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MARS Orientation

We really didn't do much with this lab. All we did was download MARS and run the sample fibonacci program he gave us.

I'll post the program below just because. Sadly, my plugin for code blocks doesn't seem to have syntax highlighting for assembly language... This will have to do.

# Compute first twelve Fibonacci numbers and put in array, then print
      .data
fibs: .word   0 : 12        # "array" of 12 words to contain fib values
size: .word  12             # size of "array" 
      .text
      la   $t0, fibs        # load address of array
      la   $t5, size        # load address of size variable
      lw   $t5, 0($t5)      # load array size
      li   $t2, 1           # 1 is first and second Fib. number
      add.d $f0, $f2, $f4
      sw   $t2, 0($t0)      # F[0] = 1
      sw   $t2, 4($t0)      # F[1] = F[0] = 1
      addi $t1, $t5, -2     # Counter for loop, will execute (size-2) times
loop: lw   $t3, 0($t0)      # Get value from array F[n] 
      lw   $t4, 4($t0)      # Get value from array F[n+1]
      add  $t2, $t3, $t4    # $t2 = F[n] + F[n+1]
      sw   $t2, 8($t0)      # Store F[n+2] = F[n] + F[n+1] in array
      addi $t0, $t0, 4      # increment address of Fib. number source
      addi $t1, $t1, -1     # decrement loop counter
      bgtz $t1, loop        # repeat if not finished yet.
      la   $a0, fibs        # first argument for print (array)
      add  $a1, $zero, $t5  # second argument for print (size)
      jal  print            # call print routine. 
      li   $v0, 10          # system call for exit
      syscall               # we are out of here.
		
#########  routine to print the numbers on one line. 

      .data
space:.asciiz  " "          # space to insert between numbers
head: .asciiz  "The Fibonacci numbers are:\n"
      .text
print:add  $t0, $zero, $a0  # starting address of array
      add  $t1, $zero, $a1  # initialize loop counter to array size
      la   $a0, head        # load address of print heading
      li   $v0, 4           # specify Print String service
      syscall               # print heading
out:  lw   $a0, 0($t0)      # load fibonacci number for syscall
      li   $v0, 1           # specify Print Integer service
      syscall               # print fibonacci number
      la   $a0, space       # load address of spacer for syscall
      li   $v0, 4           # specify Print String service
      syscall               # output string
      addi $t0, $t0, 4      # increment address
      addi $t1, $t1, -1     # decrement loop counter
      bgtz $t1, out         # repeat if not finished
      jr   $ra              # return