Implementation of watches in MIPS

Question

Hi to all users of Stackoverflow, I am trying to write code in MIPS that will implement the clock. I create my own exception handler and I am doing something wrong, because currently I only show 00:00. Therefore, I use a flag to decide if this is a time interrupt, but this flag is never set to one, and I don’t understand why not. If someone can see my mistake or a huge misunderstanding of the concept on my part, please tell us.

This is my code:

.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