Indenting mainloop

wtfstopw.asm

@@ -1,3 +1,23 @@
+;WTFStopW : a simple stopwatch
+;Copyright (C) 2018 Weber Yann
+;
+;This program is free software; you can redistribute it and/or modify
+;it under the terms of the GNU General Public License as published by
+;the Free Software Foundation; either version 3 of the License, or
+;any later version.
+;
+;This program is distributed in the hope that it will be useful,
+;but WITHOUT ANY WARRANTY; without even the implied warranty of
+;MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;GNU General Public License for more details.
+;
+;You should have received a copy of the GNU General Public License
+;along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+; A simple precise stopwatch
+; Build with : 
+; nasm -felf64 wtfstopw.asm && ld wtfstopw.o -o wtfstopw
+
 [bits 64]
 
 section .text
@@ -7,15 +27,14 @@ _start:
 
 ; set stdin non blocking
 xor rdx, rdx
+xor rdi, rdi
 mov rax, 72 ; fcntl
-mov rdi, 0 ; stdin
 mov rsi, 3 ; F_GETFL
 syscall
 mov rdx, rax
 or rdx, 0x800 ; O_NONBLOCK
 dbg:
 mov rax, 72 ; fcntl
-mov rdi, 0 ; stdin
 mov rsi, 4 ; F_SETFL
 syscall
 cmp rax, 0
@@ -28,144 +47,140 @@ syscall
 
 
 print_time:
+	; updating ts_cur time
+	mov rax, 228 ; clock_gettime
+	mov rdi, 0 ; CLOCK_REALTIME
+	mov rsi, ts_cur
+	syscall
 
-; updating ts_cur time
-mov rax, 228 ; clock_gettime
-mov rdi, 0 ; CLOCK_REALTIME
-mov rsi, ts_cur
-syscall
+	mov rax, [tv_cur_us]
+	mov rbx, [tv_start_us]
+	sub rax, rbx
+	cmp rax, 0
+	jge print_time_us_cont
+	; negativ result
+	add rax, 1000000000
+	mov rbx, [tv_cur_s]
+	sub rbx, 1
+	mov [tv_cur_s], rbx
+	print_time_us_cont:
+	xor rdx, rdx
+	mov rcx, 100000
+	div rcx
+	; set the us char in timestr
+	mov r8, timestr
+	add r8, 10 ; r8 points on last char before \r
+	mov r9, 4 ; r9 count the number of digits
+	print_time_us_loop:
+		xor rdx, rdx
+		mov rcx, 10
+		div rcx
+		add dl, 0x30
+		mov [r8], dl
+		sub r8, 1
+		sub r9, 1
+		cmp r9, 0
+		jg print_time_us_loop
+
+	; handling seconds, minutes & hours
+	mov rax, [tv_cur_s]
+	mov rbx, [tv_start_s]
+	sub rax, rbx
+	; rax now contain elapsed seconds
+	; filling timestr with seconds & minutes
 
-mov rax, [tv_cur_us]
-mov rbx, [tv_start_us]
-sub rax, rbx
-cmp rax, 0
-jge print_time_us_cont
-; negativ result
-add rax, 1000000000
-mov rbx, [tv_cur_s]
-sub rbx, 1
-mov [tv_cur_s], rbx
-print_time_us_cont:
-xor rdx, rdx
-mov rcx, 100000
-div rcx
-; set the us char in timestr
-mov r8, timestr
-add r8, 10 ; r8 points on last char before \r
-mov r9, 4 ; r9 count the number of digits
-print_time_us_loop:
 	xor rdx, rdx
 	mov rcx, 10
 	div rcx
 	add dl, 0x30
-	mov [r8], dl
-	sub r8, 1
-	sub r9, 1
-	cmp r9, 0
-	jg print_time_us_loop
-
-; handling seconds, minutes & hours
-mov rax, [tv_cur_s]
-mov rbx, [tv_start_s]
-sub rax, rbx
-; rax now contain elapsed seconds
-; filling timestr with seconds & minutes
+	mov byte [timestr + 5], dl
 
-xor rdx, rdx
-mov rcx, 10
-div rcx
-push rax
-mov rax, rdx
-add al, 0x30
-mov byte [timestr + 5], al
-
-pop rax
-xor rdx, rdx
-mov rcx, 6
-div rcx
-push rax
-mov rax, rdx
-add al, 0x30
-mov byte [timestr + 4], al
-
-pop rax
-xor rdx, rdx
-mov rcx, 10
-div rcx
-push rax
-mov rax, rdx
-add al, 0x30
-mov byte [timestr + 2], al
-
-pop rax
-xor rdx, rdx
-mov rcx, 6
-div rcx
-push rax
-mov rax, rdx
-add al, 0x30
-mov byte[timestr + 1], al
-
-; filling the hours buffer
-; r8 will contain our digits counter : max is 8
-mov r8, 8
-pop rax
-print_time_hours_loop:
-	mov rcx, 10
+	pop rax
 	xor rdx, rdx
+	mov rcx, 6
 	div rcx
-	add dl, 0x30
-	cmp rax, 0
-	jne print_time_hours_print_mod
-	cmp rdx, 0
-	je print_time_hours_loop_end
+	push rax
+	mov rax, rdx
+	add al, 0x30
+	mov byte [timestr + 4], al
+
+	pop rax
+	xor rdx, rdx
+	mov rcx, 10
+	div rcx
+	push rax
+	mov rax, rdx
+	add al, 0x30
+	mov byte [timestr + 2], al
 
-	print_time_hours_print_mod:
+	pop rax
+	xor rdx, rdx
+	mov rcx, 6
+	div rcx
+	push rax
+	mov rax, rdx
+	add al, 0x30
+	mov byte[timestr + 1], al
+
+	; filling the hours buffer
+	; r8 will contain our digits counter : max is 8
+	mov r8, 8
+	pop rax
+	print_time_hours_loop:
+		mov rcx, 10
+		xor rdx, rdx
+		div rcx
+		add dl, 0x30
+		cmp rax, 0
+		jne print_time_hours_print_mod
+		cmp rdx, 0
+		je print_time_hours_loop_end
+
+		print_time_hours_print_mod:
+		mov r9, hours
+		add r9, r8
+		mov byte [r9], dl
+		cmp r8, 0
+		je fault
+		sub r8, 1
+		cmp rax, 0
+		jne print_time_hours_loop
+	print_time_hours_loop_end:
+
+	; print hours + timestr
+	add r8, 1
+	cmp r8, 7
+	jle print_time_hours_cont
+	mov r8, 7
+	print_time_hours_cont:
 	mov r9, hours
 	add r9, r8
-	mov byte [r9], dl
-	cmp r8, 0
-	je fault
-	sub r8, 1
-	cmp rax, 0
-	jne print_time_hours_loop
-print_time_hours_loop_end:
-
-; print hours + timestr
-add r8, 1
-cmp r8, 7
-jle print_time_hours_cont
-mov r8, 7
-print_time_hours_cont:
-mov r9, hours
-add r9, r8
-mov rcx, 9
-sub rcx, r8
-add rcx, timestrlen
-
-mov rax, 1 ; write
-mov rdi, 1 ; stdout
-mov rsi, r9
-mov rdx, rcx
-syscall
+	mov rcx, 9
+	sub rcx, r8
+	add rcx, timestrlen
+
+	mov rax, 1 ; write
+	mov rdi, 1 ; stdout
+	mov rsi, r9
+	mov rdx, rcx
+	syscall
 
-; Attempt to read from stdin
-; if something read, enter has been pressed
-mov rax, 0
-mov rdi, 0
-mov rsi, buf
-mov rdx, 1
-syscall
-cmp rax, 0
-jge flush_stdin ; flush stdin and exit
+	; Attempt to read from stdin
+	; if something read, enter has been pressed
+	mov rax, 0
+	mov rdi, 0
+	mov rsi, buf
+	mov rdx, 1
+	syscall
+	cmp rax, 0
+	jge flush_stdin ; flush stdin and exit
 
-sleep:
-	mov rax, 35
+	mov rax, 35 ; nanosleep
 	mov rdi, ts_sleep
 	mov rsi, 0
 	syscall
 
-jmp print_time ; main loop
+	jmp print_time ; main loop
 
 flush_stdin:
 	mov rax, 0
@@ -182,6 +197,16 @@ exit:
 	mov rdi, 0 ; OK
 	syscall
 fault:
+	mov rax, 1 ; write
+	mov rdi, 2 ; stderr
+	mov rsi, nl
+	mov rdx, 1
+	syscall
+	mov rax, 1
+	mov rsi, faultmsg
+	mov rdx, faultmsglen
+	syscall
+
 	mov rax, 60 ; sys_exit
 	mov rdi, 1 ; failure
 	syscall
@@ -201,6 +226,8 @@ ts_start:
 	tv_start_s dq 0
 	tv_start_us dq 0
 
+faultmsg: db "fault", 0xA
+faultmsglen: equ $ - faultmsg
 
 msg:	db "0 Hello, world!", 10
 msglen: equ $ - msg
@@ -226,5 +253,4 @@ ts_sleep:
 ;	tv_sleep_s dq 0
 ;	tv_sleep_us dq 500000000
 
-
 .end: