triangle.nasm

    global _start
    section .text

stdout equ 1

_start:
    mov r8, 1 ; initial line length
    mov r9, 0 ; chars written
    mov rdx, buffer

line:
    mov byte [rdx], '*'
    inc rdx
    inc r9
    cmp r9, r8 ; check if number of written stars is same as needed
    jne line

lineDone:
    mov byte [rdx], `\n`
    inc rdx
    inc r8
    mov r9, 0
    cmp r8, maxlines
    jng line

print:
    mov byte [rdx], `\n`
    inc rdx
    sub rdx, buffer

    mov rax, 1
    mov rdi, stdout
    mov rsi, buffer
    syscall
    mov       rax, 60  ; system call for exit
    xor       rdi, rdi ; exit code 0
    syscall

    section .bss
maxlines    equ     8
buffer_size equ     64
buffer:     resb    buffer_size