software Interrupt Service routine in C for windows operating system - c

Question

#include <stdio.h>
#include <time.h>
#include <windows.h>
void Task()
{
printf("Hi");
}
int main ( ) {
time_t t;
clock_t start, end;
long i;
long count;
double x = 0.0;
count = 2;
start = clock();
time(&t);
printf(ctime(&t));
printf( "Counting to %ld\n", count );
if(count)
{
Task();
}
end = clock();
printf( "That took %f seconds and I counted up to %ld", (((double)(end-start)/CLOCKS_PER_SEC)), count );
printf( "\nThat also took %d clock tics\n ", clock());
return 0;
}
I want to get the start time and end time taken to execute the Task function. I am trying to create interrupt for the Task function but displaying Hi in the program. I am not successful with that. So could you please anyone can guide me regarding this.

Answer 1

Try starting with the Multimedia Timers. Another possible approach might be using CreateTimerQueueTimer() and friends.

Answer 2

There is no way of having interrupts in user-mode, only kernel-mode drivers can service interrupt requests.
However you can have a callback function called by the OS in a periodic way. On Windows you can achieve this using the multimedia times (however declared obsolete by Microsoft) or timer queue timers (check this, for example: http://msdn.microsoft.com/en-us/library/windows/desktop/ms682485%28v=vs.85%29.aspx).
Here is an old test program I wrote that uses the Multimedia timers (obsolete but they still work on recent Windows versions...):
#include <stdio.h>
#include <windows.h>
volatile long timer = 0;
// Will be called every 1 ms
void CALLBACK timer_func(UINT uTimerID, UINT uMsg, DWORD *dwUser,
DWORD *dw1, DWORD *dw2)
{
timer++;
}
int main(int argc, char *argv[])
{
MMRESULT id = timeSetEvent(1, 0, (LPTIMECALLBACK) timer_func, NULL, TIME_PERIODIC);
printf("Waiting 10 seconds... ");
fflush(stdout);
Sleep(10000);
printf("ok. Timer = %ld.\n", timer);
timeKillEvent(id);
return 0;
}
If you just want to precisely measure how long a function call lasts, just use QueryPerformanceCounter() and QueryPerformanceFrequency():
#include <windows.h>
#include <stdio.h>
void task()
{
// do something...
}
int main()
{
LARGE_INTEGER start, stop, freq;
QueryPerformanceCounter(&start);
task();
QueryPerformanceCounter(&stop);
QueryPerformanceFrequency(&freq);
double time_len = (stop.QuadPart - start.QuadPart) / (double) freq.QuadPart;
printf("Task length: %0.8f seconds.\n", time_len);
}

Answer 3

New answer after discussion (see comments of my previous answer): you can implement an equivalent to the GetStopWatch() function you want this way:
#include <windows.h>
#include <stdio.h>
#include <stdint.h>
// assuming we return times with microsecond resolution
#define STOPWATCH_TICKS_PER_US 1
uint64_t GetStopWatch()
{
LARGE_INTEGER t, freq;
uint64_t val;
QueryPerformanceCounter(&t);
QueryPerformanceFrequency(&freq);
return (uint64_t) (t.QuadPart / (double) freq.QuadPart * 1000000);
}
void task()
{
// do something...
}
int main()
{
uint64_t start = GetStopWatch();
task();
uint64_t stop = GetStopWatch();
printf("Elapsed time (microseconds): %lld\n", stop - start);
}
Hope this helps.