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movebytes.c
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C/C++ Source or Header
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2000-05-07
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3KB
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125 lines
/* @(#)movebytes.c 1.12 00/05/07 Copyright 1985 J. Schilling */
/*
* move data
*
* Copyright (c) 1985 J. Schilling
*/
/*
* This program 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 2, or (at your option)
* any later version.
*
* This program 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 this program; see the file COPYING. If not, write to
* the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <standard.h>
#include <align.h>
#include <schily.h>
#define DO8(a) a;a;a;a;a;a;a;a;
char *movebytes(fromv, tov, cnt)
const void *fromv;
void *tov;
int cnt;
{
register const char *from = fromv;
register char *to = tov;
register int n;
/*
* If we change cnt to be unsigned, check for == instead of <=
*/
if ((n = cnt) <= 0)
return (to);
if (from >= to) {
/*
* source is on higher adresses than destination:
* move bytes forwards
*/
if (n >= (int)(8 * sizeof(long))) {
if (l2aligned(from, to)) {
register const long *froml = (const long *)from;
register long *tol = (long *)to;
register int rem = n % (8 * sizeof (long));
n /= (8 * sizeof (long));
do {
DO8 (*tol++ = *froml++);
} while (--n > 0);
from = (const char *)froml;
to = (char *)tol;
n = rem;
}
if (n >= 8) {
n -= 8;
do {
DO8 (*to++ = *from++);
} while ((n -= 8) >= 0);
n += 8;
}
if (n > 0) do {
*to++ = *from++;
} while (--n > 0);
return (to);
}
if (n > 0) do {
*to++ = *from++;
} while (--n > 0);
return (to);
} else {
char *ep;
/*
* source is on lower adresses than destination:
* move bytes backwards
*/
to += n;
from += n;
ep = to;
if (n >= (int)(8 * sizeof(long))) {
if (l2aligned(from, to)) {
register const long *froml = (const long *)from;
register long *tol = (long *)to;
register int rem = n % (8 * sizeof (long));
n /= (8 * sizeof (long));
do {
DO8 (*--tol = *--froml);
} while (--n > 0);
from = (const char *)froml;
to = (char *)tol;
n = rem;
}
if (n >= 8) {
n -= 8;
do {
DO8 (*--to = *--from);
} while ((n -= 8) >= 0);
n += 8;
}
if (n > 0) do {
*--to = *--from;
} while (--n > 0);
return (ep);
}
if (n > 0) do {
*--to = *--from;
} while (--n > 0);
return (ep);
}
}