/*
 * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
 * 
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this
 * file.
 * 
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */
 /*
 * Copyright (c) 1997-1998 Apple Computer, Inc.
 *
 *
 * HISTORY
 *
 * sdouglas  22 Oct 97 - first checked in from DriverServices
 * sdouglas  28 Jul 98 - start IOKit
 */

#include <architecture/ppc/asm_help.h>

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;
; ENTRY		functionName
;
; Assembly directives to begin an exported function.
;
; Takes: functionName - name of the exported function
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

.macro ENTRY
	.text
	.align		2
	.globl		$0
$0:
.endmacro

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

/*
int OSCompareAndSwap( UInt32 oldVal, UInt32 newVal, UInt32 * addr )
*/


	ENTRY	_OSCompareAndSwap
.L_CASretry:
		lwz		r6,0(r5)		// Get the swap value
		cmpw	r6,r3			// Is is the same
		bne--	.L_CASfail2		// No...
		
.L_CASretry2:
		lwarx	r6,0,r5			// Get it atomically now
		cmpw	r6,r3			// Same?
		bne--	.L_CASfail		// Nope, go say so and toss reservations...
		stwcx.	r4,0,r5			// Stash the new value
		bne--	.L_CASretry2	// Just got collision...
		isync
		li	r3,	1
		blr

.L_CASfail:
		li		a7,-4			// Point to a spot in the red zone
		stwcx.	a7,a7,r1		// Kill reservation
		
.L_CASfail2:	
		li	r3,	0
		blr


/*
SInt32	OSDecrementAtomic(SInt32 * value)
*/
	ENTRY	_OSDecrementAtomic
	mr	r4, r3
	li	r3, -1
	b	_OSAddAtomic

/*
SInt32	OSIncrementAtomic(SInt32 * value)
*/

	ENTRY	_OSIncrementAtomic
	mr	r4, r3
	li	r3, 1

/*
SInt32	OSAddAtomic(SInt32 amount, SInt32 * value)
*/

	ENTRY	_OSAddAtomic

	mr	r5,r3				/* Save the increment */
.L_AAretry:
	lwarx	r3, 0, r4			/* Grab the area value */
	add	r6, r3, r5			/* Add the value */
	stwcx.	r6, 0, r4			/* Try to save the new value */
	bne-	.L_AAretry			/* Didn't get it, try again... */
	blr					/* Return the original value */