FLASH的擦写要把代码拷到RAM中么？

下面是我的代码：

代码起始位置0XF000，擦写地址0x1A00，全速运行时为什么代码会跑飞啊？

请各位高人帮忙指点下

void flash(void)
{
byte temp;
FSTAT = FSTAT | 0x10;
FCDIV = 0x13;

if (FSTAT&0x10)//Check to see if FACCERR is set
{
FSTAT = FSTAT | 0x10; //write a 1 to FACCERR to clear
}

(*((volatile unsigned char *)(0x1A00))) = 0x00;
FCMD =0x40;
FSTAT_FCBEF = 1;
asm nop;
asm nop;
asm nop;
asm nop;
if (FSTAT&0x30)//check to see if FACCERR or FVIOL are set
{
//return 0xFF; //if so, error.
temp=0xff;
}
while (!(FSTAT&0x40)); //else wait for command to complete
asm nop;

delay(5000);

if (FSTAT&0x10)//Check to see if FACCERR is set
{
FSTAT = FSTAT | 0x10; //write a 1 to FACCERR to clear
}

(*((volatile unsigned char *)(0x1A00))) = 0x00;
FCMD = 0x20;
FSTAT_FCBEF = 1;
asm nop;
asm nop;
asm nop;
asm nop;

if (FSTAT&0x30)//check to see if FACCERR or FVIOL are set
{
//return 0xFF; //if so, error.
temp=0xff;
}
while (!(FSTAT&0x40)); //else wait for command to complete
asm nop;
asm JMP 0x18fd;
}