[GNU assembly] cannot store a number in a data

.global main

.section .data

debug_msg1: .asciz "True"
debug_msg1_len = . - debug_msg1

format: 
    .ascii "results is %d\n"
format_len = 10

message_0:
    .asciz "Hello, World!\n"
message_0_len = . - message_0


message_1:
    .asciz "Enter mode +,-,*,/: "
message_1_len = . - message_1

message_2: 
    .asciz "enter the first num: "
message_2_len = . - message_2

message_3: 
    .asciz "enter the second num: "
message_3_len = . - message_3

message_4: 
    .asciz "results is "
message_4_len = . - message_4

.section .bss
    num1: .skip 10
    num2: .skip 10
    operator: .skip 1
    .lcomm results, 10
.section .text
main:
    // Writes "Hello, world!"
    ldr x1, =message_0  // Load the address of the message
    ldr x2, =message_0_len       // Length of the message
    bl print
    
    /* prompts mode */
    ldr x1, =message_1
    ldr x2, =message_1_len
    bl print

    // takes input
    ldr x1, =operator
    ldr x2, =10
    bl input
    
    /* fake input to handle enter press
    ldr x1, =temp
    ldr x2, =1
    bl input*/
    /* end prompt mode */

    /* prompts first num */
    ldr x1, =message_2
    ldr x2, =message_2_len
    bl print
    
    // takes input
    ldr x1, =num1
    ldr x2, =10
    bl input
    /* end prompt first num */

    /* prompts second num */
    ldr x1, =message_3
    ldr x2, =message_3_len
    bl print
    
    // takes input
    ldr x1, =num2
    ldr x2, =10
    bl input
    /* end prompt second num */
    //prints operator
    /* results */

    ldr x1, =operator
    
    //prints x1 to make sure its correct
    ldr x2, =20
    bl print
    

    
    ldrb w0, [x1]
    sub w0, w0, 0x0 // refresh w0 so it doesnt change when x1 change
    
    ldr x1, =num1
    ldrb w3, [x1]
    sub w3, w3, '0' // converts results to number && ^^

    ldr x1, =num2
    ldrb w4, [x1]
    sub w4, w4, '0' // ^^
    
    cmp w0, #'+'
    
    beq add
    /* end results */

    // Exit the program
    bl exit
print:
    mov x0, 1 // file descriptor STDOUT
    mov w8, 64 // sys call sys write
    svc #0 // invoke syscall
    
    ret // branch back to [lr](in this case its _start)

input: 
    mov x0, 0 // file descriptor STDIN
    mov w8, #63 // syscall sys read
    svc #0
    
    
    ret
add: 
    ldr x1, =results
    
    add w3, w3, w4
    
    str w3, [x1] 
    sub sp, sp, #16

    ldr x0, =format
    
    ldr x2, =10
    bl printf

    add sp, sp, #16

    bl exit
exit: 
    mov w8, #93 // syscall exit
    mov x0, #0 // exit status
    svc #0
true:
    ldr x1, =debug_msg1
    ldr x2, =debug_msg1_len
    bl print
    ret
exit_err:
    mov w8, #93
    mov x0, #1
    svc #0