Argthtjtr

did some searching and couldn't quite find a definitive answer on this. I'm trying to display a string of text onto the MMIO simulator in assembly language (mars 4.5 ide). So in the code I ask the user to input a string, then I jump to a function that will access the appropriate register to achieve this. Heres my code so far

.data



# Do an inputted string text.

    input1: .asciiz "Please enter a string: "

# Make enough space for the array.

    array1: .space 101

# Resulting string.

    output1 :.asciiz "nInputted string from MMIO: "



.text



# Display the first input and the resulting string.

    li $v0, 4

    la $a0, input1

    syscall

    li $v0, 8

    la $a0, array1

    la $a1, 101

    syscall

# Move the address of the first element in a temporary register.

    la $t0, ($a0)



# Now store some items on the stack.

    addiu $sp, $sp, -12

    sw $ra, ($sp)

    sw $t0, 4($sp)





# Then call the function to print that output back using a mock syscall

    jal print_line



# Restore whats on the stack.

    lw $ra, ($sp)

    lw $t0, 4($sp)

    addiu $sp, $sp, 12





# Terminate the program.

    li $v0, 10

    syscall



# Define the key_getter function.

print_line:



# Now load some stuff from the stack into this area.

    lw $a1, 4($sp)



# Then gather the hard coded memory address of the display terminal

    li $a2, 0xffff0000



# At this point, $a1 holds the memory address of the first element in the string.

# And $a2 holds the memory address of the display register for the MMIO.



loop:

#####

display_not_ready:



# Load the word from our display terminal with an offset of 8.

    lw $t0, 8($a2)

# Then isolate the bit at the very end.

    andi $t0, $t0, 1

# This means if the bit is 1, then the display is ready, if not branch

# until it is ready.

    beqz $t0, loop



# Check it the 12th offset is a new line if it is branch to done.

    lw $t1, 12($a2)

    beq $t1, 10, done



# If we've reached this far then there is a character ready to print.

    sw $t1, 12($a2)

# Move to the next character in the array.

    addi $a1, $a1, 1 

# Then branch back up to loop.

    b loop

# Have our done ready.

done:

jr $ra

The problem: Whenever I assemble the code and enter the string, my program gets stuck in an infinite loop around the memory address of "display_not_ready" and beqz $t0, loop.

And it never displays the string to the MMIO simulator in the display field.

Note: After reading a few of the answers on this website, yes I always make sure that the "connect to mips" button is activated. This is not the problem.