1 /* Copyright (C) 1997-1999,2001,2008,2009,2011 Free Software Foundation, Inc.
2    This file is part of the GNU C Library.
3 
4    The GNU C Library is free software; you can redistribute it and/or
5    modify it under the terms of the GNU Lesser General Public
6    License as published by the Free Software Foundation; either
7    version 2.1 of the License, or (at your option) any later version.
8 
9    The GNU C Library is distributed in the hope that it will be useful,
10    but WITHOUT ANY WARRANTY; without even the implied warranty of
11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
12    Lesser General Public License for more details.
13 
14    You should have received a copy of the GNU Lesser General Public
15    License along with the GNU C Library; if not, see
16    <http://www.gnu.org/licenses/>.  */
17 
18 #ifndef _SYS_SELECT_H
19 # error "Never use <bits/select.h> directly; include <sys/select.h> instead."
20 #endif
21 
22 #include <bits/wordsize.h>
23 
24 
25 #if defined __GNUC__ && __GNUC__ >= 2
26 
27 # if __WORDSIZE == 64
28 #  define __FD_ZERO_STOS "stosq"
29 # else
30 #  define __FD_ZERO_STOS "stosl"
31 # endif
32 
33 # define __FD_ZERO(fdsp) \
34   do {									      \
35     int __d0, __d1;							      \
36     __asm__ __volatile__ ("cld; rep; " __FD_ZERO_STOS			      \
37 			  : "=c" (__d0), "=D" (__d1)			      \
38 			  : "a" (0), "0" (sizeof (fd_set)		      \
39 					  / sizeof (__fd_mask)),	      \
40 			    "1" (&__FDS_BITS (fdsp)[0])			      \
41 			  : "memory");					      \
42   } while (0)
43 
44 #else	/* ! GNU CC */
45 
46 /* We don't use `memset' because this would require a prototype and
47    the array isn't too big.  */
48 # define __FD_ZERO(set)  \
49   do {									      \
50     unsigned int __i;							      \
51     fd_set *__arr = (set);						      \
52     for (__i = 0; __i < sizeof (fd_set) / sizeof (__fd_mask); ++__i)	      \
53       __FDS_BITS (__arr)[__i] = 0;					      \
54   } while (0)
55 
56 #endif	/* GNU CC */
57 
58 #define __FD_SET(d, set) \
59   ((void) (__FDS_BITS (set)[__FD_ELT (d)] |= __FD_MASK (d)))
60 #define __FD_CLR(d, set) \
61   ((void) (__FDS_BITS (set)[__FD_ELT (d)] &= ~__FD_MASK (d)))
62 #define __FD_ISSET(d, set) \
63   ((__FDS_BITS (set)[__FD_ELT (d)] & __FD_MASK (d)) != 0)
64