sysdeps/i386/selectbits.h

   1 /* Copyright (C) 1997 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 Library General Public License as
   6    published by the Free Software Foundation; either version 2 of the
   7    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    Library General Public License for more details.
  13
  14    You should have received a copy of the GNU Library General Public
  15    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  16    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17    Boston, MA 02111-1307, USA.  */
  18
  19 #ifndef _SELECTBITS_H
  20 #define _SELECTBITS_H   1
  21
  22 #if defined __GNUC__ && __GNUC__ >= 2
  23
  24 #define __FD_ZERO(fdsetp) \
  25   __asm__ __volatile__ ("cld ; rep ; stosl"                                   \
  26                         : "=m" (*(__fd_set *) (fdsetp))                       \
  27                         : "a" (0), "c" (sizeof (__fd_set)                     \
  28                                         / sizeof (__fd_mask)),                \
  29                           "D" ((__fd_set *) (fdsetp))                         \
  30                         :"cx","di")
  31 #define __FD_SET(fd, fdsetp) \
  32   __asm__ __volatile__ ("btsl %1,%0"                                          \
  33                         : "=m" (*(__fd_set *) (fdsetp))                       \
  34                         : "r" ((int) (fd)))
  35 #define __FD_CLR(fd, fdsetp) \
  36   __asm__ __volatile__ ("btrl %1,%0"                                          \
  37                         : "=m" (*(__fd_set *) (fdsetp))                       \
  38                         : "r" ((int) (fd)))
  39 #define __FD_ISSET(fd, fdsetp) \
  40   (__extension__                                                              \
  41    ({unsigned char __result;                                                  \
  42      __asm__ __volatile__ ("btl %1,%2 ; setb %0"                              \
  43                            : "=q" (__result)                                  \
  44                            : "r" ((int) (fd)), "m" (*(__fd_set *) (fdsetp))); \
  45      __result; }))
  46
  47 #else   /* ! GNU CC */
  48
  49 #define __FD_ZERO(set)  \
  50   ((void) memset ((__ptr_t) (set), 0, sizeof (fd_set)))
  51 #define __FD_SET(d, set)        ((set)->fds_bits[__FDELT(d)] |= __FDMASK(d))
  52 #define __FD_CLR(d, set)        ((set)->fds_bits[__FDELT(d)] &= ~__FDMASK(d))
  53 #define __FD_ISSET(d, set)      ((set)->fds_bits[__FDELT(d)] & __FDMASK(d))
  54
  55 #endif  /* GNU CC */
  56
  57 #endif /* selectbits.h */