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author | Akira Kakuto <kakuto@fuk.kindai.ac.jp> | 2016-02-22 06:02:38 +0000 |
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committer | Akira Kakuto <kakuto@fuk.kindai.ac.jp> | 2016-02-22 06:02:38 +0000 |
commit | b2ef5d127f546fa32f303b1dedfc4a6390ad677e (patch) | |
tree | 17cd90adb54888579df0e08223bf4909332380c2 /Build/source/libs/mpfr/mpfr-src/src/eq.c | |
parent | 05d739843a7c50294efbda2abf2ab4ea3fc146b1 (diff) |
libs/mpfr: New convention
git-svn-id: svn://tug.org/texlive/trunk@39814 c570f23f-e606-0410-a88d-b1316a301751
Diffstat (limited to 'Build/source/libs/mpfr/mpfr-src/src/eq.c')
-rw-r--r-- | Build/source/libs/mpfr/mpfr-src/src/eq.c | 141 |
1 files changed, 141 insertions, 0 deletions
diff --git a/Build/source/libs/mpfr/mpfr-src/src/eq.c b/Build/source/libs/mpfr/mpfr-src/src/eq.c new file mode 100644 index 00000000000..c58110ca639 --- /dev/null +++ b/Build/source/libs/mpfr/mpfr-src/src/eq.c @@ -0,0 +1,141 @@ +/* mpfr_eq -- Compare two floats up to a specified bit #. + +Copyright 1999, 2001, 2003-2004, 2006-2015 Free Software Foundation, Inc. +Contributed by the AriC and Caramel projects, INRIA. + +This file is part of the GNU MPFR Library. + +The GNU MPFR Library is free software; you can redistribute it and/or modify +it under the terms of the GNU Lesser General Public License as published by +the Free Software Foundation; either version 3 of the License, or (at your +option) any later version. + +The GNU MPFR 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 Lesser General Public +License for more details. + +You should have received a copy of the GNU Lesser General Public License +along with the GNU MPFR Library; see the file COPYING.LESSER. If not, see +http://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc., +51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. */ + + +#include "mpfr-impl.h" + +/* return non-zero if the first n_bits bits of u, v are equal, + 0 otherwise */ +int +mpfr_eq (mpfr_srcptr u, mpfr_srcptr v, unsigned long int n_bits) +{ + mpfr_limb_srcptr up, vp; + mp_size_t usize, vsize, size, i; + mpfr_exp_t uexp, vexp; + int k; + + if (MPFR_ARE_SINGULAR(u, v)) + { + if (MPFR_IS_NAN(u) || MPFR_IS_NAN(v)) + return 0; /* non equal */ + else if (MPFR_IS_INF(u) && MPFR_IS_INF(v)) + return (MPFR_SIGN(u) == MPFR_SIGN(v)); + else if (MPFR_IS_ZERO(u) && MPFR_IS_ZERO(v)) + return 1; + else + return 0; + } + + /* 1. Are the signs different? */ + if (MPFR_SIGN(u) != MPFR_SIGN(v)) + return 0; + + uexp = MPFR_GET_EXP (u); + vexp = MPFR_GET_EXP (v); + + /* 2. Are the exponents different? */ + if (uexp != vexp) + return 0; /* no bit agree */ + + usize = MPFR_LIMB_SIZE (u); + vsize = MPFR_LIMB_SIZE (v); + + if (vsize > usize) /* exchange u and v */ + { + up = MPFR_MANT(v); + vp = MPFR_MANT(u); + size = vsize; + vsize = usize; + usize = size; + } + else + { + up = MPFR_MANT(u); + vp = MPFR_MANT(v); + } + + /* now usize >= vsize */ + MPFR_ASSERTD(usize >= vsize); + + if (usize > vsize) + { + if ((unsigned long) vsize * GMP_NUMB_BITS < n_bits) + { + /* check if low min(PREC(u), n_bits) - (vsize * GMP_NUMB_BITS) + bits from u are non-zero */ + unsigned long remains = n_bits - (vsize * GMP_NUMB_BITS); + k = usize - vsize - 1; + while (k >= 0 && remains >= GMP_NUMB_BITS && !up[k]) + { + k--; + remains -= GMP_NUMB_BITS; + } + /* now either k < 0: all low bits from u are zero + or remains < GMP_NUMB_BITS: check high bits from up[k] + or up[k] <> 0: different */ + if (k >= 0 && (((remains < GMP_NUMB_BITS) && + (up[k] >> (GMP_NUMB_BITS - remains))) || + (remains >= GMP_NUMB_BITS && up[k]))) + return 0; /* surely too different */ + } + size = vsize; + } + else + { + size = usize; + } + + /* now size = min (usize, vsize) */ + + /* If size is too large wrt n_bits, reduce it to look only at the + high n_bits bits. + Otherwise, if n_bits > size * GMP_NUMB_BITS, reduce n_bits to + size * GMP_NUMB_BITS, since the extra low bits of one of the + operands have already been check above. */ + if ((unsigned long) size > 1 + (n_bits - 1) / GMP_NUMB_BITS) + size = 1 + (n_bits - 1) / GMP_NUMB_BITS; + else if (n_bits > (unsigned long) size * GMP_NUMB_BITS) + n_bits = size * GMP_NUMB_BITS; + + up += usize - size; + vp += vsize - size; + + for (i = size - 1; i > 0 && n_bits >= GMP_NUMB_BITS; i--) + { + if (up[i] != vp[i]) + return 0; + n_bits -= GMP_NUMB_BITS; + } + + /* now either i=0 or n_bits<GMP_NUMB_BITS */ + + /* since n_bits <= size * GMP_NUMB_BITS before the above for-loop, + we have the invariant n_bits <= (i+1) * GMP_NUMB_BITS, thus + we always have n_bits <= GMP_NUMB_BITS here */ + MPFR_ASSERTD(n_bits <= GMP_NUMB_BITS); + + if (n_bits & (GMP_NUMB_BITS - 1)) + return (up[i] >> (GMP_NUMB_BITS - (n_bits & (GMP_NUMB_BITS - 1))) == + vp[i] >> (GMP_NUMB_BITS - (n_bits & (GMP_NUMB_BITS - 1)))); + else + return (up[i] == vp[i]); +} |