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Diffstat (limited to 'gnu/lib/libgmp/mpf/eq.c')
-rw-r--r-- | gnu/lib/libgmp/mpf/eq.c | 121 |
1 files changed, 121 insertions, 0 deletions
diff --git a/gnu/lib/libgmp/mpf/eq.c b/gnu/lib/libgmp/mpf/eq.c new file mode 100644 index 00000000000..e6630ad6e9f --- /dev/null +++ b/gnu/lib/libgmp/mpf/eq.c @@ -0,0 +1,121 @@ +/* mpf_eq -- Compare two floats up to a specified bit #. + +Copyright (C) 1993, 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" + +int +#if __STDC__ +mpf_eq (mpf_srcptr u, mpf_srcptr v, unsigned long int n_bits) +#else +mpf_eq (u, v, n_bits) + mpf_srcptr u; + mpf_srcptr v; + unsigned long int n_bits; +#endif +{ + mp_srcptr up, vp; + mp_size_t usize, vsize, size, i; + mp_exp_t uexp, vexp; + int usign; + + uexp = u->_mp_exp; + vexp = v->_mp_exp; + + usize = u->_mp_size; + vsize = v->_mp_size; + + /* 1. Are the signs different? */ + if ((usize ^ vsize) >= 0) + { + /* U and V are both non-negative or both negative. */ + if (usize == 0) + return vsize == 0; + if (vsize == 0) + return 0; + + /* Fall out. */ + } + else + { + /* Either U or V is negative, but not both. */ + return 0; + } + + /* U and V have the same sign and are both non-zero. */ + + usign = usize >= 0 ? 1 : -1; + + /* 2. Are the exponents different? */ + if (uexp > vexp) + return 0; /* ??? handle (uexp = vexp + 1) */ + if (vexp > uexp) + return 0; /* ??? handle (vexp = uexp + 1) */ + + usize = ABS (usize); + vsize = ABS (vsize); + + up = u->_mp_d; + vp = v->_mp_d; + + /* Ignore zeroes at the low end of U and V. */ + while (up[0] == 0) + { + up++; + usize--; + } + while (vp[0] == 0) + { + vp++; + vsize--; + } + + if (usize > vsize) + { + if (vsize * BITS_PER_MP_LIMB < n_bits) + return 0; /* surely too different */ + size = vsize; + } + else if (vsize > usize) + { + if (usize * BITS_PER_MP_LIMB < n_bits) + return 0; /* surely too different */ + size = usize; + } + else + { + size = usize; + } + + if (size > (n_bits + BITS_PER_MP_LIMB - 1) / BITS_PER_MP_LIMB) + size = (n_bits + BITS_PER_MP_LIMB - 1) / BITS_PER_MP_LIMB; + + up += usize - size; + vp += vsize - size; + + for (i = size - 1; i >= 0; i--) + { + if (up[i] != vp[i]) + return 0; + } + + return 1; +} |