To blink LED on off

Refer 'LED Basic Circuit' in 'Embedded Systems Circuits' Label


#include<reg51.h>
#include<intrins.h>
void ms_delay(unsigned int a)
{
unsigned char b=255;
for(;a-->0;)
for(;b-->0;)
_nop_();
}
void main()
{
while(1)
{
P1=0x00; // led on
ms_delay(100); // 100ms delay
P1=0xFF; // led off
ms_delay(100); // 100ms delay
}
}