day2 arm

作业1

 

.text
.global _start

_start:
	mov r0,#9
	mov r1,#15
Loop:
	cmp r0,r1
	beq stop
	subhi r0,r1
	subcc r1,r0
	b Loop
stop:
	b stop
.end

 作业2

用汇编for循环实现1~100之间的和

.text
.global _start

_start:
	mov r0,#1 @int i=1
	mov r1,#0 @int sum=0
	bl sum

stop:
	b stop

sum:
	cmp r0,#100 @i<=100
	add r1,r0	@sum+=i
	add r0,#1	@i++
	moveq pc,lr 
	b sum
.end

作业3

.text
.global _start

_start:
	ldr r0,=0x40000800
	ldr r1,=0x11111111
	ldr r2,=0x22222222
	ldr r3,=0x33333333
	@ [0x40000804]=0x11111111 r0=0x40000800
	str r1,[r0,#4]
    @ [0x40000800]=0x22222222 r0=0x40000804
	str r2,[r0],#4
    @ [0x40000808]=0x33333333 r0=0x40000808
	str r3,[r0,#4]!
	
.end