I think you can clear the I0/I1 bit of SR with the following code:
asm(bfclr #$0300, SR); //enable interrupt
you can set the I0/I1 bit in SR with the following code
asm(bfset #$0300, SR); //disable interrupt
if you want to jump based on the condition of SR, you can use the code Jcc or Bcc instruction.
BR
xiangjun Rong