single_interrupt.c

#include <stdio.h>
#include <string.h>
#include <stdint.h>

uint32_t THE_STATUS_REGISTER = 0;

typedef void (*handler) (void);

typedef struct {
  handler  hdl;
  uint32_t mask;
} HandlerEntry_T;

HandlerEntry_T handlers[16];

void init(void);
void single_interrupt(void);
void register_handler(handler hdl, uint32_t mask);

void handler_1(void);
void handler_2(void);
void handler_3(void);

void init(void)
{
  memset(handlers, 0, sizeof(handlers));

  register_handler(handler_1, 0x00000001);
  register_handler(handler_2, 0x00000002);
  register_handler(handler_3, 0x00000004);
}

void single_interrupt(void)
{
  int i;

  for (i = 0; i < sizeof(handlers) / sizeof(HandlerEntry_T); i++)
  {
    if (handlers[i].mask & THE_STATUS_REGISTER)
    {
      handlers[i].hdl();
    }
  }
}

void register_handler(handler hdl, uint32_t mask)
{
  int i;

  for (i = 0; i < sizeof(handlers) / sizeof(HandlerEntry_T); i++)
  {
    if (0 == handlers[i].hdl)
    {
      handlers[i].hdl = hdl;
      handlers[i].mask = mask;
      break;
    }
  }
}

void handler_1(void)
{
  printf("Handler 1!\n");
}

void handler_2(void)
{
  printf("Handler 2!\n");
}

void handler_3(void)
{
  printf("Handler 3!\n");
}

int main(int argc, char * argv[])
{
  init();

  THE_STATUS_REGISTER = 1;
  single_interrupt();
  THE_STATUS_REGISTER = 2;
  single_interrupt();
  THE_STATUS_REGISTER = 4;
  single_interrupt();
  THE_STATUS_REGISTER = 1 | 2 | 4;
  single_interrupt();

  return 0;
}

$ ./single_interrupt
Handler 1!
Handler 2!
Handler 3!
Handler 1!
Handler 2!
Handler 3!