What is the longest delay you can achieve in this code?

AREA .text, CODE, READONLY delay asm PROC EXPORT delay asm LDR RO,-0x00800000 MOV R1,#1 LOOP SUBS RO, R1 BNE LOOP BX LR ENDP ALIGN END AREA .text, CODE, READONLY delay asm PROC EXPORT delay asm LDR RO,-0x00800000 MOV R1,#1 LOOP SUBS RO, R1 BNE LOOP BX LR ENDP ALIGN END