how to use the interrupt keyword in 8051 C code.

Hi,

There is an application note on using the interrupt vectors in C51 c programming for 8051. It goes like this-

unsigned int int_count;
unsigned char second;

void timer0 (void) interrupt 1 using 2
{ if (++int_count == 4000) { /* count to 4000 */ second++; /* second counter */ int_count = 0; /* clear interrupt counter */ }
}

Can anyone explain what does that "using 2" at the end of the function denote?

I understand that interrupt 1 specifies that this is the ISR for interrupt number for timer0 overflow at adress 000Bh. Does the last keyword "using 2" denote the polling priority of the interrupt?

TIA,
Mrunmoy