97 lines
3.3 KiB
C
97 lines
3.3 KiB
C
/*
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* Copyright (c) 2015, SICS Swedish ICT.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the Institute nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* This file is part of the Contiki operating system.
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*
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*/
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/**
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* \file
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* TSCH 5-Byte Absolute Slot Number (ASN) management
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* \author
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* Simon Duquennoy <simonduq@sics.se>
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*
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*/
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#ifndef __TSCH_ASN_H__
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#define __TSCH_ASN_H__
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/************ Types ***********/
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/* The ASN is an absolute slot number over 5 bytes. */
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struct asn_t {
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uint32_t ls4b; /* least significant 4 bytes */
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uint8_t ms1b; /* most significant 1 byte */
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};
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/* For quick modulo operation on ASN */
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struct asn_divisor_t {
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uint16_t val; /* Divisor value */
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uint16_t asn_ms1b_remainder; /* Remainder of the operation 0x100000000 / val */
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};
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/************ Macros **********/
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/* Initialize ASN */
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#define ASN_INIT(asn, ms1b_, ls4b_) do { \
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(asn).ms1b = (ms1b_); \
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(asn).ls4b = (ls4b_); \
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} while(0);
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/* Increment an ASN by inc (32 bits) */
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#define ASN_INC(asn, inc) do { \
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uint32_t new_ls4b = (asn).ls4b + (inc); \
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if(new_ls4b < (asn).ls4b) { (asn).ms1b++; } \
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(asn).ls4b = new_ls4b; \
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} while(0);
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/* Decrement an ASN by inc (32 bits) */
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#define ASN_DEC(asn, dec) do { \
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uint32_t new_ls4b = (asn).ls4b - (dec); \
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if(new_ls4b > (asn).ls4b) { (asn).ms1b--; } \
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(asn).ls4b = new_ls4b; \
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} while(0);
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/* Returns the 32-bit diff between asn1 and asn2 */
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#define ASN_DIFF(asn1, asn2) \
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((asn1).ls4b - (asn2).ls4b)
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/* Initialize a struct asn_divisor_t */
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#define ASN_DIVISOR_INIT(div, val_) do { \
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(div).val = (val_); \
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(div).asn_ms1b_remainder = ((0xffffffff % (val_)) + 1) % (val_); \
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} while(0);
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/* Returns the result (16 bits) of a modulo operation on ASN,
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* with divisor being a struct asn_divisor_t */
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#define ASN_MOD(asn, div) \
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((uint16_t)((asn).ls4b % (div).val) \
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+ (uint16_t)((asn).ms1b * (div).asn_ms1b_remainder % (div).val)) \
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% (div).val
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#endif /* __TSCH_ASN_H__ */
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