; sys_write(fd, buf, buflen)
%macro sys_write 3 
    mov     rax,1   ; system call number
    mov     rdi,%1  ; arg1: fd
    mov     rsi,%2  ; arg2: buffer
    mov     rdx,%3  ; arg3: buflen
    syscall
%endmacro

; sys_read(fd, buf, buflen)
%macro sys_read 3 
    mov     rax,0   ; system call number
    mov     rdi,%1  ; arg1: fd
    mov     rsi,%2  ; arg2: buffer
    mov     rdx,%3  ; arg3: buflen
    syscall
%endmacro