From 5091c3a0d5d2e3c2b7cd34a284457b58cc532ffe Mon Sep 17 00:00:00 2001
From: Yann Weber <yann.weber@member.fsf.org>
Date: Tue, 21 Aug 2018 17:51:38 +0200
Subject: [PATCH] Add a lap counter

---
 wtfstopw.asm | 65 ++++++++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 56 insertions(+), 9 deletions(-)

diff --git a/wtfstopw.asm b/wtfstopw.asm
index 7529a43..a4b841d 100644
--- a/wtfstopw.asm
+++ b/wtfstopw.asm
@@ -87,9 +87,13 @@ section .data
 	nl: db 0x0A
 	buf: db 0
 
-	lapsmsg: db 0x0d, "New lap : "
+	lapsmsg: db 0x0d, "Lap : "
 	lapsmsglen: equ $ - lapsmsg
 
+	lapcount: db "00000000"
+	lapcountlen: equ $ - lapcount
+	laplen: dq 2
+
 section .text
 global _start
 _start:
@@ -108,8 +112,10 @@ syscall
 cmp rax, 0
 jne fault
 
+; initializing lapptr
+
 ; preparing SIGINT catch
-mov rax, lap_handler
+mov rax, proc_lap_handler
 mov qword [sigaction.sa_handler], rax
 mov eax, 0x10000000 ; SA_RESTART
 or eax, 0x04000000 ; SA_RESTORER
@@ -134,7 +140,7 @@ syscall
 main_loop:
 	push 2 ; stderr
 	push 0x0D ; \r
-	call print_time
+	call proc_print_time
 
 	; Attempt to read from stdin
 	; if something read, enter has been pressed
@@ -193,7 +199,7 @@ newline_exit:
 ;
 ; Print current time on FD r10 and put r13b as leading char
 ;
-print_time:
+proc_print_time:
 	pop r8
 	pop r9
 	pop r10
@@ -317,19 +323,60 @@ print_time:
 
 	ret
 
-
-lap_handler:
+;
+;	sig handler for SIGINT displaying lap count and time on stdout
+;
+proc_lap_handler:
 	mov rax, 1
 	mov rdi, 1
 	mov rsi, lapsmsg
-	mov rdx, lapsmsglen
+	mov rdx, 5 ; "Lap "
+	syscall
+
+	; increment the lapcount str directly
+	mov rbx, lapcount ; first digit ptr
+	add rbx, lapcountlen ; rightmost digit ptr
+	sub rbx, 1
+	mov r8, 1 ; counter
+	lap_handler_inc_lap:
+		mov r10b, [rbx]
+		cmp r10b, 0x39 ; '9'
+		jl lap_handler_inc_end
+
+		add r8, 1
+		cmp r8, [laplen]
+		jl lap_handler_laplen_noupd
+		mov [laplen], r8 ; update laplen
+
+		lap_handler_laplen_noupd:
+		mov byte [rbx], 0x30 ; set current digit to '0'
+		sub rbx, 1
+		cmp rbx, lapcount
+		jl fault
+		jmp lap_handler_inc_lap
+	lap_handler_inc_end:
+		add r10b, 1
+		mov [rbx], r10b
+	
+
+	mov rax, 1
+	mov rdi, 1
+	mov rdx, [laplen]
+	mov rsi, lapcount
+	add rsi, lapcountlen
+	sub rsi, rdx ; leftmost digit ptr
+	syscall
+
+	mov rax, 1
+	mov rdi, 1
+	mov rsi, lapsmsg + 4
+	mov rdx, 3 ; " : "
 	syscall
 
 	push 1 ; stdout
 	push 0x0A ; \n
-	call print_time
+	call proc_print_time
 
-dbg2:
 	ret
 
 sig_restorer: