libitm/config/linux/x86/futex_bits.h

/* Copyright (C) 2008-2014 Free Software Foundation, Inc.
   Contributed by Richard Henderson <rth@redhat.com>.

   This file is part of the GNU Transactional Memory Library (libitm).

   Libitm is free software; you can redistribute it and/or modify it
   under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   Libitm is distributed in the hope that it will be useful, but WITHOUT ANY
   WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
   FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
   more details.

   Under Section 7 of GPL version 3, you are granted additional
   permissions described in the GCC Runtime Library Exception, version
   3.1, as published by the Free Software Foundation.

   You should have received a copy of the GNU General Public License and
   a copy of the GCC Runtime Library Exception along with this program;
   see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
   <http://www.gnu.org/licenses/>.  */

#ifdef __x86_64__
# ifndef SYS_futex
#  define SYS_futex	202
# endif

static inline long
sys_futex0 (std::atomic<int> *addr, long op, long val)
{
  register long r10 __asm__("%r10") = 0;
  long res;

  __asm volatile ("syscall"
		  : "=a" (res)
		  : "0" (SYS_futex), "D" (addr), "S" (op), "d" (val), "r" (r10)
		  : "r11", "rcx", "memory");

  return res;
}

#else
# ifndef SYS_futex
#  define SYS_futex	240
# endif

# ifdef __PIC__

static inline long
sys_futex0 (std::atomic<int> *addr, int op, int val)
{
  long res;

  __asm volatile ("xchgl\t%%ebx, %2\n\t"
		  "int\t$0x80\n\t"
		  "xchgl\t%%ebx, %2"
		  : "=a" (res)
		  : "0"(SYS_futex), "r" (addr), "c"(op),
		    "d"(val), "S"(0)
		  : "memory");
  return res;
}

# else

static inline long
sys_futex0 (std::atomic<int> *addr, int op, int val)
{
  long res;

  __asm volatile ("int $0x80"
		  : "=a" (res)
		  : "0"(SYS_futex), "b" (addr), "c"(op),
		    "d"(val), "S"(0)
		  : "memory");
  return res;
}

# endif /* __PIC__ */
#endif /* __x86_64__ */