section .data
STDIN:      EQU     0
STDOUT:     EQU     1
STDERR:     EQU     2

SYS_READ:   EQU     0
SYS_WRITE:  EQU     1

; Because my memory is not working
;   x /11g $rsp

section .bss

        PRINT_INT_buffer resb 16

section .text
global PRINT_INT

PRINT_INT:

; this is a leaf routine, so we don't need to mess with the stack.
; Parameter:   rdi, the number to print

    mov rax, rdi

    lea edi, [PRINT_INT_buffer + 15]
    mov byte [edi], 0x0A

PRINT_INT_convert:
    dec edi                ; edi  scratch
    mov edx, 0             ; edx  scratch
    mov ecx, 10            ; ecx  scratch
    div ecx                ; eax = edx:eax/ecx edx = edx:eax%ecx
                           ; carter page 44
    add dl, '0'            ; dl + '0'   add ascii 0 to the digit
    mov [edi], dl          ; store the new character in edi buffer[14] = digit
    test eax, eax          ; check for any bits of eax not zero
                           ; carter page 51
    jnz PRINT_INT_convert

    mov esi, edi         ; edi needs the start position of the string.
                          
    lea edx, [PRINT_INT_buffer+16] ; edx needs the length of the string
                         ; the last character in the buffer.
    sub edx, edi         ; starting poisition - end position

    mov eax, SYS_WRITE
    mov edi, STDOUT      ; set the destination to stdout

    syscall

    ret