对下面的程序进行代码效率分析:

void Delay(void)
{
    unsigned char a, b;
    for (a =1;a;a++)
        for (b =1;b;b++)
            ;
}

void LED_On(int i)
{
    PORTB=~(1<<i);
    Delay();
}

void main(void)
{
    int i;
    MCUCR=0x00;
    DDRB =0xFF;
    PORTB =0xFF;
    while (1)
    {
        for (i =0;i <8;i++)
            LED_On(i);
        for (i =8;i >0;i--)
            LED_On(i);
        for (i =0;i <8;i +=2)
            LED_On(i);
        for (i =7;i >0;i -=2)
            LED_On(i);
     }
}

对一个浮点运算程序进行代码速度分析:

void main(void)
{
    float x,y,z;
    x = 1.0;
    y = 2.0;
    z = sin(x+y);
}