fibonacci.asm

;; fibonacci.asm ;;
;; print fibonacci numbers up to 1000000000	;;
global _start

section .bss

array2 resb 512					;for converted output

section .text

;;;;;;;;;;;;;;;;;;;;;; FIBONACCI GENERATOR ;;;;;;;;;;;;;;;;;;;;;;;;;;
input:							;numbers will be stored in [input]
%assign i 1						;
%assign j 1						;
%rep 1000000000					;lim of fibonacci num - 1
	%if j > 1000000000			;
		%exitrep				;
	%endif						;
								;
	dd j						;
								;
	%assign k j+i				;
	%assign i j					;
	%assign j k					;
%endrep							;
inlen equ ($-input)/4			;amount of 4 byte elements 

;;;;;;;;;;;;;;;;;;;;;;; MAIN PART ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
_start:
		xor ecx, ecx			;stack depth counter
		mov edi, -1				;crutch for cell in input counter
		mov esi, -1				;crutch for place in output counter

cycle:							;main cycle
		mov [array2+esi],byte 10;put \r in output after each number
		inc esi					;place in output counter ++

		inc edi					;new 4 byte cell from input
		cmp edi, inlen			;input ended?
		jz exit					;	if YES, go to exit
		
		mov eax, [input+edi*4]	;if NO, prepare to divide eax by
		mov ebx, 10				;	ebx (123 -> 1,2,3)

;;;;;;;;;;;;;;;;;;;;;;; PROCESS 1 CELL OF INPUT ;;;;;;;;;;;;;;;;;;;;;
chop:							;123 -> 1,2,3
		xor edx, edx			;prepare EDX:EAX
		div ebx					;divide eax by ebx
		add edx, 00110000b		;convert remainder to ascii
		test eax, eax			;is anything left to divide
		jnz prpchop				;if YES -> prepare to do it again

transf:							;if NO -> transfer to output array
		mov [array2+esi], dl	;move it to array, only 1 byte
		inc esi					;place in output array ++
		test ecx, ecx			;anything to add in stack?
		jz cycle				;if NO -> go for next cell
		pop edx					;if YES -> pull it out
		dec ecx					;stack depth --
		jmp transf				;transfer to output array

prpchop:						;prepare to chop again
		push edx				;save prev remainder from division
		inc ecx					;stack depth counter ++
		xor edx, edx			;prepare EDX
		jmp chop				; -> chop

exit:							;almost done ^_^

;;;;;;;;;;;;;;;;;;;;;;; OUTPUT LENGTH CALCULATION ;;;;;;;;;;;;;;;;;;;;
		xor ecx, ecx			;prepare counter
lp:		cmp byte [array2+ecx],0 ;end of output array?
		jz end					;if YES -> stop count
		inc ecx					;if NO -> keep count
		jmp lp					;do it again
end:							;done ^_^
		
;;;;;;;;;;;;;;;;;;;;;;; PRINT AND EXIT ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
		mov eax, 4		;write
		mov ebx, 1		;	to standard output
		mov ecx, array2	;	start of output array
		mov edx, ecx	;	length of output array
		int 80h			;	syscall (do it)

		mov eax, 1		;exit
		mov ebx, 1		;	all ok
		int 80h			;	do it