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Diffstat (limited to 'mpf/cmp.c')
-rw-r--r-- | mpf/cmp.c | 114 |
1 files changed, 114 insertions, 0 deletions
diff --git a/mpf/cmp.c b/mpf/cmp.c new file mode 100644 index 000000000..d440e1152 --- /dev/null +++ b/mpf/cmp.c @@ -0,0 +1,114 @@ +/* mpf_cmp -- Compare two floats. + +Copyright (C) 1993, 1994, 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_cmp (mpf_srcptr u, mpf_srcptr v) +#else +mpf_cmp (u, v) + mpf_srcptr u; + mpf_srcptr v; +#endif +{ + mp_srcptr up, vp; + mp_size_t usize, vsize; + mp_exp_t uexp, vexp; + int cmp; + 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) + /* vsize >= 0 */ + return -(vsize != 0); + if (vsize == 0) + /* usize >= 0 */ + return usize != 0; + /* Fall out. */ + } + else + { + /* Either U or V is negative, but not both. */ + return usize >= 0 ? 1 : -1; + } + + /* 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 usign; + if (uexp < vexp) + return -usign; + + usize = ABS (usize); + vsize = ABS (vsize); + + up = u->_mp_d; + vp = v->_mp_d; + +#define STRICT_MPF_NORMALIZATION 0 +#if ! STRICT_MPF_NORMALIZATION + /* Ignore zeroes at the low end of U and V. */ + while (up[0] == 0) + { + up++; + usize--; + } + while (vp[0] == 0) + { + vp++; + vsize--; + } +#endif + + if (usize > vsize) + { + cmp = mpn_cmp (up + usize - vsize, vp, vsize); + if (cmp == 0) + return usign; + } + else if (vsize > usize) + { + cmp = mpn_cmp (up, vp + vsize - usize, usize); + if (cmp == 0) + return -usign; + } + else + { + cmp = mpn_cmp (up, vp, usize); + if (cmp == 0) + return 0; + } + return cmp > 0 ? usign : -usign; +} |