1 /* Set a block of memory to some byte value.
3 Copyright (C) 1991, 1992, 1993, 1997, 1998 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 not,
18 write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
19 Boston, MA 02111-1307, USA. */
29 memset (void *dstpp, int c, size_t len)
32 unsigned long int dstp = (unsigned long int) dstpp;
34 /* This explicit register allocation
35 improves code very much indeed. */
36 register op_t x asm("ax");
38 x = (unsigned char) c;
40 /* Clear the direction flag, so filling will move forward. */
43 /* This threshold value is optimal. */
46 /* Fill X with four copies of the char we want to fill with. */
50 /* Adjust LEN for the bytes handled in the first loop. */
51 len -= (-dstp) % OPSIZ;
53 /* There are at least some bytes to set.
54 No need to test for LEN == 0 in this alignment loop. */
56 /* Fill bytes until DSTP is aligned on a longword boundary. */
58 "stosb" /* %0, %2, %3 */ :
59 "=D" (dstp), "=c" (d0) :
60 "0" (dstp), "1" ((-dstp) % OPSIZ), "a" (x) :
65 "stosl" /* %0, %2, %3 */ :
66 "=D" (dstp), "=c" (d0) :
67 "0" (dstp), "1" (len / OPSIZ), "a" (x) :
72 /* Write the last few bytes. */
74 "stosb" /* %0, %2, %3 */ :
75 "=D" (dstp), "=c" (d0) :
76 "0" (dstp), "1" (len), "a" (x) :
83 #include <sysdeps/generic/memset.c>