bigint在二进制（8）列中的二进制表示(Binary representation of bigint into a binary(8) column)

minutes:
    bgt $t1,59,hour     ; 1
seconds:
    bgt $t2,59,minutes  ; 2
    li  $v0, 1          ; 3
    :
    addi $t2,$t2,1
    j seconds
 
 当$t2最终达到60 ，你所拥有的代码段将是一个无限循环。 
 
 在代码中没有任何地方你实际上将$t2(secs)设置回零并增加$t1(mins)所以，一旦$t2达到60并且你跳到seconds ，这里是执行路径： 2, 1, 2, 1, 2, ... ，没有机会再次升级到3 。 
 
 至于如何修复它，不要只是在$t2溢出时跳回到minutes ，你必须将$t2设置回零并增加$t1 。 然后你需要检查$t1溢出等等。 
 
 因为它可能是classwork，我只提供伪代码（汇编程序），但是构造代码的最佳方法可能是： 
 
start:
    $t0 = 0
    $t1 = 0
    $t2 = -1

loop:
    $t2 = $t2 + 1
    if $t2 < 60 goto skipmin
    $t2 = 0                   ; special when secs -> 60
    $t1 = $t1 + 1

skipmin:
    if $t1 < 60 goto skiphour
    $t1 = 0                   ; special when mins -> 60
    $t0 = $t0 + 1
    if $t0 == 24 goto end     ; stop at 24:00:00

skiphour:
    display $t0:$t1:$t2
    goto loop

end:
    stop program
 
 
 至于如何使用前导零显示值，再次使用伪代码（仅对于秒值，您将必须将其展开以处理分钟和小时）： 
 
    if $t2 > 9 goto nozerosec
    syscall 4 with $a0 pointing at "0"
nozerosec:
    syscall 1 with $a0 loaded from $t2
 
 这只是通过检查您要输出的值来工作，如果它小于10，则首先输出前导零。 
 
 这假设（似乎是）syscall 1用于输出$a0的值，而syscall 4用于输出$a0指向的字符串。 
 
 而且，对于额外的积分，您可以使填充输出成为一个单独的函数来调用，而不是在主程序中重复自己。 

minutes:
    bgt $t1,59,hour     ; 1
seconds:
    bgt $t2,59,minutes  ; 2
    li  $v0, 1          ; 3
    :
    addi $t2,$t2,1
    j seconds
 
When $t2 eventually gets to 60, that code segment you have there is going to be an infinite loop.
 
Nowhere in the code are you actually setting $t2(secs) back to zero and incrementing $t1(mins) so, once $t2 hits 60 and you jump to seconds, here's the execution path: 2, 1, 2, 1, 2, ..., with no chance of advancing to 3 again.
 
As to how to fix it, don't just jump back to minutes when $t2 overflows, you have to set $t2 back to zero and increment $t1. Then you need to check $t1 for overflow and so on.
 
Since it's probably classwork, I'll offer pseudo-code (of an assembler variety) only, but possibly the best way to structure your code would be:
 
start:
    $t0 = 0
    $t1 = 0
    $t2 = -1

loop:
    $t2 = $t2 + 1
    if $t2 < 60 goto skipmin
    $t2 = 0                   ; special when secs -> 60
    $t1 = $t1 + 1

skipmin:
    if $t1 < 60 goto skiphour
    $t1 = 0                   ; special when mins -> 60
    $t0 = $t0 + 1
    if $t0 == 24 goto end     ; stop at 24:00:00

skiphour:
    display $t0:$t1:$t2
    goto loop

end:
    stop program
 
 
As to how to display values with leading zeroes, again with pseudo-code (for just the seconds value, you'll have to expand it to handle minutes and hours):
 
    if $t2 > 9 goto nozerosec
    syscall 4 with $a0 pointing at "0"
nozerosec:
    syscall 1 with $a0 loaded from $t2
 
This simply works by checking the value you're going to output and, if it's less than 10, outputting a leading zero first.
 
This is assuming (as it seems to be) that syscall 1 is for outputting a value in $a0 and syscall 4 is for outputting a string pointed to by $a0.
 
And, for extra credits, you can make the padded output a separate function to be called rather than repeating yourself in the main program.