; ; 求 19! ; AREA jcCode, CODE, READONLY ENTRY start mov r0, #1 ;结果低32位 mov r1, #0 ;结果高32 mov r2, #19 ;循环计数器 jcloop umull r0, r3, r2, r0; [r3 r0] <- r0 * r2 mla r1, r2, r1, r3; r1 <- r1 * r2 + r3 subs r2, r2, #1 bne jcloop stop mov r0, #0x18 ldr r1, =0x20026 swi 0x123456 end
