yap-6.3/OPTYap/mips_locks_funcs.h

/**********************************************************************
                                                               
                       The OPTYap Prolog system                
  OPTYap extends the Yap Prolog system to support or-parallel tabling
                                                               
  Copyright:   R. Rocha and NCC - University of Porto, Portugal
  File:        mips_locks_funcs.h  
  version:     $Id: mips_locks_funcs.h,v 1.2 2005-05-31 08:24:24 ricroc Exp $   
                                                                     
**********************************************************************/

/* ------------------------------- **
**      Atomic locking for MIPS    **
** ------------------------------- */

static __inline__ int test_and_set_bit(int nr, volatile void *addr)
{
	int	mask, retval, mw;

	mask = 1;
	do {
		mw = load_linked(addr);
		retval = (mask & mw) != 0;
	} while (!store_conditional(addr, mw|mask));

	return retval;
}

static inline void _spin_lock(__dummy_lock_t *lock)
{
	unsigned int tmp;

	__asm__ __volatile__(
	".set\tnoreorder\t\t\t# spin_lock\n"
	"1:\tll\t%1, %2\n\t"
	"bnez\t%1, 1b\n\t"
	" li\t%1, 1\n\t"
	"sc\t%1, %0\n\t"
	"beqz\t%1, 1b\n\t"
	" sync\n\t"
	".set\treorder"
	: "=o" (__dummy_lock(lock)), "=&r" (tmp)
	: "o" (__dummy_lock(lock))
	: "memory");
}

static inline void spin_unlock(__dummy_lock_t *lock)
{
	__asm__ __volatile__(
	".set\tnoreorder\t\t\t# spin_unlock\n\t"
	"sync\n\t"
	"sw\t$0, %0\n\t"
	".set\treorder"	
	: "=o" (__dummy_lock(lock))
	: "o" (__dummy_lock(lock))
	: "memory");
}

static inline void _read_lock(rwlock_t *rw)
{
	unsigned int tmp;

	__asm__ __volatile__(
	".set\tnoreorder\t\t\t# read_lock\n"
	"1:\tll\t%1, %2\n\t"
	"bltz\t%1, 1b\n\t"
	" addu\t%1, 1\n\t"
	"sc\t%1, %0\n\t"
	"beqz\t%1, 1b\n\t"
	" sync\n\t"
	".set\treorder"	
	: "=o" (__dummy_lock(rw)), "=&r" (tmp)
	: "o" (__dummy_lock(rw))
	: "memory");
}

/* Note the use of sub, not subu which will make the kernel die with an
   overflow exception if we ever try to unlock an rwlock that is already
   unlocked or is being held by a writer.  */
static inline void _read_unlock(rwlock_t *rw)
{
	unsigned int tmp;

	__asm__ __volatile__(
	".set\tnoreorder\t\t\t# read_unlock\n"
	"1:\tll\t%1, %2\n\t"
	"sub\t%1, 1\n\t"
	"sc\t%1, %0\n\t"
	"beqz\t%1, 1b\n\t"
	".set\treorder"	
	: "=o" (__dummy_lock(rw)), "=&r" (tmp)
	: "o" (__dummy_lock(rw))
	: "memory");
}

static inline void _write_lock(rwlock_t *rw)
{
	unsigned int tmp;

	__asm__ __volatile__(
	".set\tnoreorder\t\t\t# write_lock\n"
	"1:\tll\t%1, %2\n\t"
	"bnez\t%1, 1b\n\t"
	" lui\t%1, 0x8000\n\t"
	"sc\t%1, %0\n\t"
	"beqz\t%1, 1b\n\t"
	" sync\n\t"
	".set\treorder"	
	: "=o" (__dummy_lock(rw)), "=&r" (tmp)
	: "o" (__dummy_lock(rw))
	: "memory");
}

static inline void _write_unlock(rwlock_t *rw)
{
	__asm__ __volatile__(
	".set\tnoreorder\t\t\t# write_unlock\n\t"
	"sync\n\t"
	"sw\t$0, %0\n\t"
	".set\treorder"	
	: "=o" (__dummy_lock(rw))
	: "o" (__dummy_lock(rw))
	: "memory");
}