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