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1 jermar 1
/*
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 * Copyright (C) 2001-2004 Jakub Jermar
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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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 *
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 * - 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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 * - 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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 * - The name of the author may not be used to endorse or promote products
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 *   derived from this software without specific prior written permission.
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 *
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 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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 */
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/** @addtogroup time
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 * @{
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 */
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/**
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 * @file
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 * @brief   Active delay function.
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 */
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#include <time/delay.h>
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#include <arch/types.h>
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#include <cpu.h>
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#include <arch/asm.h>
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#include <arch.h>
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/** Active delay
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 *
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 * Delay the execution for the given number
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 * of microseconds (or slightly more). The delay
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 * is implemented as CPU calibrated active loop.
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 *
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 * @param usec Number of microseconds to sleep.
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 */
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void delay(uint32_t usec)
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{
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    ipl_t ipl;
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    /*
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     * The delay loop is calibrated for each and every
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     * CPU in the system. Therefore it is necessary to
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     * call interrupts_disable() before calling the
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     * asm_delay_loop().
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     */
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    ipl = interrupts_disable();
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    asm_delay_loop(usec * CPU->delay_loop_const);
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    interrupts_restore(ipl);
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}
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/** @}
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 */