1 /* mpz_sqrtrem(root,rem,x) -- Set ROOT to floor(sqrt(X)) and REM 2 to the remainder, i.e. X - ROOT**2. 3 4 Copyright 1991, 1993, 1994, 1996, 2000, 2001, 2005 Free Software Foundation, 5 Inc. 6 7 This file is part of the GNU MP Library. 8 9 The GNU MP Library is free software; you can redistribute it and/or modify 10 it under the terms of the GNU Lesser General Public License as published by 11 the Free Software Foundation; either version 3 of the License, or (at your 12 option) any later version. 13 14 The GNU MP Library is distributed in the hope that it will be useful, but 15 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 16 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public 17 License for more details. 18 19 You should have received a copy of the GNU Lesser General Public License 20 along with the GNU MP Library. If not, see http://www.gnu.org/licenses/. */ 21 22 #include <stdio.h> /* for NULL */ 23 #include "gmp.h" 24 #include "gmp-impl.h" 25 #ifdef BERKELEY_MP 26 #include "mp.h" 27 #endif 28 29 void 30 #ifndef BERKELEY_MP 31 mpz_sqrtrem (mpz_ptr root, mpz_ptr rem, mpz_srcptr op) 32 #else /* BERKELEY_MP */ 33 msqrt (mpz_srcptr op, mpz_ptr root, mpz_ptr rem) 34 #endif /* BERKELEY_MP */ 35 { 36 mp_size_t op_size, root_size, rem_size; 37 mp_ptr root_ptr, op_ptr; 38 mp_ptr free_me = NULL; 39 mp_size_t free_me_size; 40 TMP_DECL; 41 42 TMP_MARK; 43 op_size = op->_mp_size; 44 if (op_size <= 0) 45 { 46 if (op_size < 0) 47 SQRT_OF_NEGATIVE; 48 SIZ(root) = 0; 49 SIZ(rem) = 0; 50 return; 51 } 52 53 if (rem->_mp_alloc < op_size) 54 _mpz_realloc (rem, op_size); 55 56 /* The size of the root is accurate after this simple calculation. */ 57 root_size = (op_size + 1) / 2; 58 59 root_ptr = root->_mp_d; 60 op_ptr = op->_mp_d; 61 62 if (root->_mp_alloc < root_size) 63 { 64 if (root_ptr == op_ptr) 65 { 66 free_me = root_ptr; 67 free_me_size = root->_mp_alloc; 68 } 69 else 70 (*__gmp_free_func) (root_ptr, root->_mp_alloc * BYTES_PER_MP_LIMB); 71 72 root->_mp_alloc = root_size; 73 root_ptr = (mp_ptr) (*__gmp_allocate_func) (root_size * BYTES_PER_MP_LIMB); 74 root->_mp_d = root_ptr; 75 } 76 else 77 { 78 /* Make OP not overlap with ROOT. */ 79 if (root_ptr == op_ptr) 80 { 81 /* ROOT and OP are identical. Allocate temporary space for OP. */ 82 op_ptr = TMP_ALLOC_LIMBS (op_size); 83 /* Copy to the temporary space. Hack: Avoid temporary variable 84 by using ROOT_PTR. */ 85 MPN_COPY (op_ptr, root_ptr, op_size); 86 } 87 } 88 89 rem_size = mpn_sqrtrem (root_ptr, rem->_mp_d, op_ptr, op_size); 90 91 root->_mp_size = root_size; 92 93 /* Write remainder size last, to enable us to define this function to 94 give only the square root remainder, if the user calls if with 95 ROOT == REM. */ 96 rem->_mp_size = rem_size; 97 98 if (free_me != NULL) 99 (*__gmp_free_func) (free_me, free_me_size * BYTES_PER_MP_LIMB); 100 TMP_FREE; 101 } 102