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, 675 Mass Ave, Cambridge, MA 02139, 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                 LITTLENUM_TYPE *p; /* -> most significant (non-zero) input
  45                                       littlenum. */
  46
  47                 memcpy((void *) out, (void *) in,
  48                       out_length << LITTLENUM_SHIFT);
  49                 for (p = in + in_length - 1; p >= in; --p) {
  50                         if (* p) break;
  51                 }
  52                 significant_littlenums_dropped = p - in - in_length + 1;
  53
  54                 if (significant_littlenums_dropped < 0) {
  55                         significant_littlenums_dropped = 0;
  56                 }
  57         } else {
  58                 memcpy((char *) out, (char *) in,
  59                       in_length << LITTLENUM_SHIFT);
  60
  61                 if (out_length > in_length) {
  62                         memset((char *) (out + out_length),
  63                               '\0', (out_length - in_length) << LITTLENUM_SHIFT);
  64                 }
  65
  66                 significant_littlenums_dropped = 0;
  67         }
  68
  69         return(significant_littlenums_dropped);
  70 } /* bignum_copy() */
  71
  72 /* end of bignum-copy.c */