nes-proj/arch/cpu/msp430/rtimer-arch.h

/*
 * Copyright (c) 2007, 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.
 *
 */

/**
 * \file
 *         Header file for the MSP430-specific rtimer code
 * \author
 *         Adam Dunkels <adam@sics.se>
 */

#ifndef RTIMER_ARCH_H_
#define RTIMER_ARCH_H_

#include "sys/rtimer.h"

#define RTIMER_ARCH_SECOND (4096U*8)

/* Do the math in 32bits to save precision.
 * Round to nearest integer rather than truncate. */
#define US_TO_RTIMERTICKS(US)  ((US) >= 0 ?                        \
                               (((int32_t)(US) * (RTIMER_ARCH_SECOND) + 500000) / 1000000L) :      \
                               ((int32_t)(US) * (RTIMER_ARCH_SECOND) - 500000) / 1000000L)

#define RTIMERTICKS_TO_US(T)   ((T) >= 0 ?                     \
                               (((int32_t)(T) * 1000000L + ((RTIMER_ARCH_SECOND) / 2)) / (RTIMER_ARCH_SECOND)) : \
                               ((int32_t)(T) * 1000000L - ((RTIMER_ARCH_SECOND) / 2)) / (RTIMER_ARCH_SECOND))

/* A 64-bit version because the 32-bit one cannot handle T >= 4295 ticks.
   Intended only for positive values of T. */
#define RTIMERTICKS_TO_US_64(T)  ((uint32_t)(((uint64_t)(T) * 1000000 + ((RTIMER_ARCH_SECOND) / 2)) / (RTIMER_ARCH_SECOND)))

rtimer_clock_t rtimer_arch_now(void);

#endif /* RTIMER_ARCH_H_ */