NetBSD/gnu/usr.bin/gas/bignum-copy.c

80 lines
2.4 KiB
C

/* bignum_copy.c - copy a bignum
Copyright (C) 1987 Free Software Foundation, Inc.
This file is part of GAS, the GNU Assembler.
GAS is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 1, or (at your option)
any later version.
GAS is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with GAS; see the file COPYING. If not, write to
the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
#ifndef lint
static char rcsid[] = "$Id: bignum-copy.c,v 1.2 1993/08/02 17:28:07 mycroft Exp $";
#endif /* not lint */
#include "bignum.h"
#ifdef USG
#define bzero(s,n) memset(s,0,n)
#define bcopy(from,to,n) memcpy(to,from,n)
#endif
/*
* bignum_copy ()
*
* Copy a bignum from in to out.
* If the output is shorter than the input, copy lower-order littlenums.
* Return 0 or the number of significant littlenums dropped.
* Assumes littlenum arrays are densely packed: no unused chars between
* the littlenums. Uses bcopy() to move littlenums, and wants to
* know length (in chars) of the input bignum.
*/
/* void */
int
bignum_copy (in, in_length, out, out_length)
register LITTLENUM_TYPE * in;
register int in_length; /* in sizeof(littlenum)s */
register LITTLENUM_TYPE * out;
register int out_length; /* in sizeof(littlenum)s */
{
register int significant_littlenums_dropped;
if (out_length < in_length)
{
register LITTLENUM_TYPE * p; /* -> most significant (non-zero) input littlenum. */
bcopy ((char *)in, (char *)out, out_length << LITTLENUM_SHIFT);
for (p = in + in_length - 1; p >= in; -- p)
{
if (* p) break;
}
significant_littlenums_dropped = p - in - in_length + 1;
if (significant_littlenums_dropped < 0)
{
significant_littlenums_dropped = 0;
}
}
else
{
bcopy ((char *)in, (char *)out, in_length << LITTLENUM_SHIFT);
if (out_length > in_length)
{
bzero ((char *)(out + out_length), (out_length - in_length) << LITTLENUM_SHIFT);
}
significant_littlenums_dropped = 0;
}
return (significant_littlenums_dropped);
}
/* end: bignum_copy.c */