text: /* $OpenBSD: atomic.h,v 1.2 2000/11/08 21:27:16 ericj Exp $ */
  /* $NetBSD: atomic.h,v 1.5 2000/06/08 02:54:55 thorpej Exp $ */
  
  /*-
   * Copyright (c) 1998, 1999 The NetBSD Foundation, Inc.
   * All rights reserved.
   *
   * This code is derived from software contributed to The NetBSD Foundation
   * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
   * NASA Ames Research Center.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   * 3. All advertising materials mentioning features or use of this software
   *    must display the following acknowledgement:
   *	This product includes software developed by the NetBSD
   *	Foundation, Inc. and its contributors.
   * 4. Neither the name of The NetBSD Foundation nor the names of its
   *    contributors may be used to endorse or promote products derived
   *    from this software without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
   * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
   * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
   * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
   * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
   * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
   * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
   * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
   * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   * POSSIBILITY OF SUCH DAMAGE.
   */
  
  /*
   * Misc. `atomic' operations.
   */
  
  #ifndef _ALPHA_ATOMIC_H_
  #define	_ALPHA_ATOMIC_H_
  
  /*
   * atomic_setbits_ulong:
   *
   *	Atomically set bits in a `unsigned long'.
   */
  static __inline void
  atomic_setbits_ulong(__volatile unsigned long *ulp, unsigned long v)
  {
  #if 1
  	*ulp |= v;
  #else
  	unsigned long t0;
  
  	__asm __volatile(
  		"# BEGIN atomic_setbits_ulong\n"
  		"1:	ldq_l	%0, %3		\n"
  		"	or	%0, %2, %0	\n"
  		"	stq_c	%0, %1		\n"
  		"	beq	%0, 2f		\n"
  		"	mb			\n"
  		"	br	3f		\n"
  		"2:	br	1b		\n"
  		"3:				\n"
  		"	# END atomic_setbits_ulong"
  		: "=r" (t0), "=m" (*ulp)
  		: "r" (v), "1" (*ulp));
  #endif
  }
  
  /*
   * atomic_clearbits_ulong:
   *
   *	Atomically clear bits in a `unsigned long'.
   */
  static __inline void
  atomic_clearbits_ulong(__volatile unsigned long *ulp, unsigned long v)
  {
  #if 1
  	*ulp &= ~v;
  #else
  	unsigned long t0;
  
  	__asm __volatile(
  		"# BEGIN atomic_clearbits_ulong\n"
  		"1:	ldq_l	%0, %3		\n"
  		"	and	%0, %2, %0	\n"
  		"	stq_c	%0, %1		\n"
  		"	beq	%0, 2f		\n"
  		"	mb			\n"
  		"	br	3f		\n"
  		"2:	br	1b		\n"
  		"3:				\n"
  		"	# END atomic_clearbits_ulong"
  		: "=r" (t0), "=m" (*ulp)
  		: "r" (~v), "1" (*ulp));
  #endif
  }
  
  /*
   * atomic_add_ulong:
   *
   *	Atomically add a value to a `unsigned long'.
   */
  static __inline void
  atomic_add_ulong(__volatile unsigned long *ulp, unsigned long v)
  {
  	unsigned long t0;
  
  	__asm __volatile(
  		"# BEGIN atomic_add_ulong\n"
  		"1:	ldq_l	%0, %3		\n"
  		"	addq	%0, %2, %0	\n"
  		"	stq_c	%0, %1		\n"
  		"	beq	%0, 2f		\n"
  		"	mb			\n"
  		"	br	3f		\n"
  		"2:	br	1b		\n"
  		"3:				\n"
  		"	# END atomic_add_ulong"
  		: "=r" (t0), "=m" (*ulp)
  		: "r" (v), "1" (*ulp));
  }
  
  /*
   * atomic_sub_ulong:
   *
   *	Atomically subtract a value from a `unsigned long'.
   */
  static __inline void
  atomic_sub_ulong(__volatile unsigned long *ulp, unsigned long v)
  {
  	unsigned long t0;
  
  	__asm __volatile(
  		"# BEGIN atomic_sub_ulong\n"
  		"1:	ldq_l	%0, %3		\n"
  		"	subq	%0, %2, %0	\n"
  		"	stq_c	%0, %1		\n"
  		"	beq	%0, 2f		\n"
  		"	mb			\n"
  		"	br	3f		\n"
  		"2:	br	1b		\n"
  		"3:				\n"
  		"	# END atomic_sub_ulong"
  		: "=r" (t0), "=m" (*ulp)
  		: "r" (v), "1" (*ulp));
  }
  
  /*
   * atomic_loadlatch_ulong:
   *
   *	Atomically load and latch a `unsigned long' value.
   */
  static __inline unsigned long
  atomic_loadlatch_ulong(__volatile unsigned long *ulp, unsigned long v)
  {
  	unsigned long t0, v0;
  
  	__asm __volatile(
  		"# BEGIN atomic_loadlatch_ulong\n"
  		"1:	mov	%3, %0		\n"
  		"	ldq_l	%1, %4		\n"
  		"	stq_c	%0, %2		\n"
  		"	beq	%0, 2f		\n"
  		"	mb			\n"
  		"	br	3f		\n"
  		"2:	br	1b		\n"
  		"3:				\n"
  		"	# END atomic_loadlatch_ulong"
  		: "=r" (t0), "=r" (v0), "=m" (*ulp)
  		: "r" (v), "2" (*ulp));
  
  	return (v0);
  }
  
  #endif /* _ALPHA_ATOMIC_H_ */
  