.text
.globl  _start

start = 0
max = 31

_start:
        mov     $start,%r15     /* starting value for loop */
        mov     $0x30,%r12         /* value of 0 in hex to ascii*/


loop:
        // division for 2-digit number
        mov     $0,%rdx         /* clear remainder for division */
        mov     %r15,%rax       /* set rax to be divided */
        mov     $10,%r10        /* set divisor */
        div     %r10            /* divide */
        mov     %rax,%r14       /* store quotient */
        mov     %rdx,%r13       /* store remainder */

        // modify msg
        add     $0x30,%r14      /* convert to ascii */
        add     $0x30,%r13      /* convert to ascii */
        mov     %r13b,msg+7     /* modify single byte in msg */

        // skip if first digit is 0
        cmp     %r12,%r14
        je      print
        mov     %r14b,msg+6     /* modify single byte in msg */

print:
        // print out
        mov     $len,%rdx       /* length of string */
        mov     $msg,%rsi       /* string */
        mov     $1,%rdi         /* stdout */
        mov     $1,%rax         /* write */
        syscall

        // loop
        inc     %r15            /* increment register */
        cmp     $max,%r15       /* compare max to increment value */
        jne     loop            /* back to loop if not equal */

        // exit
        mov     $0,%rdi         /* exit status */
        mov     $60,%rax        /* syscall 60 = exit */
        syscall

.data
msg:    .ascii  "Loop:   \n"
len = . - msg