年轻时编程没学好，现在老了只好求助于AI

这是豆包编程给出的代码。我已经没有能力读懂了。
#include <reg51.h>
// 定义输入端口
sbit P20 = P2^0;
sbit P21 = P2^1;
sbit P22 = P2^2;
sbit P23 = P2^3;
sbit P24 = P2^4;
sbit P25 = P2^5;
// 定义输出端口
sbit P10 = P1^0;
sbit P11 = P1^1;
sbit P12 = P1^2;
sbit P13 = P1^3;
sbit P14 = P1^4;
sbit P15 = P1^5;
sbit P16 = P1^6;
// 定时器0中断服务函数，用于产生时钟信号
void timer0_isr() interrupt 1 {
static unsigned int count_10khz = 0;
static unsigned int count_1khz = 0;
static unsigned int count_100hz = 0;
static unsigned int count_5hz = 0;
static unsigned int count_1hz = 0;
// 10KHZ时钟信号
if (++count_10khz >= 5) {
P10 =!P10;
count_10khz = 0;
}
// 1KHZ时钟信号
if (++count_1khz >= 50) {
P11 =!P11;
count_1khz = 0;
}
// 100HZ时钟信号
if (++count_100hz >= 500) {
P12 =!P12;
count_100hz = 0;
}
// 5HZ时钟信号
if (++count_5hz >= 10000) {
P13 =!P13;
count_5hz = 0;
}
// 1HZ矩形波信号，占空比25%
if (++count_1hz >= 120000) {
P14 =!P14;
if (P14) {
count_1hz = -360000;
}
}
}
// 延时函数，用于产生单脉冲信号
void delay_ms(unsigned int ms) {
unsigned int i, j;
for (i = 0; i < ms; i++) {
for (j = 0; j < 123; j++);
}
}
// 主函数
void main() {
// 初始化定时器0
TMOD = 0x01;
TH0 = (65536 - 10) / 256;
TL0 = (65536 - 10) % 256;
ET0 = 1;
EA = 1;
TR0 = 1;
// 上电初始化
P10 = 0;
P11 = 0;
P12 = 0;
P13 = 0;
P14 = 0;
P15 = 1;
delay_ms(10);
P15 = 0;
while (1) {
// P20或P21有输入时
if ((P20 && P20 != 0) || (P21 == 0&& P21 != 1)) {
P14 = 0;
}
// P22或P23有输入时
if ((P22 && P22 != 0) || (P23 == 0&& P23 != 1)) {
P14 = 0;
}
// P24有输入时
if (P24 == 0) {
P15 = 1;
delay_ms(10);
P15 = 0;
while (P24 == 0); // 等待按键释放
}
// P25有输入时
if (P25 == 0) {
P16 = 1;
delay_ms(10);
P16 = 0;
while (P25 == 0); // 等待按键释放
}
}
}