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Annotation of OpenXM_contrib/gmp/mpz/cmpabs_d.c, Revision 1.1.1.1

1.1       ohara       1: /* mpz_cmpabs_d -- compare absolute values of mpz and double.
                      2:
                      3: Copyright 2001, 2002 Free Software Foundation, Inc.
                      4:
                      5: This file is part of the GNU MP Library.
                      6:
                      7: The GNU MP Library is free software; you can redistribute it and/or modify
                      8: it under the terms of the GNU Lesser General Public License as published by
                      9: the Free Software Foundation; either version 2.1 of the License, or (at your
                     10: option) any later version.
                     11:
                     12: The GNU MP Library is distributed in the hope that it will be useful, but
                     13: WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
                     14: or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
                     15: License for more details.
                     16:
                     17: You should have received a copy of the GNU Lesser General Public License
                     18: along with the GNU MP Library; see the file COPYING.LIB.  If not, write to
                     19: the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
                     20: MA 02111-1307, USA.
                     21: */
                     22:
                     23: #include "gmp.h"
                     24: #include "gmp-impl.h"
                     25:
                     26:
                     27: #define RETURN_CMP(zl, dl)              \
                     28:   do {                                  \
                     29:     zlimb = (zl);                       \
                     30:     dlimb = (dl);                       \
                     31:     if (zlimb != dlimb)                 \
                     32:       return (zlimb >= dlimb ? 1 : -1); \
                     33:   } while (0)
                     34:
                     35: #define RETURN_NONZERO(ptr, size, val)          \
                     36:   do {                                          \
                     37:     mp_size_t __i;                              \
                     38:     for (__i = (size)-1; __i >= 0; __i--)       \
                     39:       if ((ptr)[__i] != 0)                      \
                     40:         return val;                             \
                     41:     return 0;                                   \
                     42:   } while (0)
                     43:
                     44:
                     45: int
                     46: mpz_cmpabs_d (mpz_srcptr z, double d)
                     47: {
                     48:   mp_limb_t  darray[LIMBS_PER_DOUBLE], zlimb, dlimb;
                     49:   mp_srcptr  zp;
                     50:   mp_size_t  zsize;
                     51:   int        dexp;
                     52:
                     53:   /* 1. Check for either operand zero. */
                     54:   zsize = SIZ(z);
                     55:   if (d == 0.0)
                     56:     return (zsize != 0);
                     57:   if (zsize == 0)
                     58:     return (d != 0 ? -1 : 0);
                     59:
                     60:   /* 2. Ignore signs. */
                     61:   zsize = ABS(zsize);
                     62:   d = ABS(d);
                     63:
                     64:   /* 3. Small d, knowing abs(z) >= 1. */
                     65:   if (d < 1.0)
                     66:     return 1;
                     67:
                     68:   dexp = __gmp_extract_double (darray, d);
                     69:   ASSERT (dexp >= 1);
                     70:
                     71:   /* 4. Check for different high limb positions. */
                     72:   if (zsize != dexp)
                     73:     return (zsize >= dexp ? 1 : -1);
                     74:
                     75:   /* 5. Limb data. */
                     76:   zp = PTR(z);
                     77:
                     78: #if LIMBS_PER_DOUBLE == 2
                     79:   RETURN_CMP (zp[zsize-1], darray[1]);
                     80:   if (zsize == 1)
                     81:     return (darray[0] != 0 ? -1 : 0);
                     82:
                     83:   RETURN_CMP (zp[zsize-2], darray[0]);
                     84:   RETURN_NONZERO (zp, zsize-2, 1);
                     85:
                     86: #else
                     87: #if LIMBS_PER_DOUBLE == 3
                     88:   RETURN_CMP (zp[zsize-1], darray[2]);
                     89:   if (zsize == 1)
                     90:     return ((darray[0] | darray[1]) != 0 ? -1 : 0);
                     91:
                     92:   RETURN_CMP (zp[zsize-2], darray[1]);
                     93:   if (zsize == 2)
                     94:     return (darray[0] != 0 ? -1 : 0);
                     95:
                     96:   RETURN_CMP (zp[zsize-3], darray[0]);
                     97:   RETURN_NONZERO (zp, zsize-3, 1);
                     98:
                     99: #else
                    100:   for (i = 1; i <= LIMBS_PER_DOUBLE; i++)
                    101:     {
                    102:       RETURN_CMP (zp[zsize-i], darray[LIMBS_PER_DOUBLE-i]);
                    103:       if (i >= zsize)
                    104:         RETURN_NONZERO (darray, LIMBS_PER_DOUBLE-i, -1);
                    105:     }
                    106:   RETURN_NONZERO (zp, zsize-LIMBS_PER_DOUBLE, 1);
                    107: #endif
                    108: #endif
                    109: }