My Hello World Code In Assembly Language On Mac OS X

test.asm

; Assembling and linking
; ----------------------
; nasm -f macho64 test.asm
; gcc -o test test.o -Wl,-no_pie

            section     .data               ; data section
line1:
            db          "My name is: "      ; constant string
line2:
            db          "Ferdinand", 0xA    ; constant string with newline

            global      _main
            section     .text               ; text section

_main:
            mov         rax, 0x2000004      ; syscall number for write
            mov         rdi, 1              ; set first parameter to 1 (standard output)
            mov         rsi, line1          ; set second parameter to line1 constant string
            mov         rdx, 12             ; set third parameter (buffer size)
            syscall                         ; invoke write function

            mov         rax, 0x2000004      ; syscall number for write
            mov         rdi, 1              ; set first parameter to 1 (standard output)
            mov         rsi, line2          ; set second parameter to line2 constant string
            mov         rdx, 10             ; set third parameter (buffer size)
            syscall                         ; invoke write function

            mov         rax, 0x2000001      ; syscall number for exit
            mov         rdi, 0              ; set first parameter to 0 (return 0 to OS)
            syscall                         ; invoke exit function