1 /* mpz_cmp_d -- compare absolute values of mpz and double. 2 3 Copyright 2001, 2002, 2003 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 "config.h" 21 22 #if HAVE_FLOAT_H 23 #include <float.h> /* for DBL_MAX */ 24 #endif 25 26 #include "gmp.h" 27 #include "gmp-impl.h" 28 29 30 #define RETURN_CMP(zl, dl) \ 31 do { \ 32 zlimb = (zl); \ 33 dlimb = (dl); \ 34 if (zlimb != dlimb) \ 35 return (zlimb >= dlimb ? ret : -ret); \ 36 } while (0) 37 38 #define RETURN_NONZERO(ptr, size, val) \ 39 do { \ 40 mp_size_t __i; \ 41 for (__i = (size)-1; __i >= 0; __i--) \ 42 if ((ptr)[__i] != 0) \ 43 return val; \ 44 return 0; \ 45 } while (0) 46 47 48 int 49 mpz_cmp_d (mpz_srcptr z, double d) 50 { 51 mp_limb_t darray[LIMBS_PER_DOUBLE], zlimb, dlimb; 52 mp_srcptr zp; 53 mp_size_t zsize; 54 int dexp, ret; 55 56 /* d=NaN is an invalid operation, there's no sensible return value. 57 d=Inf or -Inf is always bigger than z. */ 58 DOUBLE_NAN_INF_ACTION (d, __gmp_invalid_operation (), goto z_zero); 59 60 /* 1. Either operand zero. */ 61 zsize = SIZ(z); 62 if (d == 0.0) 63 return zsize; 64 if (zsize == 0) 65 { 66 z_zero: 67 return (d < 0.0 ? 1 : -1); 68 } 69 70 /* 2. Opposite signs. */ 71 if (zsize >= 0) 72 { 73 if (d < 0.0) 74 return 1; /* >=0 cmp <0 */ 75 ret = 1; 76 } 77 else 78 { 79 if (d >= 0.0) 80 return -1; /* <0 cmp >=0 */ 81 ret = -1; 82 d = -d; 83 zsize = -zsize; 84 } 85 86 /* 3. Small d, knowing abs(z) >= 1. */ 87 if (d < 1.0) 88 return ret; 89 90 dexp = __gmp_extract_double (darray, d); 91 ASSERT (dexp >= 1); 92 93 /* 4. Check for different high limb positions. */ 94 if (zsize != dexp) 95 return (zsize >= dexp ? ret : -ret); 96 97 /* 5. Limb data. */ 98 zp = PTR(z); 99 100 #if LIMBS_PER_DOUBLE == 2 101 RETURN_CMP (zp[zsize-1], darray[1]); 102 if (zsize == 1) 103 return (darray[0] != 0 ? -ret : 0); 104 105 RETURN_CMP (zp[zsize-2], darray[0]); 106 RETURN_NONZERO (zp, zsize-2, ret); 107 #endif 108 109 #if LIMBS_PER_DOUBLE == 3 110 RETURN_CMP (zp[zsize-1], darray[2]); 111 if (zsize == 1) 112 return ((darray[0] | darray[1]) != 0 ? -ret : 0); 113 114 RETURN_CMP (zp[zsize-2], darray[1]); 115 if (zsize == 2) 116 return (darray[0] != 0 ? -ret : 0); 117 118 RETURN_CMP (zp[zsize-3], darray[0]); 119 RETURN_NONZERO (zp, zsize-3, ret); 120 #endif 121 122 #if LIMBS_PER_DOUBLE >= 4 123 { 124 int i; 125 for (i = 1; i <= LIMBS_PER_DOUBLE; i++) 126 { 127 RETURN_CMP (zp[zsize-i], darray[LIMBS_PER_DOUBLE-i]); 128 if (i >= zsize) 129 RETURN_NONZERO (darray, LIMBS_PER_DOUBLE-i, -ret); 130 } 131 RETURN_NONZERO (zp, zsize-LIMBS_PER_DOUBLE, ret); 132 } 133 #endif 134 } 135