/* To build and run this:
as fun_hello_world.s -o fun_hello_world.o --32
ld -m elf_i386 fun_hello_world.o
./a.out
*/

.section .data
hwmessage: 
	.asciz "Hello World\n"
.section .text
.globl _start
_start:
	push $5
	call print_number
	call print_newline
	call print_newline
	call print_newline
	call print_newline
	movl $27, %ebx
	movl $1, %eax
	int $0x80

/* Print "hello world" a given number of times
	We'll follow 32-bit C calling convention and put the paramter on the stack
*/

print_newline:
	push $0x0a
	movl $4, %eax
	movl $1, %ebx
	movl %esp, %ecx
	movl $1, %edx
	int $0x80
	add $4, %esp
	ret

print_number:
	push %ebp
	mov %esp, %ebp
	// We'll have one local variable, and it'll be the address of the last non-0 character

	sub $16, %esp
	movl 8(%ebp), %eax # Puts our parameter into eax

	movl $10, %ecx
	
loop_top:
	dec %ecx
	movl $0, %edx
	movl $10, %ebx
	div %ebx
	add $48, %edx
	mov %esp, %esi
	add %ecx, %esi
	cmp $48, %edx
	je skip_address_update
	# Save this as the last non-0 digit's address
	mov %esi, 12(%esp)
skip_address_update:
	movb %dl, (%esi)
	
	cmp $0, %ecx
	jne loop_top

	movl $4, %eax
	movl $1, %ebx
	movl 12(%esp), %ecx
	mov %ecx, %edx
	sub %esp, %edx
	mov $10, %esi
	sub %edx, %esi
	mov %esi, %edx	
	
	int $0x80

	
	mov %ebp, %esp
	pop %ebp	
	ret