MIPS中的时钟实现

Question

嗨，对所有Stackoverflow用户， 我正在尝试用MIPS编写一个实现时钟的代码。我正在构建自己的异常处理程序，我做错了，因为目前我只显示00:00。所以我使用一个标志来判断它是否是一个时间中断但是该标志永远不会设置为一个，我不明白为什么不。如果有人能够看到我的错误或对我这个概念的巨大误解，请告诉我。

这是我的代码：

    .globl __eoth
__eoth:
    .globl Yesdisplay    #flag to indicate if a second passed

Yesdisplay:  .word 0
.data

next:
    .asciiz "\n"

    .text
    .globl __start
__start:
    li   $t2, 0
    li   $s8, 1
    li   $s7, 1
    li   $s6, 0
    li   $s4, 0
    li   $s5, 4
    li   $t5, 0
    li   $t6, 10
    li   $t7, 1
    li   $v0, 4
    li   $s3, 8
#################################################################
#Set my coprocessor register $11 to 100 so it will give a second#
#################################################################
    li   $s6, 100
    mtc0 $s6, $11
    #li   $s4, 0
#################################################################
#Set bit 0 in registry $12 to 1                                 #
#################################################################
    mfc0 $t9, $12
    ori  $t9, $t9, 0x08801
    mtc0 $t9, $12
#################################################################
#Set bit 1 in keyboard control register at 0xffff 0000 to 1     #
#################################################################
    #lw   $t0, 0xffff0000                                           
    #ori  $t0, $t0, 0x02                                              
    #sw   $t0, 0xffff0000      

    li $t5, 48
    sw   $t5, 0xffff000c


poll4:
    lw   $t1, 0xffff0008
    andi $t1, $t1, 0x0001
    bne  $t1, $t7, poll4
    li   $t5, 48
    sw   $t5, 0xffff000c

poll5:
    lw   $t1, 0xffff0008
    andi $t1, $t1, 0x0001
    bne  $t1, $t7, poll5
    li   $t5, 58
    sw   $t5, 0xffff000c

poll6:
    lw   $t1, 0xffff0008
    andi $t1, $t1, 0x0001
    bne  $t1, $t7, poll6
    li   $t5, 48
    sw   $t5, 0xffff000c

poll7:
    lw   $t1, 0xffff0008
    andi $t1, $t1, 0x0001
    bne  $t1, $t7, poll7
    li   $t5, 48
    sw   $t5, 0xffff000c

poll1:

intial_ended:

timer_inter:        
    addi $t5, $t5, 1                    #num
    addi $t7, $t5, 48
poll2:
    lw   $t1, 0xffff0008
    andi $t1, $t1, 0x00001
    bne  $t1, $s7, poll2
    sw   $s3, 0xffff000c  #backspace-1
poll3:
    lw   $t1, 0xffff0008
    andi $t1, $t1, 0x00001
    bne  $t1, $s7, poll3
    lw   $t1, Yesdisplay
    bne  $t1, $t2, poll3
    sw   $t7, 0xffff000c#$t7, 0xffff000c  #printing the first digit

    beq  $t5, $t6, tens_of_a_second 

    j timer_inter

tens_of_a_second:

poll9:
    lw   $t1, 0xffff0008
    andi $t1, $t1, 0x00001
    bne  $t1, $s7, poll9
    sw   $s3, 0xffff000c  #backspace-1

poll11:
    lw   $t1, 0xffff0008
    andi $t1, $t1, 0x00001
    bne  $t1, $s7, poll11
    sw   $s3, 0xffff000c  #backspace-1
    addi $t7, $s8, 48

poll10:
    lw   $t1, 0xffff0008
    andi $t1, $t1, 0x00001
    bne  $t1, $s7, poll10
    addi $t7, $s8, 48
    sw   $t7, 0xffff000c  #print the tens of a second 
    addi $s8, $s8, 1
    li   $t5, 0

    beq  $t5, $t6, minuts   

    j timer_inter

minuts:
poll12:
    lw   $t1, 0xffff0008
    andi $t1, $t1, 0x00001
    bne  $t1, $s7, poll12
    sw   $s3, 0xffff000c  #backspace-1


quite:
    li   $v0, 10
    syscall

    .kdata
s1: .word 0
s2: .word 0
s3: .word 0

    .ktext 0x80000180
    .set noat
    move $k1 $at
    .set at
    sw   $a0, s1
    sw   $v0, s2 
    sw   $t1, s3
    mfc0 $k0, $13
    srl  $a0, $k0, 2
    andi $a0, $a0, 0x01f
    bne  $a0, $zero, inter_eret
    lw   $a0, s1
    lw   $v0, s2 
    eret

inter_eret:
    andi $k1, $k0, 0x8000
    bne  $k1, $zero, timer_inter_eret
    lw   $a0, s1
    lw   $v0, s2 
    eret

timer_inter_eret:
    .set noat
    move $k1, $at
    .set at
    mtc0 $zero, $9
    eret



    addi $t1, $zero, 1
    sw   $t1, Yesdisplay 
    lw   $a0, s1
    lw   $v0, s2 
    lw   $t1, s3
    .set noat
    move $k1, $at
    .set at
    mtc0 $zero, $9
    eret