时钟中断与控制动画速度问题

#include ...
#include ...

int timer = 0;

void myfunc()
{
     timer ? 0 : 1;
}

int main()
{
      int flag;
      .....
      .....

      allegro_init();
      install_keyboard();
      install_timer();

      install_init_ex(myfunc, BPS_TO_TIMER(30))       //每秒钟触发30次
      
      while(1)
      {
           if (key[KEY_A])
           {
                  if (flag != timer)
                  {
                        //动画移动
                        .............
                        flag = timer;
                  }                  
            }
            else if (key[KEY_ALT] & key[KEY_F4])
            {
                   //动画结束
                   .............
            }
      }
      ...........
      ...........
}