[BACK]Return to set_z.c CVS log [TXT][DIR] Up to [local] / OpenXM_contrib / gmp / mpfr

Diff for /OpenXM_contrib/gmp/mpfr/Attic/set_z.c between version 1.1.1.1 and 1.1.1.2

version 1.1.1.1, 2000/09/09 14:12:19 version 1.1.1.2, 2003/08/25 16:06:07
Line 1 
Line 1 
 /* mpfr_set_z -- set a floating-point number from a multiple-precision integer  /* mpfr_set_z -- set a floating-point number from a multiple-precision integer
   
 Copyright (C) 1999 PolKA project, Inria Lorraine and Loria  Copyright 1999, 2000, 2001, 2002 Free Software Foundation, Inc.
   
 This file is part of the MPFR Library.  This file is part of the MPFR Library.
   
 The MPFR Library is free software; you can redistribute it and/or modify  The MPFR 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  it under the terms of the GNU Lesser General Public License as published by
 the Free Software Foundation; either version 2 of the License, or (at your  the Free Software Foundation; either version 2.1 of the License, or (at your
 option) any later version.  option) any later version.
   
 The MPFR Library is distributed in the hope that it will be useful, but  The MPFR Library is distributed in the hope that it will be useful, but
 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY  WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Library General Public  or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
 License for more details.  License for more details.
   
 You should have received a copy of the GNU Library General Public License  You should have received a copy of the GNU Lesser General Public License
 along with the MPFR Library; see the file COPYING.LIB.  If not, write to  along with the MPFR Library; see the file COPYING.LIB.  If not, write to
 the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,  the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
 MA 02111-1307, USA. */  MA 02111-1307, USA. */
Line 23  MA 02111-1307, USA. */
Line 23  MA 02111-1307, USA. */
 #include "gmp-impl.h"  #include "gmp-impl.h"
 #include "longlong.h"  #include "longlong.h"
 #include "mpfr.h"  #include "mpfr.h"
   #include "mpfr-impl.h"
   
 /* set f to the integer z */  /* set f to the integer z */
 int  int
 #if __STDC__  mpfr_set_z (mpfr_ptr f, mpz_srcptr z, mp_rnd_t rnd_mode)
 mpfr_set_z (mpfr_ptr f, mpz_srcptr z, unsigned char rnd)  
 #else  
 mpfr_set_z (f, z, rnd)  
      mpfr_ptr f;  
      mpz_srcptr z;  
      unsigned char rnd;  
 #endif  
 {  {
   int fn, zn, k, dif, sign_z, sh; mp_limb_t *fp = MANT(f), *zp, cc, c2;    mp_size_t fn, zn, dif;
     int k, sign_z, inex;
     mp_limb_t *fp, *zp;
     mp_exp_t exp;
   
   sign_z = mpz_cmp_ui(z,0);    MPFR_CLEAR_FLAGS (f); /* z cannot be NaN nor Inf */
   if (sign_z==0) return (SIZE(f)=0);  
   fn = 1 + (PREC(f)-1)/BITS_PER_MP_LIMB;    sign_z = mpz_cmp_ui (z, 0);
   
     if (sign_z == 0)
       {
         MPFR_SET_ZERO(f);
         MPFR_SET_POS(f);
         MPFR_RET(0);
       }
   
     fp = MPFR_MANT(f);
     fn = 1 + (MPFR_PREC(f) - 1) / BITS_PER_MP_LIMB;
   zn = ABS(SIZ(z));    zn = ABS(SIZ(z));
   dif = zn-fn;    dif = zn - fn;
   zp = PTR(z);    zp = PTR(z);
   count_leading_zeros(k, zp[zn-1]);    count_leading_zeros(k, zp[zn-1]);
   EXP(f) = zn*BITS_PER_MP_LIMB-k;  
   if (SIGN(f)*sign_z<0) CHANGE_SIGN(f);  
   if (dif>=0) { /* number has to be truncated */  
     if (k) {  
       mpn_lshift(fp, zp + dif, fn, k);  
       if (dif) *fp += zp[dif-1] >> (BITS_PER_MP_LIMB-k);  
     }  
     else MPN_COPY(fp, zp + dif, fn);  
     sh = fn*BITS_PER_MP_LIMB-PREC(f);  
     cc = *fp & (((mp_limb_t)1 << sh) - 1);  
     *fp = *fp & ~cc;  
     if (rnd==GMP_RNDN) {  
       if (sh) c2 = (mp_limb_t)1 << (sh-1);  
       else { /* sh=0 */  
         c2 = ((mp_limb_t)1) << (BITS_PER_MP_LIMB-1);  
         dif--;  
         cc = (dif>=0) ? ((zp[dif])<<k) : 0;  
         if (dif>0 && k) cc += zp[dif-1] >> (BITS_PER_MP_LIMB-k);  
       }  
       /* now compares cc to c2 */  
       if (cc>c2) { mpfr_add_one_ulp(f); return cc; }  
       else if (cc<c2) goto towards_zero;  
       else {  
         cc=0;  
         while (dif>0 && (cc=zp[dif-1])==0) dif--;  
         if (cc) { mpfr_add_one_ulp(f); return cc; }  
         else /* exactly in middle: inexact in both cases */  
           if (*fp & ((mp_limb_t)1<<sh)) { mpfr_add_one_ulp(f); return 1; }  
           else return 1;  
       }  
     }  
     else if ((sign_z>0 && rnd==GMP_RNDU) || (sign_z<0 && rnd==GMP_RNDD)) {  
       /* round towards infinity */  
       /* result is exact iff all remaining bits are zero */  
       if (dif>0 && cc==0) cc=zp[--dif]<<k;  
       while (cc==0 && dif>0) cc=zp[--dif];  
       if (cc) { mpfr_add_one_ulp(f); return 1; }  
       else return 0;  
     }  
     else { /* round towards zero */  
       /* result is exact iff all remaining bits are zero */  
     towards_zero:  
       if (cc==0 && dif>0) cc=zp[--dif]<<k;  
       while (cc==0 && dif>0) cc=zp[--dif];  
       return cc;  
     }  
   }  
   else {  
     if (k) mpn_lshift(fp-dif, zp, zn, k);  
     else MPN_COPY(fp-dif, zp, zn);  
     /* fill with zeroes */  
     MPN_ZERO(fp, -dif);  
     return 0; /* result is exact */  
   }  
 }  
   
     exp = (mp_prec_t) zn * BITS_PER_MP_LIMB - k;
     /* The exponent will be exp or exp + 1 (due to rounding) */
     if (exp > __mpfr_emax)
       return mpfr_set_overflow(f, rnd_mode, sign_z);
     if (exp + 1 < __mpfr_emin)
       return mpfr_set_underflow(f, rnd_mode, sign_z);
   
     if (MPFR_SIGN(f) * sign_z < 0)
       MPFR_CHANGE_SIGN(f);
   
     if (dif >= 0)
       {
         mp_limb_t cc;
         int sh;
   
         /* number has to be truncated */
         if (k != 0)
           {
             mpn_lshift(fp, zp + dif, fn, k);
             if (dif != 0)
               fp[0] += zp[dif - 1] >> (BITS_PER_MP_LIMB - k);
           }
         else
           MPN_COPY(fp, zp + dif, fn);
   
         sh = (mp_prec_t) fn * BITS_PER_MP_LIMB - MPFR_PREC(f);
         cc = fp[0] & ((MP_LIMB_T_ONE << sh) - 1);
         fp[0] &= ~cc;
   
         if ((rnd_mode == GMP_RNDU && sign_z < 0) ||
             (rnd_mode == GMP_RNDD && sign_z > 0))
           rnd_mode = GMP_RNDZ;
   
         /* remaining bits... */
         if (rnd_mode == GMP_RNDN)
           {
             /* 1) If rounding bit is 0, behave like rounding to 0.
                2) Determine the sticky bit (cc != 0). */
             if (sh != 0)
               {
                 mp_limb_t rb;
   
                 rb = MP_LIMB_T_ONE << (sh - 1);
                 if ((cc & rb) == 0)
                   rnd_mode = GMP_RNDZ; /* rounding bit is 0 */
                 else
                   cc &= ~rb;
                 if (cc == 0 && dif > 0)
                   cc = zp[--dif] << k;
               }
             else /* sh == 0 */
               {
                 MPFR_ASSERTN(cc == 0);
                 if (dif > 0)
                   cc = zp[--dif] << k;
                 if ((cc & GMP_LIMB_HIGHBIT) == 0)
                   rnd_mode = GMP_RNDZ; /* rounding bit is 0 */
                 else
                   cc <<= 1;
               }
   
             while (cc == 0 && dif > 0)
               cc = zp[--dif];
   
             if (rnd_mode == GMP_RNDN && cc == 0) /* even rounding */
               {
                 cc = 1;
                 if ((fp[0] & (MP_LIMB_T_ONE << sh)) == 0)
                   rnd_mode = GMP_RNDZ;
               }
           } /* rnd_mode == GMP_RNDN */
         else if (cc == 0 && dif > 0)
           {
             cc = zp[--dif] << k;
             while (cc == 0 && dif > 0)
               cc = zp[--dif];
           }
   
         if (cc == 0)
           inex = 0;
         else if (rnd_mode == GMP_RNDZ)
           inex = -sign_z;
         else
           {
             if (mpn_add_1(fp, fp, fn, MP_LIMB_T_ONE << sh))
               {
                 if (exp == __mpfr_emax)
                   return mpfr_set_overflow(f, rnd_mode, sign_z);
                 else
                   {
                     exp++;
                     fp[fn-1] = GMP_LIMB_HIGHBIT;
                   }
               }
             inex = sign_z;
           }
       } /* dif >= 0 */
     else /* dif < 0 */
       {
         if (k != 0)
           mpn_lshift(fp - dif, zp, zn, k);
         else
           MPN_COPY(fp - dif, zp, zn);
         /* fill with zeroes */
         MPN_ZERO(fp, -dif);
         inex = 0; /* result is exact */
       }
   
     if (exp < __mpfr_emin)
       return mpfr_set_underflow(f, rnd_mode, sign_z);
     MPFR_EXP(f) = exp;
     MPFR_RET(inex);
   }
Legend:
Removed from v.1.1.1.1  
changed lines
  Added in v.1.1.1.2
FreeBSD-CVSweb <freebsd-cvsweb@FreeBSD.org>