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Annotation of OpenXM_contrib/gmp/mpf/add_ui.c, Revision 1.1.1.2

1.1       maekawa     1: /* mpf_add_ui -- Add a float and an unsigned integer.
                      2:
                      3: Copyright (C) 1993, 1994, 1996 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
1.1.1.2 ! maekawa     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
1.1       maekawa    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
1.1.1.2 ! maekawa    14: or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
1.1       maekawa    15: License for more details.
                     16:
1.1.1.2 ! maekawa    17: You should have received a copy of the GNU Lesser General Public License
1.1       maekawa    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: #include "gmp.h"
                     23: #include "gmp-impl.h"
                     24:
                     25: void
                     26: #if __STDC__
                     27: mpf_add_ui (mpf_ptr sum, mpf_srcptr u, unsigned long int v)
                     28: #else
                     29: mpf_add_ui (sum, u, v)
                     30:      mpf_ptr sum;
                     31:      mpf_srcptr u;
                     32:      unsigned long int v;
                     33: #endif
                     34: {
                     35:   mp_srcptr up = u->_mp_d;
                     36:   mp_ptr sump = sum->_mp_d;
                     37:   mp_size_t usize, sumsize;
                     38:   mp_size_t prec = sum->_mp_prec;
                     39:   mp_exp_t uexp = u->_mp_exp;
                     40:
                     41:   usize = u->_mp_size;
                     42:   if (usize <= 0)
                     43:     {
                     44:       if (usize == 0)
                     45:        {
                     46:          mpf_set_ui (sum, v);
                     47:          return;
                     48:        }
                     49:       else
                     50:        {
                     51:          __mpf_struct u_negated;
                     52:          u_negated._mp_size = -usize;
                     53:          u_negated._mp_exp = u->_mp_exp;
                     54:          u_negated._mp_d = u->_mp_d;
                     55:          mpf_sub_ui (sum, &u_negated, v);
                     56:          sum->_mp_size = -(sum->_mp_size);
                     57:          return;
                     58:        }
                     59:     }
                     60:
                     61:   if (v == 0)
                     62:     {
                     63:     sum_is_u:
                     64:       if (u != sum)
                     65:        {
                     66:          sumsize = MIN (usize, prec + 1);
                     67:          MPN_COPY (sum->_mp_d, up + usize - sumsize, sumsize);
                     68:          sum->_mp_size = sumsize;
                     69:          sum->_mp_exp = u->_mp_exp;
                     70:        }
                     71:       return;
                     72:     }
                     73:
                     74:   if (uexp > 0)
                     75:     {
                     76:       /* U >= 1.  */
                     77:       if (uexp > prec)
                     78:        {
                     79:          /* U >> V, V is not part of final result.  */
                     80:          goto sum_is_u;
                     81:        }
                     82:       else
                     83:        {
                     84:          /* U's "limb point" is somewhere between the first limb
                     85:             and the PREC:th limb.
                     86:             Both U and V are part of the final result.  */
                     87:          if (uexp > usize)
                     88:            {
                     89:              /*   uuuuuu0000. */
                     90:              /* +          v. */
                     91:              /* We begin with moving U to the top of SUM, to handle
                     92:                 samevar(U,SUM).  */
                     93:              MPN_COPY_DECR (sump + uexp - usize, up, usize);
                     94:              sump[0] = v;
                     95:              MPN_ZERO (sump + 1, uexp - usize - 1);
                     96: #if 0 /* What is this??? */
                     97:              if (sum == u)
                     98:                MPN_COPY (sum->_mp_d, sump, uexp);
                     99: #endif
                    100:              sum->_mp_size = uexp;
                    101:              sum->_mp_exp = uexp;
                    102:            }
                    103:          else
                    104:            {
                    105:              /*   uuuuuu.uuuu */
                    106:              /* +      v.     */
                    107:              mp_limb_t cy_limb;
                    108:              if (usize > prec)
                    109:                {
                    110:                  /* Ignore excess limbs in U.  */
                    111:                  up += usize - prec;
                    112:                  usize -= usize - prec; /* Eq. usize = prec */
                    113:                }
                    114:              if (sump != up)
                    115:                MPN_COPY (sump, up, usize - uexp);
                    116:              cy_limb = mpn_add_1 (sump + usize - uexp, up + usize - uexp,
                    117:                                   uexp, (mp_limb_t) v);
                    118:              sump[usize] = cy_limb;
                    119:              sum->_mp_size = usize + cy_limb;
                    120:              sum->_mp_exp = uexp + cy_limb;
                    121:            }
                    122:        }
                    123:     }
                    124:   else
                    125:     {
                    126:       /* U < 1, so V > U for sure.  */
                    127:       /* v.         */
                    128:       /*  .0000uuuu */
                    129:       if ((-uexp) >= prec)
                    130:        {
                    131:          sump[0] = v;
                    132:          sum->_mp_size = 1;
                    133:          sum->_mp_exp = 1;
                    134:        }
                    135:       else
                    136:        {
                    137:          if (usize + (-uexp) + 1 > prec)
                    138:            {
                    139:              /* Ignore excess limbs in U.  */
                    140:              up += usize + (-uexp) + 1 - prec;
                    141:              usize -= usize + (-uexp) + 1 - prec;
                    142:            }
                    143:          if (sump != up)
                    144:            MPN_COPY (sump, up, usize);
                    145:          MPN_ZERO (sump + usize, -uexp);
                    146:          sump[usize + (-uexp)] = v;
                    147:          sum->_mp_size = usize + (-uexp) + 1;
                    148:          sum->_mp_exp = 1;
                    149:        }
                    150:     }
                    151: }