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! BEGIN COPYRIGHT BLOCK
! This Program is free software; you can redistribute it and/or modify it under
! the terms of the GNU General Public License as published by the Free Software
! Foundation; version 2 of the License.
!
! This 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 Program; if not, write to the Free Software Foundation, Inc., 59 Temple
! Place, Suite 330, Boston, MA 02111-1307 USA.
!
! In addition, as a special exception, Red Hat, Inc. gives You the additional
! right to link the code of this Program with code not covered under the GNU
! General Public License ("Non-GPL Code") and to distribute linked combinations
! including the two, subject to the limitations in this paragraph. Non-GPL Code
! permitted under this exception must only link to the code of this Program
! through those well defined interfaces identified in the file named EXCEPTION
! found in the source code files (the "Approved Interfaces"). The files of
! Non-GPL Code may instantiate templates or use macros or inline functions from
! the Approved Interfaces without causing the resulting work to be covered by
! the GNU General Public License. Only Red Hat, Inc. may make changes or
! additions to the list of Approved Interfaces. You must obey the GNU General
! Public License in all respects for all of the Program code and other code used
! in conjunction with the Program except the Non-GPL Code covered by this
! exception. If you modify this file, you may extend this exception to your
! version of the file, but you are not obligated to do so. If you do not wish to
! provide this exception without modification, you must delete this exception
! statement from your version and license this file solely under the GPL without
! exception.
!
!
! The Original Code is the Netscape Portable Runtime (NSPR).
!
! The Initial Developer of the Original Code is
! Netscape Communications Corporation.
! Portions created by the Initial Developer are Copyright (C) 1998-2000
! the Initial Developer. All Rights Reserved.
!
! The original code has been modified to support 64-bit atomic increments by
! Red Hat, Inc. These portions are Copyright (C) 2008 Red Hat, Inc. All Rights
! reserved.
!
! END COPYRIGHT BLOCK
!
#define _ASM 1 /* force to set an assembler code macro _ASM */
#include <sys/asm_linkage.h>
! ======================================================================
!
! Perform the sequence a = b atomically with respect to other
! fetch-and-stores to location a in a wait-free fashion.
!
! usage : old_val = PR_AtomicSet(address, newval)
!
! -----------------------
! Note on REGISTER USAGE:
! as this is a LEAF procedure, a new stack frame is not created;
! we use the caller's stack frame so what would normally be %i (input)
! registers are actually %o (output registers). Also, we must not
! overwrite the contents of %l (local) registers as they are not
! assumed to be volatile during calls.
! -----------------------
ENTRY(_sparcv9_AtomicSet) ! standard assembler/ELF prologue
retryAS:
ldx [%o0], %o2 ! set o2 to the current value
mov %o1, %o3 ! set up the new value
casx [%o0], %o2, %o3 ! atomically set if o0 hasn't changed
cmp %o2, %o3 ! see if we set the value
bne retryAS ! if not, try again
nop ! empty out the branch pipeline
retl ! return back to the caller
mov %o3, %o0 ! set the return code to the prev value
SET_SIZE(_sparcv9_AtomicSet) ! standard assembler/ELF epilogue
!
! end
!
! ======================================================================
!
! Perform the sequence a = a + b atomically with respect to other
! fetch-and-adds to location a in a wait-free fashion.
!
! usage : newval = PR_AtomicAdd(address, val)
! return: the value after addition
!
ENTRY(_sparcv9_AtomicAdd) ! standard assembler/ELF prologue
retryAA:
ldx [%o0], %o2 ! set o2 to the current value
addx %o2, %o1, %o3 ! calc the new value
mov %o3, %o4 ! save the return value
casx [%o0], %o2, %o3 ! atomically set if o0 hasn't changed
cmp %o2, %o3 ! see if we set the value
bne retryAA ! if not, try again
nop ! empty out the branch pipeline
retl ! return back to the caller
mov %o4, %o0 ! set the return code to the new value
SET_SIZE(_sparcv9_AtomicAdd) ! standard assembler/ELF epilogue
!
! end
!
! ======================================================================
!
! Perform the sequence a = a - b atomically with respect to other
! fetch-and-subs to location a in a wait-free fashion.
!
! usage : newval = PR_AtomicSub(address, val)
! return: the value after addition
!
ENTRY(_sparcv9_AtomicSub) ! standard assembler/ELF prologue
retryAU:
ldx [%o0], %o2 ! set o2 to the current value
subx %o2, %o1, %o3 ! calc the new value
mov %o3, %o4 ! save the return value
casx [%o0], %o2, %o3 ! atomically set if o0 hasn't changed
cmp %o2, %o3 ! see if we set the value
bne retryAU ! if not, try again
nop ! empty out the branch pipeline
retl ! return back to the caller
mov %o4, %o0 ! set the return code to the new value
SET_SIZE(_sparcv9_AtomicSub) ! standard assembler/ELF epilogue
!
! end
!
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