Exception encountered when trying to display the length of a string given by a user. MIPS -

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i trying compute length of string given user. every time try run code, message "exception occurred @ pc=(a address) followed message :"bad address in data/stack read: (another address). know has stack can't figure out problem. code in mips bello , using qtspim. appreciated.

sentence:   .space 6 prompt: .asciiz "enter sentence. max 6 characters, plus terminator  .\n"            .text       # start of code section main:               # prompt displayed.      li $v0, 4        # system call code printing string = 4     la $a0, prompt  # load address of string printed $a0     syscall         # call operating system perform operation;                     # $v0 specifies system function called;                     # syscall takes $v0 (and opt arguments)  ##read string, plus terminator, sentence     la      $t0,    sentence     li      $t0,    6     li      $v0,    8      add $v0, $zero, $zero   #initialize length 0 loop:     lbu $s0, 0($t0)      #load 1 character of string     addi $t0,$t0,1          #point next character     addi $v0,$v0,1          #increment length 1     bne $s0,$zero, loop     #repeat if not null yet end_loop:     addi $v0, $v0, -1       #don't count null terminator      li $v0, 4               #display actual length     syscall  exit: #exit program      li $v0, 10     syscall 

##read string, plus terminator, sentence     la      $t0,    sentence     li      $t0,    6

here you're loading address of sentence $t0, , overwrite $t0 value 6. root cause of exception, since following lbu attempt read address 0x00000006. suggest remove li.

   li      $v0,    8      add $v0, $zero, $zero   #initialize length 0

this li pointless since you're setting $v0 0 on next line, li can removed.

sentence:           .space 6 prompt:     .asciiz "enter sentence. max 6 characters, plus terminator  .\n"

you user allowed enter 6 characters. allocate space 6 bytes, meaning null terminator wouldn't fit if user enters 6 characters.


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