////////  factorial.s
	.section	.rodata
.InputMsg:
	.string	"Input number : "
.ErrorMsg:
	.string	"Incorrect number\n"
.InputMask:
	.string	"%u"
.OutputMsg:
	.string	"Answer: %u\n"
.TooBigMsg:
	.string	"Number too big\n"

	.text
	.type	factorial, @function
factorial:
	enter	$ 4 ,$ 0 
	pushl	%edx
	cmpl	$ 1 ,  8 (%ebp)
	jle	.L2
	movl	 8 (%ebp), %eax
	subl	$ 1 , %eax
	movl	%eax, (%esp)
	call	factorial
	xorl	%edx, %edx
	imull	 8 (%ebp)
	test	%edx,%edx
	jz	.L4
	xorl	%eax,%eax
.L4:
	movl	%eax, - 4 (%ebp)
	jmp	.L3
.L2:
	movl	$ 1 , - 4 (%ebp)
.L3:
	movl	- 4 (%ebp), %eax
	popl	%edx
	leave
	ret
	
	.text
.globl main
	.type	main, @function
main:
	enter	$ 4 ,$ 0 
	
	pushl	$.InputMsg
	call	printf
	add	$ 4 ,%eax

	leal	- 4 (%ebp),%eax
	push	%eax
	pushl	$.InputMask
	call	scanf
	addl	$ 8 ,%esp

	test	%eax,%eax
	jnz	.correct
	pushl	$.ErrorMsg
	call	printf
	addl	$ 4 ,%esp
	movl	$ 1 ,%eax
	jmp	.exit

.correct:
	movl	- 4 (%ebp),%eax
	pushl	%eax
	call	factorial
	addl	$ 4 , %esp
	test	%eax,%eax
	jnz	.correct2
	pushl	$.TooBigMsg
	call	printf
	addl	$ 4 , %esp
	movl	$ 1 , %eax
	jmp	exit
.correct2:
	pushl	%eax
	pushl	$.OutputMsg
	call	printf
	addl	$ 8 ,%esp
	
	xorl	%eax, %eax
.exit:
	leave
	ret