/*
* ========== Copyright Header Begin ==========================================
* 
* OpenSPARC T2 Processor File: barrier_subr_v8.s
* Copyright (c) 2006 Sun Microsystems, Inc.  All Rights Reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES.
* 
* The above named program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public
* License version 2 as published by the Free Software Foundation.
* 
* The above named program is distributed in the hope that it will be 
* useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
* General Public License for more details.
* 
* You should have received a copy of the GNU General Public
* License along with this work; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
* 
* ========== Copyright Header End ============================================
*/
#pragma ident "@(#)1.2	02/05/23	barrier_subr_v8.s"

#include <sys/asm_linkage.h>

#if 0 
	
	ENTRY(barrier)
	ld	[%o0 + 20], %o1			! load bp->sbp into %o1
	! atomic decrement of running count
	add	%o1, 4, %o2
retry:	ld	[%o2], %o3
	add	%o3, -1, %o4
	cas	[%o2], %o3, %o4
	cmp	%o3, %o4
	bne	retry
	nop
	
	! check if this is the last one
	cmp	%o3, 1
	bne	wait
	nop

	! YES, switch sub-barriers, reset count and CV
	add	%o0, 4, %o2			! %o2 = &bp->sb[0]
	cmp	%o1, %o2
	bne	1f
	nop
	add	%o0, 12, %o2			! %o2 = &bp->sb[1]
1:	st	%o2, [%o0 + 20]			! store %o2 into bp->sbp
	set	1, %o4
	st	%o4, [%o2]
	ld	[%o0], %o3
	st	%o3, [%o2 + 4]

	! release the CV busy-waiters
	retl
	clr	[%o1]

	! NO, busy-wait on CV
wait:	ld	[%o1], %o2
	tst	%o2
	bne	wait
	nop
	retl
	nop
	SET_SIZE(barrier)

#else 

	.global cpu_barrier
	ENTRY(barrier)
	or       %o0, 0, %o5                    ! loopticks
	set     cpu_barrier, %o0	
	ld	[%o0 + 20], %o1			! load bp->sbp into %o1
        ld	[%o0 + 24], %o0                 !!!!!! global tick pointer
		
	! atomic decrement of running count
	add	%o1, 4, %o2
retry:	ld	[%o2], %o3
	add	%o3, -1, %o4
	cas	[%o2], %o3, %o4
	cmp	%o3, %o4
	bne	retry
	nop

retry1:	ldx     [%o0], %o2           !!
	add     %o2, %o5, %o4        !!
	casx    [%o0], %o2, %o4      !!
	cmp     %o2, %o4             !!
	bne,pn  %xcc, retry1                   
	nop                          !!
	
	! check if this is the last one
	cmp	%o3, 1
	bne	wait
	nop

	! YES, switch sub-barriers, reset count and CV
	set     cpu_barrier, %o0		
	add	%o0, 4, %o2			! %o2 = &bp->sb[0]
	cmp	%o1, %o2
	bne	1f
	nop
	add	%o0, 12, %o2			! %o2 = &bp->sb[1]
1:	st	%o2, [%o0 + 20]			! store %o2 into bp->sbp
	set	1, %o4
	st	%o4, [%o2]
	ld	[%o0], %o3
	st	%o3, [%o2 + 4]

	! release the CV busy-waiters
	retl
	clr	[%o1]

	! NO, busy-wait on CV
wait:	ld	[%o1], %o2
	tst	%o2
	bne	wait
	nop
	retl
	nop
	SET_SIZE(barrier)


	
#endif