uclibc-ng/libpthread/linuxthreads/sysdeps/avr32/pt-machine.h

/* Machine-dependent pthreads configuration and inline functions.
 *
 * Copyright (C) 2005-2007 Atmel Corporation
 *
 * This file is subject to the terms and conditions of the GNU Lesser General
 * Public License.  See the file "COPYING.LIB" in the main directory of this
 * archive for more details.
 */
#ifndef _PT_MACHINE_H
#define _PT_MACHINE_H   1

#include <features.h>

static inline int
_test_and_set (int *p, int v) __THROW
{
       int result;

       __asm__ __volatile__(
               "/* Inline test and set */\n"
               "       xchg    %[old], %[mem], %[new]"
               : [old] "=&r"(result)
               : [mem] "r"(p), [new] "r"(v)
               : "memory");

       return result;
}

#ifndef PT_EI
# define PT_EI extern inline
#endif

extern long int testandset (int *spinlock);
extern int __compare_and_swap (long int *p, long int oldval, long int newval);

/* Spinlock implementation; required.  */
PT_EI long int
testandset (int *spinlock)
{
       return _test_and_set(spinlock, 1);
}


/* Get some notion of the current stack.  Need not be exactly the top
   of the stack, just something somewhere in the current frame.  */
#define CURRENT_STACK_FRAME  stack_pointer
register char * stack_pointer __asm__ ("sp");

/* Compare-and-swap for semaphores. */

#define HAS_COMPARE_AND_SWAP
PT_EI int
__compare_and_swap(long int *p, long int oldval, long int newval)
{
       int result;

       __asm__ __volatile__(
               "/* Inline compare and swap */\n"
               "1:     ssrf    5\n"
               "       ld.w    %[result], %[mem]\n"
               "       eor     %[result], %[old]\n"
               "       brne    2f\n"
               "       stcond  %[mem], %[new]\n"
               "       brne    1b\n"
               "2:"
               : [result] "=&r"(result), [mem] "=m"(*p)
               : "m"(*p), [new] "r"(newval), [old] "r"(oldval)
               : "cc", "memory");

       return result == 0;
}

#endif /* pt-machine.h */