Constify string parameters
[glibc.git] / sysdeps / s390 / ffs.c
blob7debcc502c18a309a23465e9df425df6a4a82618
1 /* ffs -- find first set bit in a word, counted from least significant end.
2 S/390 version.
3 Copyright (C) 2000-2014 Free Software Foundation, Inc.
4 Contributed by Martin Schwidefsky (schwidefsky@de.ibm.com).
5 This file is part of the GNU C Library.
7 The GNU C Library is free software; you can redistribute it and/or
8 modify it under the terms of the GNU Lesser General Public
9 License as published by the Free Software Foundation; either
10 version 2.1 of the License, or (at your option) any later version.
12 The GNU C Library is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 Lesser General Public License for more details.
17 You should have received a copy of the GNU Lesser General Public
18 License along with the GNU C Library; if not, see
19 <http://www.gnu.org/licenses/>. */
21 #include <limits.h>
22 #define ffsl __something_else
23 #include <string.h>
25 #undef ffs
27 /* ffs: find first bit set. This is defined the same way as
28 the libc and compiler builtin ffs routines, therefore
29 differs in spirit from the above ffz (man ffs). */
31 int
32 __ffs (x)
33 int x;
35 int r;
37 if (x == 0)
38 return 0;
39 __asm__(" lr %%r1,%1\n"
40 " sr %0,%0\n"
41 " tml %%r1,0xFFFF\n"
42 " jnz 0f\n"
43 " ahi %0,16\n"
44 " srl %%r1,16\n"
45 "0: tml %%r1,0x00FF\n"
46 " jnz 1f\n"
47 " ahi %0,8\n"
48 " srl %%r1,8\n"
49 "1: tml %%r1,0x000F\n"
50 " jnz 2f\n"
51 " ahi %0,4\n"
52 " srl %%r1,4\n"
53 "2: tml %%r1,0x0003\n"
54 " jnz 3f\n"
55 " ahi %0,2\n"
56 " srl %%r1,2\n"
57 "3: tml %%r1,0x0001\n"
58 " jnz 4f\n"
59 " ahi %0,1\n"
60 "4:"
61 : "=&d" (r) : "d" (x) : "cc", "1" );
62 return r+1;
65 weak_alias (__ffs, ffs)
66 libc_hidden_def (__ffs)
67 libc_hidden_builtin_def (ffs)
68 #if ULONG_MAX == UINT_MAX
69 #undef ffsl
70 weak_alias (__ffs, ffsl)
71 #endif