glibc/sysdeps/generic/bzero.c

82 lines
2.1 KiB
C

/* Copyright (C) 1991 Free Software Foundation, Inc.
Contributed by Torbjorn Granlund (tege@sics.se).
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
The GNU C Library 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If
not, write to the Free Software Foundation, Inc., 675 Mass Ave,
Cambridge, MA 02139, USA. */
#include <ansidecl.h>
#include <string.h>
#include <memcopy.h>
/* Set N bytes of S to 0. */
void
DEFUN(bzero, (s, n), PTR s AND size_t len)
{
long int dstp = (long int) s;
CONST op_t zero = 0;
if (len >= 8)
{
size_t xlen;
/* There are at least some bytes to zero. No need to test
for LEN == 0 in this alignment loop. */
while (dstp % OPSIZ != 0)
{
((byte *) dstp)[0] = 0;
dstp += 1;
len -= 1;
}
/* Write 8 op_t per iteration until less than 8 op_t remain. */
xlen = len / (OPSIZ * 8);
while (xlen != 0)
{
((op_t *) dstp)[0] = zero;
((op_t *) dstp)[1] = zero;
((op_t *) dstp)[2] = zero;
((op_t *) dstp)[3] = zero;
((op_t *) dstp)[4] = zero;
((op_t *) dstp)[5] = zero;
((op_t *) dstp)[6] = zero;
((op_t *) dstp)[7] = zero;
dstp += 8 * OPSIZ;
xlen -= 1;
}
len %= OPSIZ * 8;
/* Write 1 op_t per iteration until less than op_t remain. */
xlen = len / OPSIZ;
while (xlen != 0)
{
((op_t *) dstp)[0] = zero;
dstp += OPSIZ;
xlen -= 1;
}
len %= OPSIZ;
}
/* Write the last few bytes. */
while (len != 0)
{
((byte *) dstp)[0] = 0;
dstp += 1;
len -= 1;
}
}