gas/bignum-copy.c

   1 /* bignum_copy.c - copy a bignum
   2    Copyright (C) 1987, 1990, 1991, 1992 Free Software Foundation, Inc.
   3
   4    This file is part of GAS, the GNU Assembler.
   5
   6    GAS is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 2, or (at your option)
   9    any later version.
  10
  11    GAS is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with GAS; see the file COPYING.  If not, write to
  18    the Free Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
  19
  20 #include "as.h"
  21
  22 /*
  23  *                      bignum_copy ()
  24  *
  25  * Copy a bignum from in to out.
  26  * If the output is shorter than the input, copy lower-order littlenums.
  27  * Return 0 or the number of significant littlenums dropped.
  28  * Assumes littlenum arrays are densely packed: no unused chars between
  29  * the littlenums. Uses memcpy() to move littlenums, and wants to
  30  * know length (in chars) of the input bignum.
  31  */
  32
  33 /* void */
  34 int
  35 bignum_copy (in, in_length, out, out_length)
  36      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 */