Printing out integer in MIPS

f15e

I don't want to hard code an integer to be printed out such as:

li $v0, 1 # system call code for print_int
la $a0, 5 # address of int to print
syscall # print integer

which prints out integer 5.

What I need to do is the following:

li $v0, 1 # system call code for print_int
la $a0, INT # address of int to print; this line goes to INT: where
# $s0 = 0 + 5 and returns to go to syscall to print integer
syscall # print integer

where the code below is located somewhere else in the code.
INT: add $s0, $zero, $t0 # where $t0 has 5 stored in it

I get errors when I run this code. I would really appreciate help with this.

THANKS!!!

Linc

(bump back onto hot threads for a new member)

Sorry mate, doesn't look like our knowledge base covers this...

Shorty

If you can wait till Monday, I know someone at work who should be able to answer that question

shwaip

I think your problem is that your code:
la $a0, INT
...
INT: add $s0, $0, $t0

is loading the address of the add instruction, not the result of the add instruction.

could you post the entirety of your code...I think I may know what's going on, but I'm not sure.

f15e

Thanks for the reply shwaip!!

You are correct. My problem is with the code la $a0, INT. It doesn't like the INT; it only works if I hard code it: la $a0, 3.

I am looking for a way to print 3 without having to hard code it.
I am guessing the la doesn't work unless I hardcode the 3. I don't know. Any suggestions?

shwaip

are you trying to jump to a procedure later in the code? It would really help if you could attach the assembly file.

f15e

The code is not complete. What I want to do is at the beginning of main, jump to Constructor1 to set $s0 to 3 and then go to itsAge to set $s1 to $s0. This is sort of like a class in C++. Like I said before, I don't have Constructor1: or itsAge: in the code right now. Anyway, here is the code:


.data

#*********************************************************
# Class Cat
#*********************************************************

# Constructor of Cat
# void Cat::Cat(int initialAge)
Constructor1: addi $s0, $zero, 3

# GetAge, returns value of itsAge member
itsAge: add $s1, $zero, $s0

# void Cat::Meow()
Meow: .asciiz "Meow."

#End of Class Cat

#*********************************************************

#*********************************************************
Cookie1: .asciiz "Cookie is a cat who is "
Cookie2: .asciiz "Now Cookie is "
Purry1: .asciiz "Purry is a cat who is "
Purry2: .asciiz "Now Purry is "
YearsOld: .asciiz " years old."
NewLine: .asciiz "\n"
#*********************************************************

.text
.globl main


main: # Start of Main() program


li $v0, 4 # system call code for print_str
la $a0, Meow # address of string to print "Meow."
syscall # print the string

li $v0, 4 # system call code for print_str
la $a0, NewLine # address of string to print "\n"
syscall # print the string


li $v0, 4 # system call code for print_str
la $a0, Cookie1 # address of string to print "Cookie is a
# cat who is "
syscall # print the string



li $v0, 1 # system call code for print_int
la $a0, 3 # address of int to print 3 Cookies age
syscall # print the integer

li $v0, 4 # system call code for print_str
la $a0, YearsOld # address of string to print "years old."
syscall # print the string


li $v0, 4 # system call code for print_str
la $a0, NewLine # address of string to print "\n" New line.
syscall # print the string

li $v0, 4 # system call code for print_str
la $a0, Meow # address of string to print "Meow."
syscall # print the string


li $v0, 4 # system call code for print_str
la $a0, NewLine # address of string to print "\n" New line.
syscall # print the string

li $v0, 4 # system call code for print_str
la $a0, Cookie2 # address of string to print "Now Cookie is "
syscall # print the string


li $v0, 1 # system call code for print_int
la $a0, 5 # address of int to print 5 CookiesAge
syscall # print the integer

li $v0, 4 # system call code for print_str
la $a0, YearsOld # address of string to print "years old."
syscall # print the string

li $v0, 4 # system call code for print_str
la $a0, NewLine # address of string to print "\n" New line.
syscall # print the string

li $v0, 4 # system call code for print_str
la $a0, NewLine # address of string to print "\n" New line.
syscall # print the string


li $v0, 4 # system call code for print_str
la $a0, Meow # address of string to print "Meow."
syscall # print the string

li $v0, 4 # system call code for print_str
la $a0, NewLine # address of string to print "\n" New line.
syscall # print the string

li $v0, 4 # system call code for print_str
la $a0, Purry1 # address of string to print "Purry is a cat
# who is "
syscall # print the string

li $v0, 1 # system call code for print_int
la $a0, 1 # address of int to print 1 PurrysAge
syscall # print the integer

li $v0, 4 # system call code for print_str
la $a0, YearsOld # address of string to print "years old."
syscall

li $v0, 4 # system call code for print_str
la $a0, NewLine # address of string to print "\n" New line.
syscall # print the string

li $v0, 4 # system call code for print_str
la $a0, Meow # address of string to print "Meow."
syscall # print the string


li $v0, 4 # system call code for print_str
la $a0, NewLine # address of string to print "\n" New line.
syscall # print the string


li $v0, 4 # system call code for print_str
la $a0, Purry2 # address of string to print "Now Purry is "
syscall

li $v0, 1 # system call code for print_int
la $a0, 2 # address of int to print 2 PurrysAge
syscall # print the integer


li $v0, 4 # system call code for print_str
la $a0, YearsOld # address of string to print "years old."
syscall # print the string

li $v0, 4 # system call code for print_str
la $a0, NewLine # address of string to print "\n" New line.
syscall # print the string



# End of main() program



#Cat program output:

# Meow.
# Cookie is a cat who is 3 years old.
# Meow.
# Now Cookie is 5 years old.

# Meow.
# Purry is a cat who is 1 years old.
# Meow.
# Now Purry is 2 years old.

shwaip

Ok, I've never used MIPS to print things, but I've got a pretty good handle on what's going on:

li $v0, 1                #preps for printing
la $a0, whatToPrint #Loads the [b]Address[/b] of what to print
syscall                  #does the actual printing

You're going to need to store the each of the cats age in memory if you want to print it. I would create a .word for each of the cats age. When you call the constructor, set the cat's age in memory, and then when you try to print it, it should work.

f15e

Thanks for your help. I have seen .word before but have never used it. I have a book "Computer Organization & Design: The Hardware/Software Interface" and it doesn't mention how to use .word as far as I can tell.
Anyway, I have seen it used as follows:

.word 2, 1, 3, 5, 4, etc.......

What exactly is the .word doing and what do the numbers mean?


Thanks again!!

shwaip

it goes in the .data section

if you want to store a single value, with a label

LABEL: .word value

if you want to store an array

LABEL: .word value1,value2...

you're just storing a value to memory.

f15e

I believe this will help. I really appreciate you taking time to help me out.
THANKS!!

shwaip

np

If you have any more questions, feel free to post them.