gas/bignum-copy.c

   1 /* bignum_copy.c - copy a bignum
   2    Copyright 1987, 1990, 1991, 1992, 1993, 2000
   3    Free Software Foundation, Inc.
   4
   5    This file is part of GAS, the GNU Assembler.
   6
   7    GAS is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 2, or (at your option)
  10    any later version.
  11
  12    GAS is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with GAS; see the file COPYING.  If not, write to
  19    the Free Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  20
  21 #include "as.h"
  22
  23 /*
  24  *                      bignum_copy ()
  25  *
  26  * Copy a bignum from in to out.
  27  * If the output is shorter than the input, copy lower-order littlenums.
  28  * Return 0 or the number of significant littlenums dropped.
  29  * Assumes littlenum arrays are densely packed: no unused chars between
  30  * the littlenums. Uses memcpy() to move littlenums, and wants to
  31  * know length (in chars) of the input bignum.
  32  */
  33
  34 /* void */
  35 int
  36 bignum_copy (register LITTLENUM_TYPE *in,
  37              register int in_length,    /* in sizeof(littlenum)s */
  38              register LITTLENUM_TYPE *out,
  39              register int out_length    /* in sizeof(littlenum)s */)
  40 {
  41   int significant_littlenums_dropped;
  42
  43   if (out_length < in_length)
  44     {
  45       LITTLENUM_TYPE *p;        /* -> most significant (non-zero) input
  46                                       littlenum.  */
  47
  48       memcpy ((void *) out, (void *) in,
  49               (unsigned int) out_length << LITTLENUM_SHIFT);
  50       for (p = in + in_length - 1; p >= in; --p)
  51         {
  52           if (*p)
  53             break;
  54         }
  55       significant_littlenums_dropped = p - in - in_length + 1;
  56
  57       if (significant_littlenums_dropped < 0)
  58         {
  59           significant_littlenums_dropped = 0;
  60         }
  61     }
  62   else
  63     {
  64       memcpy ((char *) out, (char *) in,
  65               (unsigned int) in_length << LITTLENUM_SHIFT);
  66
  67       if (out_length > in_length)
  68         {
  69           memset ((char *) (out + in_length),
  70                   '\0',
  71                   (unsigned int) (out_length - in_length) << LITTLENUM_SHIFT);
  72         }
  73
  74       significant_littlenums_dropped = 0;
  75     }
  76
  77   return (significant_littlenums_dropped);
  78 }                               /* bignum_copy() */
  79
  80 /* end of bignum-copy.c */