FreeRTOS/Common/ethernet/FreeRTOS-uIP/lc-addrlabels.h

   1 /*
   2  * Copyright (c) 2004-2005, Swedish Institute of Computer Science.
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. Neither the name of the Institute nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  *
  29  * This file is part of the uIP TCP/IP stack
  30  *
  31  * Author: Adam Dunkels <adam@sics.se>
  32  *
  33  * $Id: lc-addrlabels.h,v 1.3 2006/06/12 08:00:30 adam Exp $
  34  */
  35
  36 /**
  37  * \addtogroup lc
  38  * @{
  39  */
  40
  41 /**
  42  * \file
  43  * Implementation of local continuations based on the "Labels as
  44  * values" feature of gcc
  45  * \author
  46  * Adam Dunkels <adam@sics.se>
  47  *
  48  * This implementation of local continuations is based on a special
  49  * feature of the GCC C compiler called "labels as values". This
  50  * feature allows assigning pointers with the address of the code
  51  * corresponding to a particular C label.
  52  *
  53  * For more information, see the GCC documentation:
  54  * http://gcc.gnu.org/onlinedocs/gcc/Labels-as-Values.html
  55  *
  56  * Thanks to dividuum for finding the nice local scope label
  57  * implementation.
  58  */
  59
  60 #ifndef __LC_ADDRLABELS_H__
  61 #define __LC_ADDRLABELS_H__
  62
  63 /** \hideinitializer */
  64 typedef void * lc_t;
  65
  66 #define LC_INIT(s) s = NULL
  67
  68
  69 #define LC_RESUME(s)                            \
  70   do {                                          \
  71     if(s != NULL) {                             \
  72       goto *s;                                  \
  73     }                                           \
  74   } while(0)
  75
  76 #define LC_SET(s)                               \
  77   do { ({ __label__ resume; resume: (s) = &&resume; }); }while(0)
  78
  79 #define LC_END(s)
  80
  81 #endif /* __LC_ADDRLABELS_H__ */
  82
  83 /**  @} */