//==========================================================================
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//==========================================================================
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//
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//
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// sync/bin_sem.cxx
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// sync/bin_sem.cxx
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//
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//
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// Binary semaphore implementation
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// Binary semaphore implementation
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//
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//
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//==========================================================================
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//==========================================================================
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//####ECOSGPLCOPYRIGHTBEGIN####
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//####ECOSGPLCOPYRIGHTBEGIN####
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// -------------------------------------------
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// -------------------------------------------
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// This file is part of eCos, the Embedded Configurable Operating System.
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// This file is part of eCos, the Embedded Configurable Operating System.
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// Copyright (C) 1998, 1999, 2000, 2001, 2002 Red Hat, Inc.
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// Copyright (C) 1998, 1999, 2000, 2001, 2002 Red Hat, Inc.
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//
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//
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// eCos is free software; you can redistribute it and/or modify it under
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// eCos is free software; you can redistribute it and/or modify it under
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// the terms of the GNU General Public License as published by the Free
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// the terms of the GNU General Public License as published by the Free
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// Software Foundation; either version 2 or (at your option) any later version.
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// Software Foundation; either version 2 or (at your option) any later version.
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//
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//
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// eCos is distributed in the hope that it will be useful, but WITHOUT ANY
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// eCos is distributed in the hope that it will be useful, but WITHOUT ANY
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// WARRANTY; without even the implied warranty of MERCHANTABILITY or
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// WARRANTY; without even the implied warranty of MERCHANTABILITY or
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// FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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// FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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// for more details.
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// for more details.
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//
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//
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// You should have received a copy of the GNU General Public License along
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// You should have received a copy of the GNU General Public License along
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// with eCos; if not, write to the Free Software Foundation, Inc.,
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// with eCos; if not, write to the Free Software Foundation, Inc.,
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// 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
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// 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
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//
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//
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// As a special exception, if other files instantiate templates or use macros
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// As a special exception, if other files instantiate templates or use macros
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// or inline functions from this file, or you compile this file and link it
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// or inline functions from this file, or you compile this file and link it
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// with other works to produce a work based on this file, this file does not
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// with other works to produce a work based on this file, this file does not
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// by itself cause the resulting work to be covered by the GNU General Public
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// by itself cause the resulting work to be covered by the GNU General Public
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// License. However the source code for this file must still be made available
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// License. However the source code for this file must still be made available
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// in accordance with section (3) of the GNU General Public License.
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// in accordance with section (3) of the GNU General Public License.
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//
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//
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// This exception does not invalidate any other reasons why a work based on
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// This exception does not invalidate any other reasons why a work based on
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// this file might be covered by the GNU General Public License.
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// this file might be covered by the GNU General Public License.
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//
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//
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// Alternative licenses for eCos may be arranged by contacting Red Hat, Inc.
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// Alternative licenses for eCos may be arranged by contacting Red Hat, Inc.
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// at http://sources.redhat.com/ecos/ecos-license/
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// at http://sources.redhat.com/ecos/ecos-license/
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// -------------------------------------------
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// -------------------------------------------
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//####ECOSGPLCOPYRIGHTEND####
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//####ECOSGPLCOPYRIGHTEND####
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//==========================================================================
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//==========================================================================
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//#####DESCRIPTIONBEGIN####
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//#####DESCRIPTIONBEGIN####
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//
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//
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// Author(s): nickg
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// Author(s): nickg
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// Contributors: nickg
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// Contributors: nickg
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// Date: 1997-09-24
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// Date: 1997-09-24
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// Purpose: Cyg_Binary_Semaphore implementation
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// Purpose: Cyg_Binary_Semaphore implementation
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// Description: This file contains the implementations of the binary semaphore
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// Description: This file contains the implementations of the binary semaphore
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// class.
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// class.
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//
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//
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//####DESCRIPTIONEND####
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//####DESCRIPTIONEND####
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//
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//
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//==========================================================================
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//==========================================================================
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#include <pkgconf/kernel.h>
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#include <pkgconf/kernel.h>
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#include <cyg/kernel/ktypes.h> // base kernel types
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#include <cyg/kernel/ktypes.h> // base kernel types
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#include <cyg/infra/cyg_trac.h> // tracing macros
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#include <cyg/infra/cyg_trac.h> // tracing macros
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#include <cyg/infra/cyg_ass.h> // assertion macros
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#include <cyg/infra/cyg_ass.h> // assertion macros
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#include <cyg/kernel/instrmnt.h> // instrumentation
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#include <cyg/kernel/instrmnt.h> // instrumentation
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#include <cyg/kernel/thread.inl> // Cyg_Thread inlines
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#include <cyg/kernel/thread.inl> // Cyg_Thread inlines
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#include <cyg/kernel/sema.hxx> // our header
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#include <cyg/kernel/sema.hxx> // our header
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#include <cyg/kernel/sched.inl> // scheduler inlines
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#include <cyg/kernel/sched.inl> // scheduler inlines
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// -------------------------------------------------------------------------
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// -------------------------------------------------------------------------
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Cyg_Binary_Semaphore::Cyg_Binary_Semaphore (
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Cyg_Binary_Semaphore::Cyg_Binary_Semaphore (
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cyg_bool init_state
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cyg_bool init_state
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)
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)
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{
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{
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state = init_state;
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state = init_state;
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}
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}
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// -------------------------------------------------------------------------
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// -------------------------------------------------------------------------
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Cyg_Binary_Semaphore::~Cyg_Binary_Semaphore ( )
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Cyg_Binary_Semaphore::~Cyg_Binary_Semaphore ( )
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{
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{
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}
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}
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// -------------------------------------------------------------------------
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// -------------------------------------------------------------------------
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cyg_bool Cyg_Binary_Semaphore::wait()
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cyg_bool Cyg_Binary_Semaphore::wait()
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{
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{
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cyg_bool result = true;
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cyg_bool result = true;
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Cyg_Thread *self = Cyg_Thread::self();
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Cyg_Thread *self = Cyg_Thread::self();
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// Prevent preemption
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// Prevent preemption
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Cyg_Scheduler::lock();
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Cyg_Scheduler::lock();
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CYG_INSTRUMENT_BINSEM( CLAIM, this, state );
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CYG_INSTRUMENT_BINSEM( CLAIM, this, state );
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while( !state && result )
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while( !state && result )
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{
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{
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self->set_sleep_reason( Cyg_Thread::WAIT );
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self->set_sleep_reason( Cyg_Thread::WAIT );
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self->sleep();
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self->sleep();
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queue.enqueue( self );
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queue.enqueue( self );
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CYG_INSTRUMENT_BINSEM( WAIT, this, 0 );
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CYG_INSTRUMENT_BINSEM( WAIT, this, 0 );
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// Allow other threads to run
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// Allow other threads to run
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Cyg_Scheduler::reschedule();
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Cyg_Scheduler::reschedule();
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CYG_INSTRUMENT_BINSEM( WOKE, this, state );
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CYG_INSTRUMENT_BINSEM( WOKE, this, state );
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switch( self->get_wake_reason() )
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switch( self->get_wake_reason() )
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{
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{
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case Cyg_Thread::DESTRUCT:
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case Cyg_Thread::DESTRUCT:
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case Cyg_Thread::BREAK:
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case Cyg_Thread::BREAK:
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result = false;
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result = false;
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break;
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break;
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case Cyg_Thread::EXIT:
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case Cyg_Thread::EXIT:
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self->exit();
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self->exit();
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break;
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break;
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default:
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default:
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break;
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break;
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}
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}
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}
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}
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if( result ) state = false;
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if( result ) state = false;
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// Unlock the scheduler and maybe switch threads
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// Unlock the scheduler and maybe switch threads
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Cyg_Scheduler::unlock();
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Cyg_Scheduler::unlock();
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return result;
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return result;
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}
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}
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// -------------------------------------------------------------------------
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// -------------------------------------------------------------------------
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cyg_bool Cyg_Binary_Semaphore::trywait()
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cyg_bool Cyg_Binary_Semaphore::trywait()
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{
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{
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cyg_bool result = true;
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cyg_bool result = true;
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// Prevent preemption
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// Prevent preemption
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Cyg_Scheduler::lock();
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Cyg_Scheduler::lock();
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if( state ) state = false;
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if( state ) state = false;
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else result = false;
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else result = false;
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CYG_INSTRUMENT_BINSEM( TRY, this, result );
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CYG_INSTRUMENT_BINSEM( TRY, this, result );
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// Unlock the scheduler and maybe switch threads
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// Unlock the scheduler and maybe switch threads
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Cyg_Scheduler::unlock();
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Cyg_Scheduler::unlock();
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return result;
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return result;
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}
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}
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// -------------------------------------------------------------------------
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// -------------------------------------------------------------------------
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void Cyg_Binary_Semaphore::post()
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void Cyg_Binary_Semaphore::post()
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{
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{
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// Prevent preemption
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// Prevent preemption
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Cyg_Scheduler::lock();
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Cyg_Scheduler::lock();
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CYG_INSTRUMENT_BINSEM( POST, this, 0 );
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CYG_INSTRUMENT_BINSEM( POST, this, 0 );
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state = true;
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state = true;
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if( !queue.empty() ) {
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if( !queue.empty() ) {
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// The queue is non-empty, so grab the next
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// The queue is non-empty, so grab the next
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// thread from it and wake it up. The waiter
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// thread from it and wake it up. The waiter
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// will clear the flag.
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// will clear the flag.
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Cyg_Thread *thread = queue.dequeue();
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Cyg_Thread *thread = queue.dequeue();
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thread->set_wake_reason( Cyg_Thread::DONE );
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thread->set_wake_reason( Cyg_Thread::DONE );
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thread->wake();
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thread->wake();
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CYG_INSTRUMENT_BINSEM( WAKE, this, thread );
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CYG_INSTRUMENT_BINSEM( WAKE, this, thread );
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}
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}
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// Unlock the scheduler and maybe switch threads
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// Unlock the scheduler and maybe switch threads
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Cyg_Scheduler::unlock();
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Cyg_Scheduler::unlock();
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}
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}
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// -------------------------------------------------------------------------
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// -------------------------------------------------------------------------
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cyg_bool Cyg_Binary_Semaphore::posted()
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cyg_bool Cyg_Binary_Semaphore::posted()
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{
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{
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// This is a single read of the value of state.
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// This is a single read of the value of state.
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// This is already atomic, hence there is no need
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// This is already atomic, hence there is no need
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// to lock the scheduler.
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// to lock the scheduler.
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return state;
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return state;
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}
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}
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// -------------------------------------------------------------------------
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// -------------------------------------------------------------------------
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// EOF sync/bin_sem.cxx
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// EOF sync/bin_sem.cxx
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