1 /* mpz_get_si(integer) -- Return the least significant digit from INTEGER. 2 3 Copyright 1991, 1993, 1994, 1995, 2000, 2001, 2002, 2006 Free Software 4 Foundation, 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 "gmp.h" 22 #include "gmp-impl.h" 23 24 signed long int 25 mpz_get_si (mpz_srcptr z) __GMP_NOTHROW 26 { 27 mp_ptr zp = z->_mp_d; 28 mp_size_t size = z->_mp_size; 29 mp_limb_t zl = zp[0]; 30 31 #if GMP_NAIL_BITS != 0 32 if (ULONG_MAX > GMP_NUMB_MAX && ABS (size) >= 2) 33 zl |= zp[1] << GMP_NUMB_BITS; 34 #endif 35 36 if (size > 0) 37 return zl & LONG_MAX; 38 else if (size < 0) 39 /* This expression is necessary to properly handle 0x80000000 */ 40 return -1 - (long) ((zl - 1) & LONG_MAX); 41 else 42 return 0; 43 } 44