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Annotation of OpenXM_contrib/gmp/mpfr/cmp_ui.c, Revision 1.1.1.1

1.1       maekawa     1: /* mpfr_cmp_ui -- compare a floating-point number with a machine integer
                      2:
                      3: Copyright (C) 1999 PolKA project, Inria Lorraine and Loria
                      4:
                      5: This file is part of the MPFR Library.
                      6:
                      7: The MPFR Library is free software; you can redistribute it and/or modify
                      8: it under the terms of the GNU Library General Public License as published by
                      9: the Free Software Foundation; either version 2 of the License, or (at your
                     10: option) any later version.
                     11:
                     12: The MPFR 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 Library General Public
                     15: License for more details.
                     16:
                     17: You should have received a copy of the GNU Library General Public License
                     18: along with the MPFR 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: #include <stdio.h>
                     23: #include "gmp.h"
                     24: #include "gmp-impl.h"
                     25: #include "longlong.h"
                     26: #include "mpfr.h"
                     27:
                     28: /* returns a positive value if b>i*2^f,
                     29:            a negative value if b<i*2^f,
                     30:            zero if b=i*2^f
                     31: */
                     32:
                     33: int
                     34: #if __STDC__
                     35: mpfr_cmp_ui_2exp ( mpfr_srcptr b, unsigned long int i, int f )
                     36: #else
                     37: mpfr_cmp_ui_2exp (b, i, f)
                     38:      mpfr_srcptr b;
                     39:      unsigned long int i;
                     40:      int f;
                     41: #endif
                     42: {
                     43:   int e, k, bn; mp_limb_t c, *bp;
                     44:
                     45:   if (SIGN(b)<0) return -1;
                     46:   else if (!NOTZERO(b)) return((i) ? -1 : 0);
                     47:   else { /* b>0 */
                     48:     e = EXP(b); /* 2^(e-1) <= b < 2^e */
                     49:     if (e>f+mp_bits_per_limb) return 1;
                     50:
                     51:     c = (mp_limb_t) i;
                     52:     count_leading_zeros(k, c);
                     53:     k = f+mp_bits_per_limb - k; /* 2^(k-1) <= i*2^f < 2^k */
                     54:     if (k!=e) return (e-k);
                     55:
                     56:     /* now k=e */
                     57:     c <<= (f+mp_bits_per_limb-k);
                     58:     bn = (PREC(b)-1)/mp_bits_per_limb;
                     59:     bp = MANT(b) + bn;
                     60:     if (*bp>c) return 1;
                     61:     else if (*bp<c) return -1;
                     62:
                     63:     /* most significant limbs agree, check remaining limbs from b */
                     64:     while (--bn>=0)
                     65:       if (*--bp) return 1;
                     66:     return 0;
                     67:   }
                     68: }
                     69:
                     70: /* returns a positive value if b>i*2^f,
                     71:            a negative value if b<i*2^f,
                     72:            zero if b=i*2^f
                     73: */
                     74:
                     75: int
                     76: #if __STDC__
                     77: mpfr_cmp_si_2exp ( mpfr_srcptr b, long int i, int f )
                     78: #else
                     79: mpfr_cmp_si_2exp(b, i, f)
                     80:      mpfr_srcptr b;
                     81:      long int i;
                     82:      int f;
                     83: #endif
                     84: {
                     85:   int e, k, bn, si; mp_limb_t c, *bp;
                     86:
                     87:   si = (i<0) ? -1 : 1; /* sign of i */
                     88:   if (SIGN(b)*i<0) return SIGN(b); /* both signs differ */
                     89:   else if (!NOTZERO(b) || (i==0)) { /* one is zero */
                     90:     if (i==0) return ((NOTZERO(b)) ? SIGN(b) : 0);
                     91:     else return si; /* b is zero */
                     92:
                     93:   }
                     94:   else { /* b and i are of same sign */
                     95:     e = EXP(b); /* 2^(e-1) <= b < 2^e */
                     96:     if (e>f+mp_bits_per_limb) return si;
                     97:
                     98:     c = (mp_limb_t) ((i<0) ? -i : i);
                     99:     count_leading_zeros(k, c);
                    100:     k = f+mp_bits_per_limb - k; /* 2^(k-1) <= i*2^f < 2^k */
                    101:     if (k!=e) return (si*(e-k));
                    102:
                    103:     /* now k=e */
                    104:     c <<= (f+mp_bits_per_limb-k);
                    105:     bn = (PREC(b)-1)/mp_bits_per_limb;
                    106:     bp = MANT(b) + bn;
                    107:     if (*bp>c) return si;
                    108:     else if (*bp<c) return -si;
                    109:
                    110:     /* most significant limbs agree, check remaining limbs from b */
                    111:     while (--bn>=0)
                    112:       if (*--bp) return si;
                    113:     return 0;
                    114:   }
                    115: }
                    116: