| 30 | mp_exp_t uexp; |
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| 31 | mp_limb_t ulimb; |
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| 32 | |
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| 33 | uexp = u->_mp_exp; |
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| 34 | usize = u->_mp_size; |
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| 35 | |
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| 36 | /* 1. Is U negative? */ |
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| 37 | if (usize < 0) |
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| 38 | return -1; |
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| 39 | /* We rely on usize being non-negative in the code that follows. */ |
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| 40 | |
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| 41 | if (vval == 0) |
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| 42 | return usize != 0; |
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| 43 | |
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| 44 | /* 2. Are the exponents different (V's exponent == 1)? */ |
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| 45 | #if GMP_NAIL_BITS != 0 |
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| 46 | if (uexp > 1 + (vval > GMP_NUMB_MAX)) |
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| 47 | return 1; |
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| 48 | if (uexp < 1 + (vval > GMP_NUMB_MAX)) |
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| 49 | return -1; |
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| 50 | #else |
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| 51 | if (uexp > 1) |
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| 52 | return 1; |
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| 53 | if (uexp < 1) |
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| 54 | return -1; |
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| 55 | #endif |
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| 56 | |
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| 57 | up = u->_mp_d; |
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| 58 | |
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| 59 | ulimb = up[usize - 1]; |
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| 60 | #if GMP_NAIL_BITS != 0 |
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| 61 | if (usize >= 2 && uexp == 2) |
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| 62 | { |
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| 63 | if ((ulimb >> GMP_NAIL_BITS) != 0) |
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| 64 | return 1; |
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| 65 | ulimb = (ulimb << GMP_NUMB_BITS) | up[usize - 2]; |
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| 66 | usize--; |
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| 67 | } |
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| 68 | #endif |
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| 69 | usize--; |
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| 70 | |
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| 71 | /* 3. Compare the most significant mantissa limb with V. */ |
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| 72 | if (ulimb > vval) |
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| 73 | return 1; |
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| 74 | else if (ulimb < vval) |
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| 75 | return -1; |
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| 76 | |
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| 77 | /* Ignore zeroes at the low end of U. */ |
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| 78 | while (*up == 0) |
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| 79 | { |
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| 80 | up++; |
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| 81 | usize--; |
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| 82 | } |
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| 83 | |
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| 84 | /* 4. Now, if the number of limbs are different, we have a difference |
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| 85 | since we have made sure the trailing limbs are not zero. */ |
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| 86 | if (usize > 0) |
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| 87 | return 1; |
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| 88 | |
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| 89 | /* Wow, we got zero even if we tried hard to avoid it. */ |
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| 90 | return 0; |
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| 91 | } |
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