简单选择排序：
第i次扫描，在r[i]到r[n]中挑选最小的，放在r[i]
.data
array: .word 13,27,38,97,76,65,49
.text
la $a0,array
li $t0,6
lp0:
addi $a1,$a0,4
addi $t1,$t0,-1#counter
lp1:
lw $t2,($a0)#取出本次循环比较的单元
lw $t3,($a1)
ble $t2,$t3,next
sw $t2,($a1)
sw $t3,($a0)#交换位置
next:
addi $a1,$a1,4
addi $t1,$t1,-1
bgt $t1,$0,lp1
addi $t0,$t0,-1
bgt $t0,$0,lp0
li $v0,10
syscall
