what does this code do?

HI, i'm a little confused, what exactly does this code do?
I know it tests bit zero of the status flag right? what is the implication of that on a system?


MOV A, STATUS
JNB ACC.0, NO_PWR

Hi, moves the value of the status register in to the accumulator and checks for the Parity bit, if it is low, it transfers execution to the subroutine NO_PWR.