%include "IO_DEFS.asm"

; Because my memory is not working
;   x /11g $rsp
section .data
        limit   dq 9 
        output  db `The top of the stack was x\n`
        size    equ $ - output

section .bss

section .text
   global _start

_start:
    ;  r10d will hold the address of the space to write to in the  output buffer
    ;  r8 will be used to push values onto the stack


    ;********************************************************
    ;for(r8  = 9; r8 > 0; --r8)
    ;   push(r8)
    ;********************************************************

    mov r8, [limit]
top_push_loop:
    push r8
    dec  r8
    test  r8, r8
    jnz  top_push_loop

    ; some book keeping for the loop.
    ; we don't need to do this every time in the loop.
    lea esi, [output]     ; the base address of the string
    mov edx, size         ; the size of the string
    mov edi, STDOUT       ; destination
    lea r10d, [output+size-2]

    ;********************************************************
    ; do 
    ;     r9 = pop()
    ;     cout << "The top of the stack was " << r9 << endl;
    ; while r9 != 9
    ;********************************************************

top_pop_loop:
    ; r9 will hold values removed from the stack
    ; bx will be used to convert the value to a character

    pop   r9 

    ; convert this to ascii
    ; rdi holds the 
    mov   rbx, r9
    add   bl, '0'
    mov  [r10d], bl

    ; print the value
    ; remember, eax gets overwritten by the number of characters read
    ; so it needs to be restored each time
    mov eax, SYS_WRITE
    syscall

    cmp r9, [limit] 
    jne top_pop_loop

    ; Exit
    mov eax, SYS_EXIT
    mov edx, SUCCESS
    syscall