下面的代码包含一个异常处理程序，它处理syscall#12错误输入的异常，然后将0xc更改为0xd;前进异常pc（epc）并恢复用户代码：

.macro print_char
    li $v0, 11
    lbu $a0, ($s0)
    syscall
.end_macro
 
.macro read_char
    li $v0, 12
    syscall
    sb $v0, ($s0)
.end_macro
 
.text
    # Initialize registers.
    li $s0, 0x10010000
    li $t0, 0x0
 
    read_char
    print_char
    
    li $v0, 10
    syscall             # terminate program
    

.ktext 0x80000180       # install this next code as kernel exception handler
    li $v0, 0xd         # change 0xc in $v0 to 0xd
    mfc0 $k1, $14       # fetch epc (address of the offending syscall)
    addi $k1, $k1, 4    # advance to next instruction
    mtc0 $k1, $14       # update epc
    eret                # resume user code

请注意，这个处理程序绝对没有错误检查-特别是，它假设调用它的唯一原因是处理syscall#12错误。