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
bignum_copy(register LITTLENUM_TYPE * in,register int in_length,register LITTLENUM_TYPE * out,register int out_length)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 */
81