circle.s

	.text
	.globl	_main
_main:
	call	___djgpp_nearptr_enable
	testl	%eax, %eax
	jz	err
	movw	$0x13, %ax
	int	$0x10
	movl	$0xa0000, %ebx
	subl	___djgpp_base_address, %ebx
	# Fill background
	pushl	$(320 * 200)
	pushl	$17
	pushl	%ebx
	call	_memset
	addl	$12, %esp
	# Draw circles
	movl	$75, %ecx
l2:	pushl	%ecx
	call	_circle
	popl	%ecx
	subl	$5, %ecx
	testl	%ecx, %ecx
	jnz	l2
	call	_getch
	movw	$0x3, %ax
	int	$0x10
	call	___djgpp_nearptr_disable
	xorl	%eax, %eax
	ret
err:	movl	$1, %eax
	ret
	.globl	_circle
_circle:
	pushl	%ebp
	movl	%esp, %ebp
	subl	$8, %esp
	# Square radius
	movl	8(%ebp), %eax
	imull	%eax
	# Start at bottom (WRONG!!!)
	movl	8(%ebp), %ecx
	negl	%ecx
l:
	# Square y and take difference
	movl	%ecx, %edx
	imull	%edx, %edx
	negl	%edx
	addl	%eax, %edx
	movl	%edx, -4(%ebp)
	# Find square root
	fildl	-4(%ebp)
	fsqrt
	fistpl	-4(%ebp)
	# Get screen coordinates
	movl	$100, %edx
	subl	%ecx, %edx
	imull	$320, %edx
	addl	%ebx, %edx
	movl	%edx, -8(%ebp)
	addl	-4(%ebp), %edx
	addl	$160, %edx
	movb	$6, (%edx)
	movl	$160, %edx
	subl	-4(%ebp), %edx
	addl	-8(%ebp), %edx
	movb	$6, (%edx)
	cmpl	%ecx, 8(%ebp)
	pushf			# So sorry
	incl	%ecx
	popf
	jne	l
	leave
	ret
	.data
n256:	.long	256