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