LDA myValue
CMP #3
BEQ .doTheThing

;if not equal, check myOtherValue

LDA myOtherValue
CMP #5
BNE .skip

;if we got to here, either "myValue == 3" or "myOtherValue" == 5 evaluated to true.

.doTheThing:
STA myResult         ;any nonzero value is considered TRUE, so we've stored 5 into myResult.

.skip: