main:
la $a0, prompt
.data
prompt: .asciiz "Number to compute fib of:"
.text
li $v0, 51
syscall
addiu $sp, $sp, -4
sw $a0, 0($sp)
jal fib
lw $a0, 0($sp)
sw $v0, 0($sp)
la $a1, output2
jal int2str
la $a0, output1
.data
output1: .ascii "The value of fib("
output2: .space 12
output3: .asciiz ") is "
.text
lw $a1, 0($sp)
li $v0, 56
syscall
addiu $sp, $sp, 4
li $v0, 10
syscall


fib:
addiu $sp, $sp, -8
sw $ra, 0($sp)
sw $a0, 4($sp)
slti $t0, $a0, 2
bne $t0, $zero, baseCase  
addi $a0, $a0, -1
jal fib
lw $a0, 4($sp)
sw $v0, 4($sp)
addi $a0, $a0, -2
jal fib
lw $t0, 4($sp)
add $v0, $v0, $t0
j return


baseCase:
li $v0, 1

return:
lw $ra, 0($sp)
addiu $sp, $sp, 8
jr $ra

int2str:
# takes as arguments
#   $a0 an integer to convert
#   $a1 the memory address for the result
# and converts the integer to a string
move $t1, $a1   # $t1 is the left-hand finger

main_int2str_loop:
rem $t0, $a0, 10
addi $t0, $t0, 48
sb $t0, 0($a1)
addiu $a1, $a1, 1
div $a0, $a0, 10
bne $a0, $zero, main_int2str_loop 
sb $0, 0($a1)
addiu $a1, $a1, -1  # $a1 is the right-hand finger

int2str_reverse_loop:
sltu $t2, $t1, $a1  # a value of 1 means we should keep going
beq $t2, $zero, int2str_done
# we know the left finger is still to the left of the right finger
lb $t2, 0($t1)  # $t2 was the byte on the left
lb $t3, 0($a1)  # and $t3 was on the right
sb $t2, 0($a1)
sb $t3, 0($t1)  # now they are swapped
addiu $a1, $a1, -1
addiu $t1, $t1, 1
j int2str_reverse_loop

int2str_done:
jr $ra

strcat:
# takes as arguments ... and concatenates the strings
la $t0, output1
la $t1, output3
.data
output4: .space 12
.text
la $t2, output4
lb $t3, 0($t0)
sb $t3, 0($t2)
addiu $t0, $t0, 1
addiu $t2, $t2, 1