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Annotation of OpenXM_contrib/gmp/mpf/add_ui.c, Revision 1.1

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
        !             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 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 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 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: }