1 /* memset -- set a block of memory to some byte value.
3 Copyright (C) 1991, 1992, 1993 Free Software Foundation, Inc.
4 Contributed by Torbjorn Granlund (tege@sics.se).
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Library General Public License as
8 published by the Free Software Foundation; either version 2 of the
9 License, or (at your option) any later version.
11 The GNU C Library 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 GNU
14 Library General Public License for more details.
16 You should have received a copy of the GNU Library General Public
17 License along with the GNU C Library; see the file COPYING.LIB. If
18 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
19 Cambridge, MA 02139, USA. */
28 DEFUN(memset
, (dstpp
, c
, len
),
29 PTR dstpp AND
int c AND
size_t len
)
31 unsigned long int dstp
= (unsigned long int) dstpp
;
33 /* This explicit register allocation
34 improves code very much indeed. */
35 register op_t x
asm("ax");
37 x
= (unsigned char) c
;
39 /* Clear the direction flag, so filling will move forward. */
42 /* This threshold value is optimal. */
45 /* Fill X with four copies of the char we want to fill with. */
49 /* Adjust LEN for the bytes handled in the first loop. */
50 len
-= (-dstp
) % OPSIZ
;
52 /* There are at least some bytes to set.
53 No need to test for LEN == 0 in this alignment loop. */
55 /* Fill bytes until DSTP is aligned on a longword boundary. */
57 "stosb" /* %0, %2, %3 */ :
59 "0" (dstp
), "c" ((-dstp
) % OPSIZ
), "a" (x
) :
64 "stosl" /* %0, %2, %3 */ :
66 "0" (dstp
), "c" (len
/ OPSIZ
), "a" (x
) :
71 /* Write the last few bytes. */
73 "stosb" /* %0, %2, %3 */ :
75 "0" (dstp
), "c" (len
), "a" (x
) :
82 #include <sysdeps/generic/memset.c>