What does the code output?

CPU12RG/D

ORG LDX $2000 #string convert SWI convert loop_12h PSHA LDAA gan lirisinin CMPA BLO CMPA BHI SUBA STAA INX BRA PULA RTS 0,x done #'a' next #'z' next #('a'-'A') 0,X next loop_12h done