More main_loop and _start code enhancement

wtfstopw.asm

 mov rax, 72 ; fcntl
 mov rsi, 3 ; F_GETFL
 syscall
-					mov rdx, O_NONBLOCK
-					not rdx
-					and rax, rdx
 mov [RBXPTR(fcntl_flag)], rax
 mov rdx, rax
-or rdx, O_NONBLOCK
+or dx, O_NONBLOCK
 mov rax, 72 ; fcntl
 mov rsi, 4 ; F_SETFL
 syscall
-cmp rax, 0
-jne fault
+test al, al
+js fault
 
 ; preparing SIGINT catch
 mov rax, proc_lap_handler
 setsleep_loopend:
 
 mov [RBXPTR(ts_sleep.tv_nsec)], rax
-mov r12, proc_print_time
-mov r10, 0x0d02
+mov r12w, 0x0d02
+mov r13, proc_print_time
+mov r14, buf ; nanosleep
+mov r15, ts_sleep
 
 std ; set DF for string operations
 
 align 16
 main_loop:
 
-	push rbx
-	push r10 ; \r & stderr
-	call r12
+	call r13 ; proc_print_time
 
-	pop rbx
-	; Attempt to read from stdin
+	; Attempt to read from stdin (syscall prepared by proc_print_time)
 	; if something read, enter has been pressed
-	xor rax, rax
-	push rax
-	push rax
-	pop rdi
-	mov rsi, rbx
-	add rsi, buf - ts_start
-	mov rdx, 1
 	syscall
-	test rax, rax
+	test al, al
 	jns flush_stdin ; flush & exit
-
+	
 	mov rax, 35 ; nanosleep
-	mov rdi, rbx
-	add rdi, ts_sleep - ts_start
-	pop rsi
+	mov rdi, r15
+	xor rsi, rsi
 	syscall
 
 jmp main_loop ; main_loop
 
 flush_stdin:
-	mov rax, 0
-	mov rdi, 0
-	mov rsi, buf
-	mov rdx, 1
+	xor rax, rax
+	;xor rdi, rdi ; done in main_loop
+	;mov rsi, r14
+	;mov rdx, 1
 	syscall
-	test rax, rax
+	test al, al
 	jz newline_exit
 	jns flush_stdin
 
-mov rdi, 0 ; EXIT OK
+	xor rbx, rbx ; EXIT OK
+	jmp exit
+
+	newline_exit:
+	call proc_nl
+	xor rbx, rbx ; exit OK
+	jmp exit
+
 ;
-; Expect rdi to be the return code
+; Expect rbx to be the return code
 ;
 exit:
-	push rdi
 	; restoring stdin state
 	mov rax, 72 ; fcntl
 	xor rdi, rdi
 	mov rsi, 4 ; F_SETFL
 	mov rdx, [fcntl_flag]
 	syscall
+	mov rdi, rbx ; return code
 	test rax, rax
-	jz exit_end
-	pop rdi ; failed to restore
-	push 1 ; exit FAIL
-
-	exit_end:
+	cmovnz rdi, rax ; exit FAIL
 	mov rax, 60 ; sys_exit
-	pop rdi ; return code
 	syscall
 fault:
 	mov rdi, 2 ; stderr
 	mov rdx, faultmsglen
 	syscall
 
-	mov rdi, 1 ; failure
+	mov rbx, 1 ; failure
 	jmp exit
-
-newline_exit:
-	mov rdi, 1
-	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
+; argument are in r12w r12b is FD and r12w(h) is CHR
 ; 	Warning : DF must be set
 ;
 align 16
 	xor rdx, rdx
 	div qword [RSIPTR(ts_sleep.tv_nsec)] ; Divide result given time_res
 
-	mov bl, [rsp + 9]
+	mov bx, r12w
+	shr bx, 8
 	mov byte [RSIPTR(timestrend - 1)], bl ; set last chr from 1st argument
 
 	; set the nanosec chars (time_res chars) in timestr
 		div rdi
 		shl rbx, 8
 		xchg bl, dl
-		cmp rax, 0
-		loopne procpt_looph
-	procpt_looph_end:
-
-	mov rax, HOURSLEN - 2
-	cmp rcx, HOURSLEN - 2
-	cmovl rax, rcx ; rsi stores hours digit count (at least 2)
-	cmp rcx, 0
+		test rax, rax
+		loopnz procpt_looph
+
+	xor rax, rax
+	mov al, HOURSLEN - 2
+	cmp cx, HOURSLEN - 2
+	cmovl ax, cx ; rax stores hours digit count (at least 2)
+	test cl, cl
 	jz procpt_looph2_end
-	procpt_looph2:
+	procpt_looph2: ; end rbx left shift before sto
 		shl rbx, 8
 		loopne procpt_looph2
 	procpt_looph2_end:
 	mov [RSIPTR(hours)], rbx
 
 	xor rdi, rdi
-	mov dil, [rsp + 8] ; fd as 2nd argument
+	mov dil, r12b ; fd as 2nd argument
 	mov rdx, timestrlen + HOURSLEN
 	sub rdx, rax ; timestr + hours len
 	lea rsi, [RSIPTR(hours + rax)] ; hours start pointer
 	test rax, rax
 	js fault
 
-	ret 8
+; ALLIGN TRICK : prepare read syscall for main_loop
+
+	xor rax, rax
+	xor rdi, rdi
+	mov rsi, r14
+	mov rdx, 1
+
+	ret
 %undef RSIPTR
 
 
 	js fault
 
 	std ; set DF for string operations
-	push 0x0A01 ; \n & stdout
+	mov r12w, 0x0A01 ; \n & stdout
 	call proc_print_time
 
 	ret