I am trying to come up with a basic "if yes then do this, if no then exit" algorithm in mips (using spim simulator). However, bne always branches off whether yes or no (y or n in this case) has been given. I am very new to mips, so I am probably missing something big... or small I don't know. Here is what I have:
.data
welcome: .asciiz "Hello World!\n"
begin: .asciiz "\nEnter a mathematical operator: "
question: .asciiz "\nWould you like to solve a problem (y/n)? "
back: .asciiz "You wrote "
buffer: .space 2
yes: .asciiz "y"
exiting: .asciiz "exiting"
.text
.globl main
main:
li $v0, 4 # syscall 4 (print_str)
la $a0, welcome # argument: string
syscall # print the string
Loop:
# ASK IF WANT TO SOLVE A QUESTION
li $v0, 4 # syscall 4 (print_str)
la $a0, question # argument: string
syscall
# GET INPUT FROM USER
li $v0, 8 # get input
la $a0, buffer # load byte space into address
li $a1, 2 # allot the byte space for string
move $t0,$a0 # save string to t0
syscall
#EDIT
lb $t1, yes #previously la $t1, yes
lb $t0, 0($t0) #new
#END EDIT
bne $t0, $t1, Exit
########IF YES, PRINT MESSAGE
########this code is only for testing and doesn't really mean anything
########so you can ignore it
li $v0, 4 # syscall 4 (print_str)
la $a0, begin # argument: string
syscall
li $v0, 8 #get input
la $a0, buffer #load byte space into address
li $a1, 20 # allot the byte space for string
move $t0,$a0 #save string to t0
syscall
la $a0,back #load and print "you wrote" string
li $v0,4
syscall
la $a0, buffer #reload byte space to primary address
move $a0,$t0 # primary address = t0 address (load pointer)
li $v0,4 # print string
syscall
j Loop
########### END IF YES
Exit:
li $v0, 4
la $a0, exiting
syscall
li $v0, 10
syscall
jr $ra # return to caller
So the issue is that $t0 and $t1 are never equal, regardless of what the user inputs. What do I need to do to properly compare the two values?
I believe you need to change the line:
la $t1, yes
to
lb $t1, yes