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//$Id: BusyWaitCounterC.nc,v 1.5 2010-06-29 22:07:50 scipio Exp $
/* Copyright (c) 2000-2003 The Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* - Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the
* distribution.
* - Neither the name of the copyright holders nor the names of
* its contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
* THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "Timer.h"
/**
* BusyWaitCounterC uses a Counter to implement the BusyWait interface
* (block until a specified amount of time elapses). See TEP102 for more
* details.
*
* <p>See TEP102 for more details.
*
* @param precision_tag A type indicating the precision of the BusyWait
* interface.
* @param size_type An integer type representing time values for the
* BusyWait interface.
*
* @author Cory Sharp <cssharp@eecs.berkeley.edu>
*/
generic module BusyWaitCounterC(typedef precision_tag, typedef size_type @integer())
{
provides interface BusyWait<precision_tag,size_type>;
uses interface Counter<precision_tag,size_type>;
}
implementation
{
enum
{
HALF_MAX_SIZE_TYPE = ((size_type)1) << (8*sizeof(size_type)-1),
};
async command void BusyWait.wait(size_type dt)
{
atomic
{
// comparisons are <= to guarantee a wait at least as long as dt
size_type t0 = call Counter.get();
if(dt > HALF_MAX_SIZE_TYPE)
{
dt -= HALF_MAX_SIZE_TYPE;
while((call Counter.get() - t0) <= dt);
t0 += dt;
dt = HALF_MAX_SIZE_TYPE;
}
while((call Counter.get() - t0) <= dt);
}
}
async event void Counter.overflow()
{
}
}
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