Most operating systems provide interrupt facilities, sometimes called signals either generated by the user or as a result of program failure or reaching a limit like file space.
Unhandled signals generally terminate a program in a disorderly manner.
Signal handlers are created so that the program behaves in a well-defined manner upon receipt of a signal.

Task

Provide a program that displays an integer on each line of output at the rate of about one per half second.
Upon receipt of the SIGINT signal (often generated by the user typing ctrl-C ( or better yet, SIGQUIT ctrl-\ )) the program will cease outputting integers, output the number of seconds the program has run, and then the program will quit.




 
%define sys_signal 	48
%define SIGINT			2
%define sys_time	13
 
extern usleep
extern printf
 
section .text
	global _start
 
	_sig_handler:
		mov ebx, end_time
		mov eax, sys_time
		int 0x80
		mov eax, dword [start_time]
		mov ebx, dword [end_time]
		sub ebx, eax
		mov ax, 100
		div ebx
		push ebx
		push p_time
		call printf
		push 0x1
		mov eax, 1
		push eax
		int 0x80
		ret
 
	_start:
		mov ebx, start_time
		mov eax, sys_time
		int 0x80
		mov ecx, _sig_handler
		mov ebx, SIGINT
		mov eax, sys_signal
		int 0x80
		xor edi, edi
		.looper:
			push 500000
			call usleep
			push edi
			push p_cnt
			call printf
			inc edi
		jmp .looper
 
section .data
p_time	db "The program has run for %d seconds.",13,10,0
p_cnt		db "%d",13,10,0
 
section .bss
start_time	resd 1
end_time		resd 1
 