In RPG or RPGLE but not RPGLE-free you could use the MOVEA (move array command)
MOVEA ’0000′ *in80
would move *zeros to *in80, *in81, *in82, *in83
But I find it’s better to do it in 4 discreate commands perhaps in a Subroutine.
Maintenance programmers might not catch the meaning as quickly as the four statements.
In RPGLE-Free you can use it to turn off indicators 80 to 83.
%SubArr(*IN : 80 : 4) = *Off