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 <[email protected]> 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 <[email protected]> 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 /** @} */ 84