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Diffstat (limited to 'gnu/lib/libgmp/mpq/add.c')
-rw-r--r-- | gnu/lib/libgmp/mpq/add.c | 85 |
1 files changed, 85 insertions, 0 deletions
diff --git a/gnu/lib/libgmp/mpq/add.c b/gnu/lib/libgmp/mpq/add.c new file mode 100644 index 0000000..6b98b46 --- /dev/null +++ b/gnu/lib/libgmp/mpq/add.c @@ -0,0 +1,85 @@ +/* mpq_add -- add two rational numbers. + +Copyright (C) 1991, 1994, 1995, 1996 Free Software Foundation, Inc. + +This file is part of the GNU MP Library. + +The GNU MP Library is free software; you can redistribute it and/or modify +it under the terms of the GNU Library General Public License as published by +the Free Software Foundation; either version 2 of the License, or (at your +option) any later version. + +The GNU MP Library is distributed in the hope that it will be useful, but +WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY +or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public +License for more details. + +You should have received a copy of the GNU Library General Public License +along with the GNU MP Library; see the file COPYING.LIB. If not, write to +the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, +MA 02111-1307, USA. */ + +#include "gmp.h" +#include "gmp-impl.h" + +void +#if __STDC__ +mpq_add (mpq_ptr rop, mpq_srcptr op1, mpq_srcptr op2) +#else +mpq_add (rop, op1, op2) + mpq_ptr rop; + mpq_srcptr op1; + mpq_srcptr op2; +#endif +{ + mpz_t gcd; + mpz_t tmp1, tmp2; + mp_size_t op1_num_size = ABS (op1->_mp_num._mp_size); + mp_size_t op1_den_size = ABS (op1->_mp_den._mp_size); + mp_size_t op2_num_size = ABS (op2->_mp_num._mp_size); + mp_size_t op2_den_size = ABS (op2->_mp_den._mp_size); + TMP_DECL (marker); + + TMP_MARK (marker); + MPZ_TMP_INIT (gcd, MIN (op1_den_size, op2_den_size)); + MPZ_TMP_INIT (tmp1, op1_num_size + op2_den_size); + MPZ_TMP_INIT (tmp2, op2_num_size + op1_den_size); + + /* ROP might be identical to either operand, so don't store the + result there until we are finished with the input operands. We + dare to overwrite the numerator of ROP when we are finished + with the numerators of OP1 and OP2. */ + + mpz_gcd (gcd, &(op1->_mp_den), &(op2->_mp_den)); + if (gcd->_mp_size > 1 || gcd->_mp_d[0] != 1) + { + mpz_t t; + + mpz_divexact (tmp1, &(op2->_mp_den), gcd); + mpz_mul (tmp1, &(op1->_mp_num), tmp1); + + mpz_divexact (tmp2, &(op1->_mp_den), gcd); + mpz_mul (tmp2, &(op2->_mp_num), tmp2); + + MPZ_TMP_INIT (t, MAX (ABS (tmp1->_mp_size), ABS (tmp2->_mp_size)) + 1); + + mpz_add (t, tmp1, tmp2); + mpz_divexact (tmp1, &(op1->_mp_den), gcd); + mpz_gcd (gcd, t, gcd); + + mpz_divexact (&(rop->_mp_num), t, gcd); + + mpz_divexact (tmp2, &(op2->_mp_den), gcd); + mpz_mul (&(rop->_mp_den), tmp1, tmp2); + } + else + { + /* The common divisor is 1. This is the case (for random input) with + probability 6/(pi**2). */ + mpz_mul (tmp1, &(op1->_mp_num), &(op2->_mp_den)); + mpz_mul (tmp2, &(op2->_mp_num), &(op1->_mp_den)); + mpz_add (&(rop->_mp_num), tmp1, tmp2); + mpz_mul (&(rop->_mp_den), &(op1->_mp_den), &(op2->_mp_den)); + } + TMP_FREE (marker); +} |