Homework2_3Multithreads_YuwenSun

Dependencies:   mbed

Files at this revision

API Documentation at this revision

Comitter:
sun831011
Date:
Tue Nov 30 22:19:29 2010 +0000
Commit message:

Changed in this revision

lc-addrlabels.h Show annotated file Show diff for this revision Revisions of this file
lc-switch.h Show annotated file Show diff for this revision Revisions of this file
lc.h Show annotated file Show diff for this revision Revisions of this file
main.cpp Show annotated file Show diff for this revision Revisions of this file
mbed.bld Show annotated file Show diff for this revision Revisions of this file
pt-sem.h Show annotated file Show diff for this revision Revisions of this file
pt.h Show annotated file Show diff for this revision Revisions of this file
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lc-addrlabels.h	Tue Nov 30 22:19:29 2010 +0000
@@ -0,0 +1,85 @@
+/*
+ * Copyright (c) 2004-2005, Swedish Institute of Computer Science.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. 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.
+ * 3. Neither the name of the Institute 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 INSTITUTE 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 INSTITUTE 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.
+ *
+ * This file is part of the Contiki operating system.
+ *
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ * $Id: lc-addrlabels.h,v 1.4 2006/06/03 11:29:43 adam Exp $
+ */
+
+/**
+ * \addtogroup lc
+ * @{
+ */
+
+/**
+ * \file
+ * Implementation of local continuations based on the "Labels as
+ * values" feature of gcc
+ * \author
+ * Adam Dunkels <adam@sics.se>
+ *
+ * This implementation of local continuations is based on a special
+ * feature of the GCC C compiler called "labels as values". This
+ * feature allows assigning pointers with the address of the code
+ * corresponding to a particular C label.
+ *
+ * For more information, see the GCC documentation:
+ * http://gcc.gnu.org/onlinedocs/gcc/Labels-as-Values.html
+ *
+ */
+
+#ifndef __LC_ADDRLABELS_H__
+#define __LC_ADDRLABELS_H__
+
+/** \hideinitializer */
+typedef void * lc_t;
+
+#define LC_INIT(s) s = NULL
+
+#define LC_RESUME(s)				\
+  do {						\
+    if(s != NULL) {				\
+      goto *s;					\
+    }						\
+  } while(0)
+
+#define LC_CONCAT2(s1, s2) s1##s2
+#define LC_CONCAT(s1, s2) LC_CONCAT2(s1, s2)
+
+#define LC_SET(s)				\
+  do {						\
+    LC_CONCAT(LC_LABEL, __LINE__):   	        \
+    (s) = &&LC_CONCAT(LC_LABEL, __LINE__);	\
+  } while(0)
+
+#define LC_END(s)
+
+#endif /* __LC_ADDRLABELS_H__ */
+/** @} */
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lc-switch.h	Tue Nov 30 22:19:29 2010 +0000
@@ -0,0 +1,76 @@
+/*
+ * Copyright (c) 2004-2005, Swedish Institute of Computer Science.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. 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.
+ * 3. Neither the name of the Institute 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 INSTITUTE 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 INSTITUTE 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.
+ *
+ * This file is part of the Contiki operating system.
+ *
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ * $Id: lc-switch.h,v 1.4 2006/06/03 11:29:43 adam Exp $
+ */
+
+/**
+ * \addtogroup lc
+ * @{
+ */
+
+/**
+ * \file
+ * Implementation of local continuations based on switch() statment
+ * \author Adam Dunkels <adam@sics.se>
+ *
+ * This implementation of local continuations uses the C switch()
+ * statement to resume execution of a function somewhere inside the
+ * function's body. The implementation is based on the fact that
+ * switch() statements are able to jump directly into the bodies of
+ * control structures such as if() or while() statmenets.
+ *
+ * This implementation borrows heavily from Simon Tatham's coroutines
+ * implementation in C:
+ * http://www.chiark.greenend.org.uk/~sgtatham/coroutines.html
+ */
+
+#ifndef __LC_SWITCH_H__
+#define __LC_SWITCH_H__
+
+/* WARNING! lc implementation using switch() does not work if an
+   LC_SET() is done within another switch() statement! */
+
+/** \hideinitializer */
+typedef unsigned short lc_t;
+
+#define LC_INIT(s) s = 0;
+
+#define LC_RESUME(s) switch(s) { case 0:
+
+#define LC_SET(s) s = __LINE__; case __LINE__:
+
+#define LC_END(s) }
+
+#endif /* __LC_SWITCH_H__ */
+
+/** @} */
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lc.h	Tue Nov 30 22:19:29 2010 +0000
@@ -0,0 +1,132 @@
+/*
+ * Copyright (c) 2004-2005, Swedish Institute of Computer Science.
+ * All rights reserved. 
+ *
+ * Redistribution and use in source and binary forms, with or without 
+ * modification, are permitted provided that the following conditions 
+ * are met: 
+ * 1. Redistributions of source code must retain the above copyright 
+ *    notice, this list of conditions and the following disclaimer. 
+ * 2. 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. 
+ * 3. Neither the name of the Institute 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 INSTITUTE 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 INSTITUTE 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. 
+ *
+ * This file is part of the protothreads library.
+ * 
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ * $Id: lc.h,v 1.2 2005/02/24 10:36:59 adam Exp $
+ */
+
+/**
+ * \addtogroup pt
+ * @{
+ */
+
+/**
+ * \defgroup lc Local continuations
+ * @{
+ *
+ * Local continuations form the basis for implementing protothreads. A
+ * local continuation can be <i>set</i> in a specific function to
+ * capture the state of the function. After a local continuation has
+ * been set can be <i>resumed</i> in order to restore the state of the
+ * function at the point where the local continuation was set.
+ *
+ *
+ */
+
+/**
+ * \file lc.h
+ * Local continuations
+ * \author
+ * Adam Dunkels <adam@sics.se>
+ *
+ */
+
+#ifdef DOXYGEN
+/**
+ * Initialize a local continuation.
+ *
+ * This operation initializes the local continuation, thereby
+ * unsetting any previously set continuation state.
+ *
+ * \hideinitializer
+ */
+#define LC_INIT(lc)
+
+/**
+ * Set a local continuation.
+ *
+ * The set operation saves the state of the function at the point
+ * where the operation is executed. As far as the set operation is
+ * concerned, the state of the function does <b>not</b> include the
+ * call-stack or local (automatic) variables, but only the program
+ * counter and such CPU registers that needs to be saved.
+ *
+ * \hideinitializer
+ */
+#define LC_SET(lc)
+
+/**
+ * Resume a local continuation.
+ *
+ * The resume operation resumes a previously set local continuation, thus
+ * restoring the state in which the function was when the local
+ * continuation was set. If the local continuation has not been
+ * previously set, the resume operation does nothing.
+ *
+ * \hideinitializer
+ */
+#define LC_RESUME(lc)
+
+/**
+ * Mark the end of local continuation usage.
+ *
+ * The end operation signifies that local continuations should not be
+ * used any more in the function. This operation is not needed for
+ * most implementations of local continuation, but is required by a
+ * few implementations.
+ *
+ * \hideinitializer 
+ */
+#define LC_END(lc)
+
+/**
+ * \var typedef lc_t;
+ *
+ * The local continuation type.
+ *
+ * \hideinitializer
+ */
+#endif /* DOXYGEN */
+
+#ifndef __LC_H__
+#define __LC_H__
+
+
+#ifdef LC_INCLUDE
+#include LC_INCLUDE
+#else
+#include "lc-switch.h"
+#endif /* LC_INCLUDE */
+
+#endif /* __LC_H__ */
+
+/** @} */
+/** @} */
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Tue Nov 30 22:19:29 2010 +0000
@@ -0,0 +1,214 @@
+#include "mbed.h"
+#include "lc.h"
+#include "pt-sem.h"
+#include "pt.h"
+
+#define numsamples 1
+int touchSense1(void);  //function for the button 1
+
+DigitalOut myled1(LED1);
+AnalogIn input1(p20);
+DigitalIn charger1(p19);
+DigitalOut ground1(p18);
+Serial pc(USBTX, USBRX); // tx, rx
+
+int touchSense2(void);  //function for the button 2
+
+DigitalOut myled2(LED4);
+AnalogIn input2(p15);
+DigitalIn charger2(p16);
+DigitalOut ground2(p17);
+  
+char incode[10];
+char strcode[10];
+char matcode[10];
+char temp;
+int codelen = 1;
+int matlen;
+int i=0;
+int j=0;
+int flag1 = 0;
+int flag2 = 0;
+int failflag = 0;
+
+int protothread1_flag, protothread2_flag;
+static struct pt pt1, pt2;
+
+
+static int protothread1(struct pt *pt){
+
+    PT_BEGIN(pt);
+
+    while(1) {
+
+        PT_WAIT_UNTIL(pt, protothread2_flag != 0);
+
+        if (pc.readable()){
+            protothread2_flag = 0;
+            protothread1_flag = 1;
+        }
+
+       if (touchSense1()) { 
+           wait (0.005);    //wait 5ms for checking press
+            if (touchSense1()){
+                myled1 = 1;
+                if (flag1 == 0){
+                    flag1 =1;   //flag1 for symbol press
+                    pc.printf("1");
+                    matcode[matlen] = '1'; //record for compare
+                    matlen ++;
+                }
+            }
+         
+       } else {
+            wait(0.005);  //wait 5ms confirm release
+            if (touchSense1()==0){
+                myled1 = 0;
+                flag1 = 0; //clear flag
+            }
+        }
+    
+        if (touchSense2()) { //samiliar as above 1
+            wait (0.005);
+            if (touchSense2()){
+                myled2 = 1;
+                if (flag2 == 0){
+                    flag2 =1;
+                    pc.printf("0");
+                    matcode[matlen] = '0';
+                    matlen ++;
+                }
+            }
+         
+        } else {
+            wait(0.005);
+            if (touchSense2()==0){
+                myled2 = 0;
+                flag2 = 0;
+            }
+        }
+    
+        if (flag1 == 1 && flag2 == 1){ //detect press both button
+            pc.printf("\nError, please don't touch both!!");
+            //break;
+        }
+    
+        if (matlen >= codelen){ //check input length match the set up
+            for (i=0;i<codelen;i++){
+                if (matcode[i] != strcode[i])
+                    failflag = 1; //flag for symbol not match
+            }
+        
+            if (failflag == 0){
+                pc.printf("\n Congratulations! Code is matched!!\n");
+                matlen = 0;
+            
+            }
+        
+            else{
+                pc.printf("\nSorry, the code is wrong, please input again!!\n");
+                failflag = 0;
+                matlen = 0;
+            }
+        
+       }
+   }
+
+
+PT_END(pt);
+}
+
+
+
+static int protothread2(struct pt *pt) {
+
+    PT_BEGIN(pt);
+    while(1) {
+
+        protothread2_flag = 1;
+        PT_WAIT_UNTIL(pt, protothread1_flag != 0);
+
+        i=0;
+        j=0;
+        pc.printf("\nPlease inpunt the code:\n");
+        while ((temp = pc.getc())!= 'E') {    //getchar
+            pc.printf("%c",temp);
+            incode[i] = temp;    //put the original char in incode      
+            i++;
+        }    
+  
+        incode[i] = 'E'; //put "E" last as the end symbol
+        pc.printf("%c",temp);
+        pc.printf("\nThanks for the string, your input is\n");
+  
+        for (i=0;i<10;i++){   //extract 0/1 from incode to strcode
+            if (incode[i] == 'E')
+                break;
+            else{
+                if (incode[i] == '0' || incode[i] == '1'){
+                    strcode[j] = incode[i];
+                    j++;
+                }
+            }
+        
+        }
+  
+        codelen = j;
+  
+        for (j=0;j<codelen;j++)   //display the configuration
+            pc.printf("%c",strcode[j]);
+        pc.printf("\n");
+  
+        matlen = 0;  
+  
+        pc.printf("\nPlease input the code:");
+
+        protothread1_flag = 0;
+
+    }
+PT_END(pt);
+}
+
+
+int main()
+{
+  for (i=0;i<10;i++){   //initial the char array
+    incode[i] = 'a';    
+    strcode[i] = 'a';
+  }
+    
+  PT_INIT(&pt1);
+  PT_INIT(&pt2);
+
+  while(1) {
+  protothread1(&pt1);
+  protothread2(&pt2);
+  }
+}
+
+int touchSense1(void) //function for touch sensor
+{
+    float sample;
+    ground1 = 0;
+    charger1.mode(PullUp);
+    charger1.mode(PullNone);
+    sample=input1.read();
+    if (sample < 0.3) {
+        return 1;
+    } else {
+        return 0;
+    }
+}
+int touchSense2(void)
+{
+    float sample;
+    ground2 = 0;
+    charger2.mode(PullUp);
+    charger2.mode(PullNone);
+    sample=input2.read();
+    if (sample < 0.3) {
+        return 1;
+    } else {
+        return 0;
+    }
+}
\ No newline at end of file
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mbed.bld	Tue Nov 30 22:19:29 2010 +0000
@@ -0,0 +1,1 @@
+http://mbed.org/users/mbed_official/code/mbed/builds/e2ac27c8e93e
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/pt-sem.h	Tue Nov 30 22:19:29 2010 +0000
@@ -0,0 +1,228 @@
+/*
+ * Copyright (c) 2004, Swedish Institute of Computer Science.
+ * All rights reserved. 
+ *
+ * Redistribution and use in source and binary forms, with or without 
+ * modification, are permitted provided that the following conditions 
+ * are met: 
+ * 1. Redistributions of source code must retain the above copyright 
+ *    notice, this list of conditions and the following disclaimer. 
+ * 2. 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. 
+ * 3. Neither the name of the Institute 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 INSTITUTE 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 INSTITUTE 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. 
+ *
+ * This file is part of the protothreads library.
+ * 
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ * $Id: pt-sem.h,v 1.2 2005/02/24 10:36:59 adam Exp $
+ */
+
+/**
+ * \addtogroup pt
+ * @{
+ */
+
+/**
+ * \defgroup ptsem Protothread semaphores
+ * @{
+ *
+ * This module implements counting semaphores on top of
+ * protothreads. Semaphores are a synchronization primitive that
+ * provide two operations: "wait" and "signal". The "wait" operation
+ * checks the semaphore counter and blocks the thread if the counter
+ * is zero. The "signal" operation increases the semaphore counter but
+ * does not block. If another thread has blocked waiting for the
+ * semaphore that is signalled, the blocked thread will become
+ * runnable again.
+ *
+ * Semaphores can be used to implement other, more structured,
+ * synchronization primitives such as monitors and message
+ * queues/bounded buffers (see below).
+ *
+ * The following example shows how the producer-consumer problem, also
+ * known as the bounded buffer problem, can be solved using
+ * protothreads and semaphores. Notes on the program follow after the
+ * example.
+ *
+ \code
+#include "pt-sem.h"
+
+#define NUM_ITEMS 32
+#define BUFSIZE 8
+
+static struct pt_sem mutex, full, empty;
+
+PT_THREAD(producer(struct pt *pt))
+{
+  static int produced;
+  
+  PT_BEGIN(pt);
+  
+  for(produced = 0; produced < NUM_ITEMS; ++produced) {
+  
+    PT_SEM_WAIT(pt, &full);
+    
+    PT_SEM_WAIT(pt, &mutex);
+    add_to_buffer(produce_item());    
+    PT_SEM_SIGNAL(pt, &mutex);
+    
+    PT_SEM_SIGNAL(pt, &empty);
+  }
+
+  PT_END(pt);
+}
+
+PT_THREAD(consumer(struct pt *pt))
+{
+  static int consumed;
+  
+  PT_BEGIN(pt);
+
+  for(consumed = 0; consumed < NUM_ITEMS; ++consumed) {
+    
+    PT_SEM_WAIT(pt, &empty);
+    
+    PT_SEM_WAIT(pt, &mutex);    
+    consume_item(get_from_buffer());    
+    PT_SEM_SIGNAL(pt, &mutex);
+    
+    PT_SEM_SIGNAL(pt, &full);
+  }
+
+  PT_END(pt);
+}
+
+PT_THREAD(driver_thread(struct pt *pt))
+{
+  static struct pt pt_producer, pt_consumer;
+
+  PT_BEGIN(pt);
+  
+  PT_SEM_INIT(&empty, 0);
+  PT_SEM_INIT(&full, BUFSIZE);
+  PT_SEM_INIT(&mutex, 1);
+
+  PT_INIT(&pt_producer);
+  PT_INIT(&pt_consumer);
+
+  PT_WAIT_THREAD(pt, producer(&pt_producer) &
+		     consumer(&pt_consumer));
+
+  PT_END(pt);
+}
+ \endcode
+ *
+ * The program uses three protothreads: one protothread that
+ * implements the consumer, one thread that implements the producer,
+ * and one protothread that drives the two other protothreads. The
+ * program uses three semaphores: "full", "empty" and "mutex". The
+ * "mutex" semaphore is used to provide mutual exclusion for the
+ * buffer, the "empty" semaphore is used to block the consumer is the
+ * buffer is empty, and the "full" semaphore is used to block the
+ * producer is the buffer is full.
+ *
+ * The "driver_thread" holds two protothread state variables,
+ * "pt_producer" and "pt_consumer". It is important to note that both
+ * these variables are declared as <i>static</i>. If the static
+ * keyword is not used, both variables are stored on the stack. Since
+ * protothreads do not store the stack, these variables may be
+ * overwritten during a protothread wait operation. Similarly, both
+ * the "consumer" and "producer" protothreads declare their local
+ * variables as static, to avoid them being stored on the stack.
+ * 
+ *
+ */
+   
+/**
+ * \file
+ * Couting semaphores implemented on protothreads
+ * \author
+ * Adam Dunkels <adam@sics.se>
+ *
+ */
+
+#ifndef __PT_SEM_H__
+#define __PT_SEM_H__
+
+#include "pt.h"
+
+struct pt_sem {
+  unsigned int count;
+};
+
+/**
+ * Initialize a semaphore
+ *
+ * This macro initializes a semaphore with a value for the
+ * counter. Internally, the semaphores use an "unsigned int" to
+ * represent the counter, and therefore the "count" argument should be
+ * within range of an unsigned int.
+ *
+ * \param s (struct pt_sem *) A pointer to the pt_sem struct
+ * representing the semaphore
+ *
+ * \param c (unsigned int) The initial count of the semaphore.
+ * \hideinitializer
+ */
+#define PT_SEM_INIT(s, c) (s)->count = c
+
+/**
+ * Wait for a semaphore
+ *
+ * This macro carries out the "wait" operation on the semaphore. The
+ * wait operation causes the protothread to block while the counter is
+ * zero. When the counter reaches a value larger than zero, the
+ * protothread will continue.
+ *
+ * \param pt (struct pt *) A pointer to the protothread (struct pt) in
+ * which the operation is executed.
+ *
+ * \param s (struct pt_sem *) A pointer to the pt_sem struct
+ * representing the semaphore
+ *
+ * \hideinitializer
+ */
+#define PT_SEM_WAIT(pt, s)	\
+  do {						\
+    PT_WAIT_UNTIL(pt, (s)->count > 0);		\
+    --(s)->count;				\
+  } while(0)
+
+/**
+ * Signal a semaphore
+ *
+ * This macro carries out the "signal" operation on the semaphore. The
+ * signal operation increments the counter inside the semaphore, which
+ * eventually will cause waiting protothreads to continue executing.
+ *
+ * \param pt (struct pt *) A pointer to the protothread (struct pt) in
+ * which the operation is executed.
+ *
+ * \param s (struct pt_sem *) A pointer to the pt_sem struct
+ * representing the semaphore
+ *
+ * \hideinitializer
+ */
+#define PT_SEM_SIGNAL(pt, s) ++(s)->count
+
+#endif /* __PT_SEM_H__ */
+
+/** @} */
+/** @} */
+   
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/pt.h	Tue Nov 30 22:19:29 2010 +0000
@@ -0,0 +1,323 @@
+/*
+ * Copyright (c) 2004-2005, Swedish Institute of Computer Science.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. 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.
+ * 3. Neither the name of the Institute 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 INSTITUTE 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 INSTITUTE 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.
+ *
+ * This file is part of the Contiki operating system.
+ *
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ * $Id: pt.h,v 1.7 2006/10/02 07:52:56 adam Exp $
+ */
+
+/**
+ * \addtogroup pt
+ * @{
+ */
+
+/**
+ * \file
+ * Protothreads implementation.
+ * \author
+ * Adam Dunkels <adam@sics.se>
+ *
+ */
+
+#ifndef __PT_H__
+#define __PT_H__
+
+#include "lc.h"
+
+struct pt {
+  lc_t lc;
+};
+
+#define PT_WAITING 0
+#define PT_YIELDED 1
+#define PT_EXITED  2
+#define PT_ENDED   3
+
+/**
+ * \name Initialization
+ * @{
+ */
+
+/**
+ * Initialize a protothread.
+ *
+ * Initializes a protothread. Initialization must be done prior to
+ * starting to execute the protothread.
+ *
+ * \param pt A pointer to the protothread control structure.
+ *
+ * \sa PT_SPAWN()
+ *
+ * \hideinitializer
+ */
+#define PT_INIT(pt)   LC_INIT((pt)->lc)
+
+/** @} */
+
+/**
+ * \name Declaration and definition
+ * @{
+ */
+
+/**
+ * Declaration of a protothread.
+ *
+ * This macro is used to declare a protothread. All protothreads must
+ * be declared with this macro.
+ *
+ * \param name_args The name and arguments of the C function
+ * implementing the protothread.
+ *
+ * \hideinitializer
+ */
+#define PT_THREAD(name_args) char name_args
+
+/**
+ * Declare the start of a protothread inside the C function
+ * implementing the protothread.
+ *
+ * This macro is used to declare the starting point of a
+ * protothread. It should be placed at the start of the function in
+ * which the protothread runs. All C statements above the PT_BEGIN()
+ * invokation will be executed each time the protothread is scheduled.
+ *
+ * \param pt A pointer to the protothread control structure.
+ *
+ * \hideinitializer
+ */
+#define PT_BEGIN(pt) { char PT_YIELD_FLAG = 1; LC_RESUME((pt)->lc)
+
+/**
+ * Declare the end of a protothread.
+ *
+ * This macro is used for declaring that a protothread ends. It must
+ * always be used together with a matching PT_BEGIN() macro.
+ *
+ * \param pt A pointer to the protothread control structure.
+ *
+ * \hideinitializer
+ */
+#define PT_END(pt) LC_END((pt)->lc); PT_YIELD_FLAG = 0; \
+                   PT_INIT(pt); return PT_ENDED; }
+
+/** @} */
+
+/**
+ * \name Blocked wait
+ * @{
+ */
+
+/**
+ * Block and wait until condition is true.
+ *
+ * This macro blocks the protothread until the specified condition is
+ * true.
+ *
+ * \param pt A pointer to the protothread control structure.
+ * \param condition The condition.
+ *
+ * \hideinitializer
+ */
+#define PT_WAIT_UNTIL(pt, condition)	        \
+  do {						\
+    LC_SET((pt)->lc);				\
+    if(!(condition)) {				\
+      return PT_WAITING;			\
+    }						\
+  } while(0)
+
+/**
+ * Block and wait while condition is true.
+ *
+ * This function blocks and waits while condition is true. See
+ * PT_WAIT_UNTIL().
+ *
+ * \param pt A pointer to the protothread control structure.
+ * \param cond The condition.
+ *
+ * \hideinitializer
+ */
+#define PT_WAIT_WHILE(pt, cond)  PT_WAIT_UNTIL((pt), !(cond))
+
+/** @} */
+
+/**
+ * \name Hierarchical protothreads
+ * @{
+ */
+
+/**
+ * Block and wait until a child protothread completes.
+ *
+ * This macro schedules a child protothread. The current protothread
+ * will block until the child protothread completes.
+ *
+ * \note The child protothread must be manually initialized with the
+ * PT_INIT() function before this function is used.
+ *
+ * \param pt A pointer to the protothread control structure.
+ * \param thread The child protothread with arguments
+ *
+ * \sa PT_SPAWN()
+ *
+ * \hideinitializer
+ */
+#define PT_WAIT_THREAD(pt, thread) PT_WAIT_WHILE((pt), PT_SCHEDULE(thread))
+
+/**
+ * Spawn a child protothread and wait until it exits.
+ *
+ * This macro spawns a child protothread and waits until it exits. The
+ * macro can only be used within a protothread.
+ *
+ * \param pt A pointer to the protothread control structure.
+ * \param child A pointer to the child protothread's control structure.
+ * \param thread The child protothread with arguments
+ *
+ * \hideinitializer
+ */
+#define PT_SPAWN(pt, child, thread)		\
+  do {						\
+    PT_INIT((child));				\
+    PT_WAIT_THREAD((pt), (thread));		\
+  } while(0)
+
+/** @} */
+
+/**
+ * \name Exiting and restarting
+ * @{
+ */
+
+/**
+ * Restart the protothread.
+ *
+ * This macro will block and cause the running protothread to restart
+ * its execution at the place of the PT_BEGIN() call.
+ *
+ * \param pt A pointer to the protothread control structure.
+ *
+ * \hideinitializer
+ */
+#define PT_RESTART(pt)				\
+  do {						\
+    PT_INIT(pt);				\
+    return PT_WAITING;			\
+  } while(0)
+
+/**
+ * Exit the protothread.
+ *
+ * This macro causes the protothread to exit. If the protothread was
+ * spawned by another protothread, the parent protothread will become
+ * unblocked and can continue to run.
+ *
+ * \param pt A pointer to the protothread control structure.
+ *
+ * \hideinitializer
+ */
+#define PT_EXIT(pt)				\
+  do {						\
+    PT_INIT(pt);				\
+    return PT_EXITED;			\
+  } while(0)
+
+/** @} */
+
+/**
+ * \name Calling a protothread
+ * @{
+ */
+
+/**
+ * Schedule a protothread.
+ *
+ * This function shedules a protothread. The return value of the
+ * function is non-zero if the protothread is running or zero if the
+ * protothread has exited.
+ *
+ * \param f The call to the C function implementing the protothread to
+ * be scheduled
+ *
+ * \hideinitializer
+ */
+#define PT_SCHEDULE(f) ((f) < PT_EXITED)
+
+/** @} */
+
+/**
+ * \name Yielding from a protothread
+ * @{
+ */
+
+/**
+ * Yield from the current protothread.
+ *
+ * This function will yield the protothread, thereby allowing other
+ * processing to take place in the system.
+ *
+ * \param pt A pointer to the protothread control structure.
+ *
+ * \hideinitializer
+ */
+#define PT_YIELD(pt)				\
+  do {						\
+    PT_YIELD_FLAG = 0;				\
+    LC_SET((pt)->lc);				\
+    if(PT_YIELD_FLAG == 0) {			\
+      return PT_YIELDED;			\
+    }						\
+  } while(0)
+
+/**
+ * \brief      Yield from the protothread until a condition occurs.
+ * \param pt   A pointer to the protothread control structure.
+ * \param cond The condition.
+ *
+ *             This function will yield the protothread, until the
+ *             specified condition evaluates to true.
+ *
+ *
+ * \hideinitializer
+ */
+#define PT_YIELD_UNTIL(pt, cond)		\
+  do {						\
+    PT_YIELD_FLAG = 0;				\
+    LC_SET((pt)->lc);				\
+    if((PT_YIELD_FLAG == 0) || !(cond)) {	\
+      return PT_YIELDED;			\
+    }						\
+  } while(0)
+
+/** @} */
+
+#endif /* __PT_H__ */
+
+/** @} */