Linux 64 FASM coding

Hello, hot and necessary package for every Linux64 Flat Assembler coder.
One big please to Tomasz Grysztar - would you update Hello64 sample, please?
The way of asm coding in memory over old 32-bit limit is by syscall, but not int80 because int80 isn't able to access memory over 32-bit (maybe truncate 64-bit reg to 32-bit ?)
Of course int80 works perfectly up to 32-bit memory limit.

Code:

; fasm demonstration of writing 64-bit ELF executable

; syscall numbers: /usr/src/linux/include/asm-x86_64/unistd.h
; parameters order:
; r9    ; 6th param
; r8    ; 5th param
; r10   ; 4th param
; rdx   ; 3rd param
; rsi   ; 2nd param
; rdi   ; 1st param
; eax   ; syscall_number
; syscall

format ELF64 executable at 0000000100000000h    ; put image over 32-bit limit

segment readable executable

entry $

        mov     edx,msg_size    ; CPU zero extends 32-bit operation to 64-bit
                                ; we can use less bytes than in case mov rdx,...
        lea     rsi,[msg]
        mov     edi,1           ; STDOUT
        mov     eax,1           ; sys_write
        syscall

        xor     edi,edi         ; exit code 0
        mov     eax,60          ; sys_exit
        syscall

segment readable writeable

msg db 'Hello 64-bit world!',0xA
msg_size = $-msg