Converting numerical input to corresponding string using MIPS

[JAO012]

I am writing a MIPS SPIM program that will take integer input, and output the corresponding words. For example, if 123 is input, then one two three will be output.

I can input an integer but I get zero repeating infinite times as the output every time. Any help is appreciated.

My source code is below:


.data
prompt: .asciiz "Please input a positive integer "
echo: .asciiz "\nYou have input "
echo1: .asciiz "\nThis is an acceptable value. The output is "
echo2: .asciiz "\nThis is not an acceptable value. Please try again. "
zero0: .asciiz "zero "
one1: .asciiz "one "
two2: .asciiz "two "
three3: .asciiz "three "
four4: .asciiz "four "
five5: .asciiz "five "
six6: .asciiz "six "
seven7: .asciiz "seven "
eight8: .asciiz "eight "
nine9: .asciiz "nine "
buffer: .space 100

.text
main:

li $v0,4 #print string
la $a0, prompt
syscall

li $v0, 5 #reads in integer
syscall

li $v0, 4 #print string
la $a0, echo
syscall

#li $v0, 1
#syscall

move $v0, $t1 #moves integer into $t1

j checkin

loop1:
beq $t1,0,next #when there are no more values, stop pushing
sub $sp, $sp, 4 #subtract 4 bytes off stack
sw $s0,0($sp) #store values in $s0
j next

next:
bge $t1,0,convert #go through and remove values from stack
lw $v0, 4($sp) #load into v0
add $sp, $sp, 4 #add bytes back to stack
jr $ra #jump register

##check if the input is positive
checkin:
bgez $t1, yes
blez $t1, no
j loop1

convert: #changes value of each integer to respective word value, and stores the result #on the stack
beq $t1,0,zero
beq $t1,1,one
beq $t1,2,two
beq $t1,3,three
beq $t1,4,four
beq $t1,5,five
beq $t1,6,six
beq $t1,7,seven
beq $t1,8,eight
beq $t1,9,nine

j onestring

# each loop takes the value off the stack and then prints the string value corresponding to #each integer

zero:
sub $sp, $sp, 4
sw $t3, 0($sp)

li $v0, 4
la $a0, zero0
syscall


j convert

one:
sub $sp, $sp, 4
sw $t3, 0($sp)

li $v0, 4
la $a0, one1
syscall
j convert

two:
sub $sp, $sp, 4
sw $t3, 0($sp)

li $v0, 4
la $a0, two2
syscall

j convert

three:
sub $sp, $sp, 4
sw $t3, 0($sp)

li $v0, 4
la $a0, three3
syscall

j convert

four:
sub $sp, $sp, 4
sw $t3, 0($sp)

li $v0,4
la $a0, four4
syscall

j convert

five:
sub $sp, $sp, 4
sw $t3, 0($sp)

li $v0,4
la $a0, five5
syscall

j convert

six:
sub $sp, $sp, 4
sw $t3, 0($sp)

li $v0,4
la $a0, six6
syscall

j convert

seven:
sub $sp, $sp, 4
sw $t3, 0($sp)

li $v0,4
la $a0, seven7
syscall

j convert

eight:
sub $sp, $sp, 4
sw $t3, 0($sp)

li $v0,4
la $a0, eight8
syscall

j convert

nine:
sub $sp, $sp, 4
sw $t3, 0($sp)

li $v0,4
la $a0, nine9
syscall

j convert

onestring: #combines all string values of integers into one string
la $t3, buffer
li $a1, 100 #100 max chars
beqz, $t3, end
lw $t3, 4($sp)
add $sp, $sp, 4

j end

yes: #acceptable input
li $v0, 4
la $a0, echo1
syscall

j convert

end:
li $v0, 4 #print full string
la $a0, buffer
syscall

li $v0, 10
syscall

no:
li $v0,4 #not acceptable input
la $a0, echo2
syscall

li $v0,10
syscall

 

[Mark44]

Your SPIM environment includes a debugger, I'm pretty sure. Use it to single step through your program. You need to check two things:
1) why zero is being displayed every time.
2) why you're getting an infinite loop instead of a loop that runs as many times as the number of digits in your input.