keil编译报错error C202: undefined identifier

keil编译报错error C202: undefined identifier,网上找来的代码，我不懂修改，望大佬帮帮我吧
#include <AT89X51.h>
static unsigned int count; //计数
static int step_index; //步进索引数,值为0-7
static bit turn; //步进电机转动方向
static bit stop_flag; //步进电机停止标志
static int speedleve1; //步进电机转速参数,数值越大速度越慢,最小值为1,速度最快
static int spcount; //步进电机转速参数计数
void delay(unsigned int endcount); //延时函数,延时为 endcount*0.5毫秒
void gorun();       //步进电机控制步进函数
void main(void)
{
count = 0;
step_index = 0;
spcount = 0;
stop_flag = 0;
P1_0 = 0;
P1_1 = 0;
P1_2 = 0;
P1_3 = 0;
EA = 1;          //允许CPU中断
TMOD = 0x11; //设定时器0和1为16位模式1
ET0 = 1;          //定时器0中断允许
TH0 = 0xFE;
TL0 = 0x0C; //设定时每隔0.5ms中断一次
TR0 = 1;       //开始计数
turn = 0;
speedlevel = 2;
delay(10000);
speedlevel = 1;
do{
      speedlevel = 2;
      delay(10000);
      speedlevel = 1;
      delay(10000);
      stop_flag=1;
      delay(10000);
      stop_flag=0;
}while(1);
}

//定时器0中断处理

void timeint(void) interrupt 1
{
TH0=0xFE;
TL0=0x0C; //设定时每隔0.5ms中断一次
count++;
spcount–;
if(spcount<=0)
{
   spcount = speedlevel;
   gorun();
}
}
void delay(unsigned int endcount)
{
count=0;
do{}while(count<endcount);

}

void gorun()

{ if (stop_flag==1)
{
   P1_0 = 0;
   P1_1 = 0;
   P1_2 = 0;
   P1_3 = 0;
   return;
}
switch(step_index)
{
case 0: //0
P1_0 = 1;
P1_1 = 0;
P1_2 = 0;
P1_3 = 0;
break;
case 1: //0、1
P1_0 = 1;
P1_1 = 1;
P1_2 = 0;
P1_3 = 0;
break;
case 2: //1
P1_0 = 0;
P1_1 = 1;
P1_2 = 0;
P1_3 = 0;
break;
case 3: //1、2
P1_0 = 0;
P1_1 = 1;
P1_2 = 1;
P1_3 = 0;
break;
case 4:  //2
P1_0 = 0;
P1_1 = 0;
P1_2 = 1;
P1_3 = 0;
break;
case 5: //2、3
P1_0 = 0;
P1_1 = 0;
P1_2 = 1;
P1_3 = 1;
break;
case 6: //3
P1_0 = 0;
P1_1 = 0;
P1_2 = 0;
P1_3 = 1;
break;
case 7: //3、0
P1_0 = 1;
P1_1 = 0;
P1_2 = 0;
P1_3 = 1;
}
if (turn==0)
{
step_index++;
if (step_index>7)
   step_index=0;
}
else
{
step_index–;
if (step_index<0)
   step_index=7;
}
  }