Factorisation + enhancement in proc_print_time

Writing a proc_nl function to print a newline on a given fd
Enhancement in argument passing to proc_print_time

wtfstopw.asm

 mov [ts_sleep.tv_nsec], rax
 
 main_loop:
-	push 2 ; stderr
-	push 0x0D ; \r
+	mov rax, 2 ; stderr
+	mov rdi, 0xD ; \r
 	call proc_print_time
 
 	; Attempt to read from stdin
 	pop rdi ; return code
 	syscall
 fault:
-	mov rax, 1 ; write
 	mov rdi, 2 ; stderr
-	mov rsi, nl
-	mov rdx, 1
-	syscall
+	call proc_nl
 	mov rax, 1
 	mov rsi, faultmsg
 	mov rdx, faultmsglen
 	jmp exit
 
 newline_exit:
-	mov rax, 1
 	mov rdi, 1
-	mov rsi, nl
-	mov rdx, 1
-	syscall
+	call proc_nl
 
 	mov rdi, 0 ; exit OK
 	jmp exit
 ;
 ; Print current time on FD and add a leading char CHR
 ; push FD & push CHR to set arguments
+; rax the FS & rdi the leading CHR
 ;
 proc_print_time:
-	; push ret addr before arguments
-	pop r8
-	pop r9
-	pop r10
-	push r8
-	push r10
-	push r9
+	
+	push rax
+	push rdi
 
 	; updating ts_cur time
 	mov rax, 228 ; clock_gettime
 
 	; Calculating elapsed ns
 	mov rax, [ts_cur.tv_nsec]
-	mov rbx, [ts_start.tv_nsec]
-	sub rax, rbx
+	sub rax, [ts_start.tv_nsec]
 	cmp rax, 0
 	jge print_time_us_cont
 	; negativ result
 	add rax, 1000000000
-	mov rbx, [ts_cur.tv_sec]
-	sub rbx, 1
-	mov [ts_cur.tv_sec], rbx
+	sub qword [ts_cur.tv_sec], 1
+
 	print_time_us_cont:
-	
 	; Divide result given time_res
 	mov r10, rax
 	mov rax, 1000000000
 	mov rdx, 3 ; " : "
 	syscall
 
-	push 1 ; stdout
-	push 0x0A ; \n
+	mov rax, 1 ; stdout
+	mov rdi, 0xA ; \n
 	call proc_print_time
 
 	ret
 	call proc_strlen
 	mov rax, 1
 	syscall
-	mov rax, 1
-	mov rsi, nl
-	mov rdx, 1
-	syscall
-	syscall
+	call proc_nl
+	call proc_nl
 	jmp arg_err
 
 ;
 	mov rdx, r9
 	ret
 
+; with rdi the fd
+proc_nl:
+	mov rax, 1
+	mov rsi, nl
+	mov rdx, 1
+	syscall
+	ret
+
 .end: