spinlock.s
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上传日期:2007-06-06
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- // ***** BEGIN LICENSE BLOCK *****
- // Source last modified: $Id: spinlock.s,v 1.1 2003/08/03 21:55:06 dcollins Exp $
- //
- // Portions Copyright (c) 1995-2003 RealNetworks, Inc. All Rights Reserved.
- //
- // The contents of this file, and the files included with this file,
- // are subject to the current version of the RealNetworks Public
- // Source License (the "RPSL") available at
- // http://www.helixcommunity.org/content/rpsl unless you have licensed
- // the file under the current version of the RealNetworks Community
- // Source License (the "RCSL") available at
- // http://www.helixcommunity.org/content/rcsl, in which case the RCSL
- // will apply. You may also obtain the license terms directly from
- // RealNetworks. You may not use this file except in compliance with
- // the RPSL or, if you have a valid RCSL with RealNetworks applicable
- // to this file, the RCSL. Please see the applicable RPSL or RCSL for
- // the rights, obligations and limitations governing use of the
- // contents of the file.
- //
- // This file is part of the Helix DNA Technology. RealNetworks is the
- // developer of the Original Code and owns the copyrights in the
- // portions it created.
- //
- // This file, and the files included with this file, is distributed
- // and made available on an 'AS IS' basis, WITHOUT WARRANTY OF ANY
- // KIND, EITHER EXPRESS OR IMPLIED, AND REALNETWORKS HEREBY DISCLAIMS
- // ALL SUCH WARRANTIES, INCLUDING WITHOUT LIMITATION, ANY WARRANTIES
- // OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, QUIET
- // ENJOYMENT OR NON-INFRINGEMENT.
- //
- // Technology Compatibility Kit Test Suite(s) Location:
- // http://www.helixcommunity.org/content/tck
- //
- // Contributor(s):
- //
- // ***** END LICENSE BLOCK ***** */
- //////////////////////////////////////////////////////////////////////
- //
- // spinlock.s
- // Implements a test-and-set operator, for use with a spinlock.
- // implemented in IA64 (Itanium) assembly.
- //
- // Implementation Notes:
- // A work-in-progress....
- //
- //////////////////////////////////////////////////////////////////////
-
- //////////////////////////////////////////////////////////////////////
- // Misc. Assembler Directives
- //////////////////////////////////////////////////////////////////////
- .radix C // C-style numeric constants
- .section .text = "ax", "progbits" // read-only object code
- //////////////////////////////////////////////////////////////////////
- //
- // _HXMutexSetBit
- // atomic test-and-set operator
- //
- // Interface:
- // extern "C" int _HXMutexSetBit(HX_MUTEX pLock);
- //
- // Inputs:
- // Paramaters:
- // in0 : HX_MUTEX pLock - pointer to mutex (integer) to modify
- //
- // Outputs:
- // Atomically modifies memory at *pLock:
- // *pLock = 1
- //
- // Return value:
- // r8 : UINT32 - previous value of *pLock
- // If zero, the lock attempt was successful
- //
- //////////////////////////////////////////////////////////////////////
- .proc _HXMutexSetBit
- .global _HXMutexSetBit
- _HXMutexSetBit:
- alloc loc0 = ar.pfs, 1, 1, 0, 0 //one input, one local
- mov r8 = 1;; //x = 1
- xchg4 r8 = [in0], r8;; //swap *pLock and x
- br.ret.dptk.few rp;; //return previous *pLock value
- .endp _HXMutexSetBit
- //////////////////////////////////////////////////////////////////////
- //
- // _HXMutexClearBit
- // atomic bit clear operator
- //
- // Interface:
- // extern "C" void _HXMutexClearBit(HX_MUTEX pLock);
- //
- // Inputs:
- // Paramaters:
- // in0 : HX_MUTEX pLock - pointer to mutex (integer) to modify
- //
- // Outputs:
- // Atomically modifies memory at *pLock:
- // *pLock = 0
- //
- // Return value:
- // none
- //
- //////////////////////////////////////////////////////////////////////
- //
- // Implementation notes:
- // We cannot safely just set the lock to zero with an assignment, the
- // use of the st4.rel release semantics is necessary to enforce correct
- // memory ordering.
- //
- //////////////////////////////////////////////////////////////////////
- .proc _HXMutexClearBit
- .global _HXMutexClearBit
- _HXMutexClearBit:
- alloc loc0 = ar.pfs, 1, 1, 0, 0 //one input, one local
- st4.rel [in0] = r0;; //atomically set to zero
- br.ret.dptk.few rp;; //return
- .endp _HXMutexClearBit