C51编译出错，请高手帮我看看

*** WARNING L16: UNCALLED SEGMENT, IGNORED FOR OVERLAY PROCESS
    SEGMENT: ?PR?CROL?TEXT1
*** WARNING L1: UNRESOLVED EXTERNAL SYMBOL
    SYMBOL:  MAIN
    MODULE:  D:\PROGRAM FILES (X86)\KIEL\C51\LIB\C51S.LIB (?C_INIT)
*** WARNING L2: REFERENCE MADE TO UNRESOLVED EXTERNAL
    SYMBOL:  MAIN
    MODULE:  D:\PROGRAM FILES (X86)\KIEL\C51\LIB\C51S.LIB (?C_INIT)
    ADDRESS: 0010H
Program Size: data=11.0 xdata=0 code=206
creating hex file from "1"...
"1" - 0 Error(s), 3 Warning(s).
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#include <reg52.h>
#include <intrins.h>
#define uchar unsigned char
#define uint unsigned int
void delay(uint);
void crol()
{
uchar a;
uchar b;
a=0xFE;
        while(1)
        {
        P0=a;
        delay(10);
        b=_crol_(a,1);
        }
}
void delay(uint z)
{
uint x;
uint y;
        for(x=100;x>0;x--)
                for(y=z;y>0;y--);
}

没没没没没没错啊，0 error，

3 warings ，不能 debug

解决了 ，没有MAIN 函数