URL
https://opencores.org/ocsvn/openrisc/openrisc/trunk
Subversion Repositories openrisc
[/] [openrisc/] [trunk/] [rtos/] [ecos-2.0/] [packages/] [kernel/] [v2_0/] [src/] [sync/] [bin_sem.cxx] - Rev 234
Go to most recent revision | Compare with Previous | Blame | View Log
//========================================================================== // // sync/bin_sem.cxx // // Binary semaphore implementation // //========================================================================== //####ECOSGPLCOPYRIGHTBEGIN#### // ------------------------------------------- // This file is part of eCos, the Embedded Configurable Operating System. // Copyright (C) 1998, 1999, 2000, 2001, 2002 Red Hat, Inc. // // eCos 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; either version 2 or (at your option) any later version. // // eCos 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 eCos; if not, write to the Free Software Foundation, Inc., // 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. // // As a special exception, if other files instantiate templates or use macros // or inline functions from this file, or you compile this file and link it // with other works to produce a work based on this file, this file does not // by itself cause the resulting work to be covered by the GNU General Public // License. However the source code for this file must still be made available // in accordance with section (3) of the GNU General Public License. // // This exception does not invalidate any other reasons why a work based on // this file might be covered by the GNU General Public License. // // Alternative licenses for eCos may be arranged by contacting Red Hat, Inc. // at http://sources.redhat.com/ecos/ecos-license/ // ------------------------------------------- //####ECOSGPLCOPYRIGHTEND#### //========================================================================== //#####DESCRIPTIONBEGIN#### // // Author(s): nickg // Contributors: nickg // Date: 1997-09-24 // Purpose: Cyg_Binary_Semaphore implementation // Description: This file contains the implementations of the binary semaphore // class. // //####DESCRIPTIONEND#### // //========================================================================== #include <pkgconf/kernel.h> #include <cyg/kernel/ktypes.h> // base kernel types #include <cyg/infra/cyg_trac.h> // tracing macros #include <cyg/infra/cyg_ass.h> // assertion macros #include <cyg/kernel/instrmnt.h> // instrumentation #include <cyg/kernel/thread.inl> // Cyg_Thread inlines #include <cyg/kernel/sema.hxx> // our header #include <cyg/kernel/sched.inl> // scheduler inlines // ------------------------------------------------------------------------- Cyg_Binary_Semaphore::Cyg_Binary_Semaphore ( cyg_bool init_state ) { state = init_state; } // ------------------------------------------------------------------------- Cyg_Binary_Semaphore::~Cyg_Binary_Semaphore ( ) { } // ------------------------------------------------------------------------- cyg_bool Cyg_Binary_Semaphore::wait() { cyg_bool result = true; Cyg_Thread *self = Cyg_Thread::self(); // Prevent preemption Cyg_Scheduler::lock(); CYG_INSTRUMENT_BINSEM( CLAIM, this, state ); while( !state && result ) { self->set_sleep_reason( Cyg_Thread::WAIT ); self->sleep(); queue.enqueue( self ); CYG_INSTRUMENT_BINSEM( WAIT, this, 0 ); // Allow other threads to run Cyg_Scheduler::reschedule(); CYG_INSTRUMENT_BINSEM( WOKE, this, state ); switch( self->get_wake_reason() ) { case Cyg_Thread::DESTRUCT: case Cyg_Thread::BREAK: result = false; break; case Cyg_Thread::EXIT: self->exit(); break; default: break; } } if( result ) state = false; // Unlock the scheduler and maybe switch threads Cyg_Scheduler::unlock(); return result; } // ------------------------------------------------------------------------- cyg_bool Cyg_Binary_Semaphore::trywait() { cyg_bool result = true; // Prevent preemption Cyg_Scheduler::lock(); if( state ) state = false; else result = false; CYG_INSTRUMENT_BINSEM( TRY, this, result ); // Unlock the scheduler and maybe switch threads Cyg_Scheduler::unlock(); return result; } // ------------------------------------------------------------------------- void Cyg_Binary_Semaphore::post() { // Prevent preemption Cyg_Scheduler::lock(); CYG_INSTRUMENT_BINSEM( POST, this, 0 ); state = true; if( !queue.empty() ) { // The queue is non-empty, so grab the next // thread from it and wake it up. The waiter // will clear the flag. Cyg_Thread *thread = queue.dequeue(); thread->set_wake_reason( Cyg_Thread::DONE ); thread->wake(); CYG_INSTRUMENT_BINSEM( WAKE, this, thread ); } // Unlock the scheduler and maybe switch threads Cyg_Scheduler::unlock(); } // ------------------------------------------------------------------------- cyg_bool Cyg_Binary_Semaphore::posted() { // This is a single read of the value of state. // This is already atomic, hence there is no need // to lock the scheduler. return state; } // ------------------------------------------------------------------------- // EOF sync/bin_sem.cxx
Go to most recent revision | Compare with Previous | Blame | View Log