1 /* Machine-dependent pthreads configuration and inline functions.
2 ARM version.
3 Copyright (C) 1997, 1998, 2000, 2002, 2003 Free Software Foundation, Inc.
4 This file is part of the GNU C Library.
5 Contributed by Philip Blundell <philb@gnu.org>.
6
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 License as
9 published by the Free Software Foundation; either version 2.1 of the
10 License, or (at your option) any later version.
11
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.
16
17 You should have received a copy of the GNU Lesser General Public
18 License along with the GNU C Library; see the file COPYING.LIB. If not,
19 write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
20 Boston, MA 02111-1307, USA. */
21
22 #ifndef _PT_MACHINE_H
23 #define _PT_MACHINE_H 1
24
25 #include <features.h>
26
27 /* This will not work on ARM1 or ARM2 because SWP is lacking on those
28 machines. Unfortunately we have no way to detect this at compile
29 time; let's hope nobody tries to use one. */
30
31 /* Spinlock implementation; required. */
32 L4_INLINE long int
testandset(int * spinlock)33 testandset (int *spinlock)
34 {
35 return __atomic_exchange_n(spinlock, 1, __ATOMIC_ACQUIRE);
36 }
37
38
39 /* Get some notion of the current stack. Need not be exactly the top
40 of the stack, just something somewhere in the current frame. */
41 #define CURRENT_STACK_FRAME stack_pointer
42 register char * stack_pointer __asm__ ("sp");
43
44 /* Compare-and-swap for semaphores. It's always available on i686. */
45 #define HAS_COMPARE_AND_SWAP
46
47 L4_INLINE int
__compare_and_swap(long int * p,long int oldval,long int newval)48 __compare_and_swap (long int *p, long int oldval, long int newval)
49 {
50 return __atomic_compare_exchange_n(p, &oldval, newval, 0,
51 __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST);
52 }
53
54 #endif /* pt-machine.h */
55