Question

这是我的代码：

.data
test1:
    .word   9
    .word   8
    .word   7
    .word   6
    .word   5
    .word   4
    .word   3

size:   .word   7

#$t0 stores i
#$t1 stores j
#$t2 stores address of array[j]
#$t3 stores address of array[j + 1]
#$t4 stores value of array[j]
#$t5 stores value of array[j + 1]
#$t6 stores 0 if array[j] >= array[j + 1], 1 otherwise

.text
bubblesort:
    addi $t0, $zero, -1     #int i = -1;
    addi $t9, $zero, 7
    la $a0, test1               #$a0 = base address of array
Loop1:
    addi $t9, $t9, -1           #$t9 = n - 1
    addi $t0, $t0, 1            #i=0
    beq $t0, $t9, print         #i < n - 1
    addi $t1, $zero, 0          #int j = 0;
    j Loop2
Loop2:
    sub $t8, $t9, $t0           #$t8 = n - i
    beq $t1, $t8, Loop1         #j < n - i - 1
    sll $t2, $t1, 2             #$t2 = j * 4
    add $t2, $t2, $a0           #t2 = $t2 + baseAddress
    lw $t4, 0($t2)              #$t4 = arr[j]
    addi $t3, $t2, 4        #$t3 = $t2 + 4
    lw $t5, 0($t3)          #$t5 = arr[j + 1]
    slt $t6, $t4, $t5       #$t6 = arr[j] < arr[j + 1]
    bne $t6, $zero, Back2       #if($t6 == 1) jump to Back2
    sw $t5, 0($t2)          #arr[j] = arr[j + 1]
    sw $t4, 0($t3)          #arr[j + 1] = arr[j]
    j Back2                 #Jump to Back2
Back2:
    addi $t1, $t1, 1        #j++
    j Loop2             #Jump to top of Loop2
exit:
    addi $v0, $zero, 10
    syscall
print:
    lw $t3, size
    la $t1, test1
    li $t2, 0
    jal print_loop

print_loop:
    beq $t2, $t3, exit
    lw $a0, 0($t1)
    li $v0, 1
    syscall
    addi $t2, $t2, 1
    addi $t1, $t1, 4
    j print_loop

它输出以下内容： 6574839 它应该输出3456789，我相信它在这里无法正常工作

sw $t5, 0($t2)          #arr[j] = arr[j + 1]
sw $t4, 0($t3)          #arr[j + 1] = arr[j]

但是我不确定为什么它不能正确存储值。仅应使用指令add，addi，addiu，addu和andi，la，lui，lw，nor，xor，xori或ori，slt，slti，sltiu，sltu，sll，srl，sra， sllv，srlv，srav，sw， sub，subu，beq，bne，j，jal，jr。

Answer 1

请记住，一个整数需要4个字节，而不仅仅是一个字节。数组的大小是7 * 4个字节。

    .data
    test1:
    .word   9
    .word   8
    .word   7
    .word   6
    .word   5
    .word   4
    .word   3

    size:   .word   7

    #$t0 stores i
    #$t1 stores j
    #$t2 stores address of array[j]
    #$t3 stores address of array[j + 1]
    #$t4 stores value of array[j]
    #$t5 stores value of array[j + 1]
    #$t6 stores 0 if array[j] >= array[j + 1], 1 otherwise

    .text
    bubblesort:
    #addi $t0, $zero, -1     #int i = -1;
    addi $t0,$t0,-4           # int takes 4 bytes (no 1 byte)
    #addi $t9, $zero, 7
    li $t9,28                 # size of array = 7*4 bytes 
    la $a0, test1               #$a0 = base address of array
    Loop1:

    #addi $t9, $t9, -1           #$t9 = n - 1
    addi $t9,$t9,-4              # $t9=n-1 
    addi $t0, $t0, 4            #i=0
    blt $t0, $t9, print         #i < n - 1
    addi $t1, $zero, 0          #int j = 0;
    j Loop2
    Loop2:
    sub $t8, $t9, $t0           #$t8 = n - i
    blt $t1, $t8, Loop1         #j < n - i - 1
    sll $t2, $t1, 2             #$t2 = j * 4
    add $t2, $t2, $a0           #t2 = $t2 + baseAddress
    lw $t4, 0($t2)              #$t4 = arr[j]
    addi $t3, $t2, 4        #$t3 = $t2 + 4
    lw $t5, 0($t3)          #$t5 = arr[j + 1]
    slt $t6, $t4, $t5       #$t6 = arr[j] < arr[j + 1]
    bne $t6, $zero, Back2       #if($t6 == 1) jump to Back2
    sw $t5, 0($t2)          #arr[j] = arr[j + 1]
    sw $t4, 0($t3)          #arr[j + 1] = arr[j]
    j Back2                 #Jump to Back2
    Back2:
    addi $t1, $t1, 4        #j++
    j Loop2             #Jump to top of Loop2
    exit:
    addi $v0, $zero, 10
    syscall
    print:
    lw $t3, size
    la $t1, test1
    li $t2, 0
    jal print_loop

    print_loop:
    beq $t2, $t3, exit
    lw $a0, 0($t1)
    li $v0, 1
    syscall
    addi $t2, $t2, 1
    addi $t1, $t1, 4
    j print_loop

为什么我的MIPS气泡排序代码不起作用？

1 个答案: