I am trying to write assembly language code for the following problem:
Write a program that uses a loop to calculate the first seven values of the Fibonacci number sequence described by the following formula: Fib(1) = 1, Fib(2) = 1, Fib(n) = Fib(n -1) +Fib(n-2).
Is my code correct? Also is it okay that I offset the numbers array and move it to the esi register before the loop?:
ExitProcess PROTO
.data
numbers DWORD 7 DUP (?)
.code
main PROC
mov ebx,0
mov edx,1
mov [numbers],edx
mov ecx,7
mov esi,4
mov esi,OFFSET numbers
L1:
mov eax,ebx
add eax,edx
mov [esi],edx
mov ebx,edx
mov edx,eax
add esi,4
Loop L1
call ExitProcess
main ENDP
END
The argument is passed via register EAX, and the value is returned through register EBX:
.code
mov eax,N ;calculate the N-th Fibonacci number
call fibonacci ;procedure call
invoke wsprintf,offset buffer,offset format, ebx
add esp,12 ; equalize stack after wsprintf
invoke MessageBox,0,offset buffer,offset caption,MB_OK;outputs the results to the screen
invoke ExitProcess,0; exit the program
;--------------------------------------
fibonacci proc
; EBX=F(N) - Fibonacci number with the number N (EAX=N)
cmp eax,1 ;If N> 1, go to the label f
ja f
mov ebx,1 ;if N<=1 then EBX=F(N)=1
retn
f: push eax ;save EAX
dec eax ;EAX=N-1
call fibonacci
push ebx ;save EBX=F(N-1)
dec eax ;EAX=N-2
call fibonacci;EBX=F(N-2)
pop eax ;EAX=F(N-1)
add ebx,eax ;EBX=F(N)=F(N-2)+F(N-1)
pop eax ;restore the original value in EAX
retn
fibonacci endp
;-----------------------------------------
.data
format db 'fibonacci=%u',0
buffer db 50 dup (0)
caption db 'fibonacci',0
QuoteIs my code correct?
no
QuoteAlso is it okay that I offset the numbers array and move it to the esi register before the loop?:
Yes, but ...
Check twice both lines below:
mov esi,4 ;I think you don't like to mov 4
mov esi,OFFSET numbers ;this line of code overwrite the meaning of line above
Check 7 times counter
You're doing first number on numbers table manually before loop, so ...
Check data section and/or variable
.data ==> initialized block (section) data
.data? ==> unitialized block (section) data
numbers DWORD 7 DUP (?) ==> interrogation means inside this scope unitialized data
ExitProcess PROTO
.data ;<------
numbers DWORD 7 DUP (?) ;<--------
.code
main PROC
mov ebx,0
mov edx,1
mov [numbers],edx ;first manually
mov ecx,7 ;starting counter
mov esi,4 ;supposed to point to next
mov esi,OFFSET numbers ;reseting esi register to start of numbers table
L1:
mov eax,ebx
add eax,edx
mov [esi],edx
mov ebx,edx
mov edx,eax
add esi,4
Loop L1
call ExitProcess ;ExitProcess function returns a number
main ENDP
END
Saudações, mineiro!
Eu ia escrever mais fácil...
N equ 10
.data
numbers dd 1,1, N-1 dup(?)
format 'fibonacci=%u',0
buffer db 50 dup (0)
caption db 'fibonacci',0
.code
start: mov ecx,N-1
mov esi,offset numbers+4
lea edi,[esi+4]
@@: lodsd
add eax,[esi-8]
stosd
loop @b
invoke wsprintf,addr buffer,addr format,eax
add esp,4*3
invoke MessageBox,0,addr buffer,addr caption,MB_OK
invoke ExitProcess,NULL
end startou como esteN equ 9
i = 1
k = 1
rept (N-1)
j = i + k
i = k
k = j
endm
.data
buffer db 50 dup(?)
format db "%u",0
caption db "Fibonacci",0
.code
start: invoke wsprintf,addr buffer,addr format,k
add esp,4*3
invoke MessageBox,0,addr buffer,addr caption,MB_OK
invoke ExitProcess,NULL
end start
Binet's formula (A fórmula de Binet)
(http://e-maxx.ru/tex2png/cache/1094df5457848414456a232b8e0e0254.png)
N equ 12
.data
buffer db 50 dup(?)
format db "%u",0
caption db "Fibonacci",0
const0_5 dd 0.5
k dd ?
inverse_square_root_from_five dd 0.44721359549995793928183473374626;=1/sqrt(5)
square_root_from_five dd 2.2360679774997896964091736687313;=sqrt(5)
.code
start: fninit
fld1 ;st=1
fadd square_root_from_five ;st=1+2.23=3.23
fmul const0_5 ;st=3.23/2=1.618
fld st ;st(1)=st
mov ecx,N
@@: fmul st,st(1) ;st=(1.62)^N
loop @b
fmul inverse_square_root_from_five ;st=((1.62)^N)/sqrt(5)
fistp k
invoke wsprintf,addr buffer,addr format,k
add esp,4*3
invoke MessageBox,0,addr buffer,addr caption,MB_OK
invoke ExitProcess,NULL
end startBinet's formula and fast exponentiation (A fórmula de Binet e exponenciação rápida)N equ 26
.data
buffer db 50 dup(?)
format db "%u",0
caption db "Fibonacci",0
const0_5 dd 0.5
k dd ?
inverse_square_root_from_five dd 0.44721359549995793928183473374626;=1/sqrt(5)
x dd 1.6180339887498948482045868343656;=(1+sqrt(5))/2
.code
start: fninit
fld inverse_square_root_from_five ;st=0.44721359549995793928183473374626
fld x ;st=1.6180339887498948482045868343656
mov ecx,N+1 ;st=1.618 st(1)=0.44721
@@: test ecx,1
jz a1
fmul st(1),st
a1: fmul st,st
shr ecx,1
jnz @b
fstp st
fistp k ;k=int(((1.62)^N)/sqrt(5))
invoke wsprintf,addr buffer,addr format,k
add esp,4*3
invoke MessageBox,0,addr buffer,addr caption,MB_OK
invoke ExitProcess,NULL
end start
I think into russian language man mean "manchini" and woman mean "genchini" phonetically way. Correct me if I'm wrong.
Manchini (Мистер) Mikl__, you're done elegant solutions. Congratulations.
To me author post is learning assembly language, that's why I don't post code, I only tried to show possible corrections about what I think that he was thinking while coding. My fear is about copy and paste code, I think author post can be doing a homework, I hope you understand me.
Fibonacci sequence it's a nice start. The base is just to count rabbits reproduction but after persons see that can be used to count tree nodes. The Nature is fantastic. We still need a way to count how much years old a tree have. The only solution that I know is cut the tree at base and count how many internall circles (spring) lived that tree.
mineiro,
мужчина = homem, женщина = mulher, господин = cavalheiro, госпожа = senhora (http://www.kolobok.us/smiles/standart/don-t_mention.gif)
any professor likes the student that not only correctly fulfill its mission, but also to know about the subject little more than him ask in the university (http://www.kolobok.us/smiles/standart/yes4.gif)
I appreciate all the help. The code Mikl_ provided is definitely more advanced than I am ready for. However, I am trying to understand it.
A windowed example.