performance_test.c

   1 /*
   2  *
   3  *
   4  *
   5  */
   6
   7 #include <stdint.h>
   8 #include <stdlib.h>
   9 #include <avr/io.h>
  10 #include <avr/interrupt.h>
  11 #include "performance_test.h"
  12
  13 uint32_t ovfcounter;
  14
  15 uint16_t const_overhead=0;
  16 uint16_t int_overhead=0;
  17
  18 ISR(TIMER1_OVF_vect){
  19         ovfcounter++;
  20 }
  21
  22 void calibrateTimer(void){
  23         startTimer(1);
  24         stopTimer();
  25         const_overhead = TCNT1;
  26         startTimer(1);
  27         TCNT1=0xFFFE;
  28         ; ; ; ;
  29 //      asm volatile("NOP\n"::); asm volatile("NOP\n"::);
  30         stopTimer();
  31         int_overhead = TCNT1;
  32 }
  33
  34 void startTimer(uint8_t granularity){
  35         TCCR1B = 0; /* stop timer */
  36         TCNT1  = 0;
  37         ovfcounter = 0;
  38         TCCR1A = 0x00;
  39         TIMSK &= 0xC3;
  40         TIMSK |= _BV(2); /* enable TOIE1 */
  41         TCCR1B = granularity & 0x7;     /* start timer */
  42 }
  43
  44 uint64_t stopTimer(void){
  45         TCCR1B = 0; /* stop timer */
  46         uint64_t ret;
  47         ret = (ovfcounter<<16) | TCNT1;
  48         ret -= const_overhead;
  49         ret -= ovfcounter * int_overhead;
  50         return ret;
  51 }
  52
  53 void getOverhead(uint16_t* constoh, uint16_t* intoh){
  54         *constoh = const_overhead;
  55         *intoh   = int_overhead;
  56 }
  57
  58
  59
  60