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      1 // Copyright (c) 2010, Atmel Corporation.
      2 // All rights reserved.
      3 //
      4 // Redistribution and use in source and binary forms, with or without
      5 // modification, are permitted provided that the following conditions are met:
      6 //     * Redistributions of source code must retain the above copyright
      7 //       notice, this list of conditions and the following disclaimer.
      8 //     * Redistributions in binary form must reproduce the above copyright
      9 //       notice, this list of conditions and the following disclaimer in the
     10 //       documentation and/or other materials provided with the distribution.
     11 //     * Neither the name of Atmel nor the
     12 //       names of its contributors may be used to endorse or promote products
     13 //       derived from this software without specific prior written permission.
     14 //
     15 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
     16 // ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
     17 // WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
     18 // DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE FOR ANY
     19 // DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
     20 // (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
     21 // LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
     22 // ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     23 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
     24 // SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     25 
     26 #include <stdint.h>
     27 #include "SHA_TimeUtils.h"
     28 
     29 
     30 // The values below are valid for an AVR 8-bit processor running at 16 MHz.
     31 // Code is compiled with -O1.
     32 
     33 //!< Offsets time needed to prepare microseconds loop.
     34 #define SHA_TIME_OFFSET_US      (7)
     35 
     36 //!< Fill a while loop with these CPU instructions to achieve 1 us per iteration.
     37 #define SHA_TIME_LOOP_FILLER    asm volatile ("nop\n\tnop\n\tnop\n\tnop\n\tnop\n\tnop\n\tnop")
     38 
     39 
     40 extern void SA_Delay(uint32_t delay);
     41 
     42 
     43 
     44 
     45 
     46 
     47 /** \brief Delays for a certain amount of time.
     48  *
     49  * \param[in] delay Delay for this number of microseconds (us).
     50  */
     51 void SHAP_Delay(uint32_t delay) {
     52     if (delay <= SHA_TIME_OFFSET_US)
     53         // We spent already this much time entering this function.
     54         // With other words: A value <= SHA_TIME_OFFSET_US will not produce the desired delay.
     55         return;
     56 
     57     delay -= SHA_TIME_OFFSET_US;
     58 
     59 
     60     SA_Delay(delay);
     61 
     62     return;
     63 }
     64 
     65 
     66 void loop_delay(int8_t multp) {
     67     int i, base = 2000000 *multp;
     68     for(i=0;i<base;i++) {
     69         double value = 10.0; //((i * 33.3) - 12.1) / 10.0;
     70         value += 1.0;
     71     }
     72 }
     73