求注释,单片机按键程序

#include
#include
unsigned char scan_key();
void proc_key(unsigned char key_v);
void delayms(unsigned char ms);
sbit K1 = P0^0; //对应按钮K1
sbit K2 = P0^1; //对应按钮K2
main()
{
unsigned char key_s,key_v;
key_v = 0x03;
P2 = 0xfe;
while(1)
{
key_s = scan_key();
if(key_s != key_v)
{
delayms(10);
key_s = scan_key();
if(key_s != key_v)
{
key_v = key_s;
proc_key(key_v);
}
}
}
}
unsigned char scan_key()
{
unsigned char key_s;
key_s = 0x00;
key_s |= K2;
key_s <<= 1;
key_s |= K1;
return key_s;
}
void proc_key(unsigned char key_v)
{
if((key_v & 0x01) == 0)
{
P2 = _cror_(P2,1);
}
else if((key_v & 0x02) == 0)
{
P2 = _crol_(P2, 1);
}
}
void delayms(unsigned char ms) // 延时子程序
{
unsigned char i;
while(ms--)
{
for(i = 0; i < 120; i++);
}
}

main()
{
unsigned char key_s,key_v;
key_v = 0x03;
P2 = 0xfe;
while(1)
{
key_s = scan_key();
if(key_s != key_v) //两次键值不一样时表示有新按键，否则做抖动处理
{
delayms(10);
key_s = scan_key(); //延时10MS后再将一次键值
if(key_s != key_v) //确定是新键按下
{
key_v = key_s; //更新按键状态
proc_key(key_v); //根据键值完成相应动作
}
}
}
}

loop: jnb key1,tokey1 jnb key2,tokey2 jnb key3,tokey3 jnb key4,tokey4 . . . ljmp loop tokey1: lcall d10ms ;按键去抖动 jb key1,loop lcall display ;数码管扫描程序 ajmp loop