lock_byte.s

英特尔&#174 线程构建模块（英特尔&#174 TBB）是一个屡获殊荣的 C++ 运行时库

// Copyright 2005-2007 Intel Corporation.  All Rights Reserved.
//
// This file is part of Threading Building Blocks.
//
// Threading Building Blocks 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.
//
// Threading Building Blocks 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 Threading Building Blocks; if not, write to the Free Software
// Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
//
// As a special exception, you may use this file as part of a free software
// library without restriction.  Specifically, if other files instantiate
// templates or use macros or inline functions from this file, or you compile
// this file and link it with other files to produce an executable, this
// file does not by itself cause the resulting executable to be covered by
// the GNU General Public License.  This exception does not however
// invalidate any other reasons why the executable file might be covered by
// the GNU General Public License.

	// Support for class TinyLock
	.section .text
	.align 16
	// unsigned int __TBB_machine_trylockbyte( byte& flag );
	// r32 = address of flag 
	.proc  __TBB_machine_trylockbyte#
	.global __TBB_machine_trylockbyte#
ADDRESS_OF_FLAG=r32
RETCODE=r8
FLAG=r9
BUSY=r10
SCRATCH=r11
__TBB_machine_trylockbyte:
        ld1.acq FLAG=[ADDRESS_OF_FLAG]
        mov BUSY=1
        mov RETCODE=0
;;
        cmp.ne p6,p0=0,FLAG
        mov ar.ccv=r0
(p6)    br.ret.sptk.many b0
;;
        cmpxchg1.acq SCRATCH=[ADDRESS_OF_FLAG],BUSY,ar.ccv  // Try to acquire lock
;;
        cmp.eq p6,p0=0,SCRATCH
;;
(p6)    mov RETCODE=1
   	br.ret.sptk.many b0	
	.endp __TBB_TryLockByte#