Enable Interrupt inside another interrupt

If switch on
Enable second interrupt
Do whatever processing
Else
Disable second Interrupt
Do whatever processing
End If
Return from interrupt

short a=0;

#INT_EXT
void EXT_isr(void)
{
 if(a==1)//check if interrupt0 is enabled
 {
  output_toggle(PIN_C2);//toggle an led according to the pulses
 } 
}

#INT_EXT1
void EXT1_isr(void)
{
 a=1;
 if(a==1)
 {
  output_toggle(PIN_C1);//toggle an led whenever switch is ON
  ext_int_edge(0,L_TO_H);//interrupt0 generate at low to high transaction
  enable_interrupts(INT_EXT);
 }
}

void main()
{
 ext_int_edge(1,H_TO_L);//interrupt1 generate at high to low transaction
 enable_interrupts(INT_EXT1);//interrupt1 is enable here
 enable_interrupts(GLOBAL);
 
 while(1)
 {
  if(input(PIN_B1))//check if switch is OFF
  {
   a=0;//
   disable_interrupts(INT_EXT);//disable interrupt0
  }
  output_toggle(PIN_C0);//toggle an LED continuously
  delay_ms(500);
 }
}