Write a subroutine to clear the flag register and accumulator?

MVI A,0

ADI 1

MVI A,0

The first MVI only clears the accumulator. The ADI adds one to it, clearing the N, Z, O, C, and P flags. The second MVI clears the accumulator again.

It is possible that I have the sense of the P flag backwards. If so, replace the first MVI with MVI A,2 and the P flag will be correct.