Creating (and accessing) an array in MIPS

Question

I'm trying to create an array in MIPS Assembly, and then add all the elements together. However, when I try to assemble the following, it says

Error in read_array line 1 position 7: ".word" directive cannot appear in text segment Assemble: operation completed with errors.

Here's my assembly:

list: .word 3, 2, 1, 0, 1, 2
li $t0, 0x00000000  #initialize a loop counter to $t0
li $t4, 0x00000005  #last index of array
li $t3, 0x00000000  #this will hold our final sum
la $t1, list  #the address of list[0] is in $t1

loop: addi $t0, $t0, 0x00000001 #index++
  add $t5, $t0, $t0 #array index X2
  add $t5, $t0, $t0 #array index X2 again
  add $t6, $t5, $t1 #4x array index in $t6

  lw $t2, 0($t6)   #load list[index] into $t2
  add $t3, $t3, $t2 #$t3 = $t3 + $t2
  beq $t0, $t4, end
  j loop

end:

Thanks!

I am aware of some logical errors in this code, but I got my question answered. Thanks! — hodgesmr
– hodgesmr, Commented Mar 3, 2010 at 3:47
That's really weird, IDK if this limitation is intentional to protect beginners from mixing data with code and having their program crash when execution falls into their data, or what. In most assemblers, you can use .byte / .word or db / dd anywhere to emit whatever bytes you want at any position. (e.g. to emit a non-default encoding of an instruction for some reason.) — Peter Cordes
– Peter Cordes, Commented Dec 5, 2017 at 4:01

Carl Norum · Accepted Answer · 2019-09-09 18:36:09Z

16

You have to put this line:

list: .word 3, 2, 1, 0, 1, 2

Into the .data section. Check this quick tutorial.

edited Sep 9, 2019 at 18:36

answered Mar 3, 2010 at 3:33

Carl Norum

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1 Comment

user7075574 Over a year ago

The 'quick tutorial' link is off.

John Knoeller · Accepted Answer · 2010-03-03 03:49:51Z

6

The error is telling you you can't put data (.word 3, 2) in the code segment. "Text segment" is an old style term meaning "code segment" http://en.wikipedia.org/wiki/Code_segment

The assembler wants you to declare a data segment and put the array there. I've never done Mips assembler, but I would expect it to be something like this

.data
list: .word 3, 2, 1, 0, 1, 2

.text
start:
li $t0, 0x00000000  #initialize a loop counter to $t0
li $t4, 0x00000005  #last index of array
li $t3, 0x00000000  #this will hold our final sum
la $t1, list  #the address o

edited Mar 3, 2010 at 3:49

answered Mar 3, 2010 at 3:38

John Knoeller

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2 Comments

Carl Norum Over a year ago

It would be .text rather than .code in most assemblers I've used.

John Knoeller Over a year ago

@Carl: you're probably right, especially given the error message. I'll change it.

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