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Assembly programming Fibonacci Number

I want to write an assembly program to generate Fibonnaci numbers. Following is the code, but it does not work.
Can anybody give me a hand

Masud

.386
.model flat
include cs266.inc
.code
      main:
            PUSH 8
            call fib
            jmp exit1
      exit1:
            putint eax
            ret

      fib:
            PUSH EBP
            MOV EBP, ESP
            MOV EBX, [EBP+8]      ; N
            CMP EBX, 0
            JNE notzero
            MOV EAX,1
            JMP exit
            notzero:
                  CMP EBX,1
                  Jne else
                  MOV EAX,1
                  JMP exit
                  else:
                        DEC EBX            ; N-1
                        PUSH EBX
                        CALL fib      ; fib(N-1)
                        MOV EDX, EAX       ; EDX contains fib(N-1)
                        ;PUSH EDX
                        DEC Edx            ; N-2
                        push ebx
                        CALL fib      ; fib(N-2)
                        ;POP EDX
                        ADD EAX, EDX      ; fib(n-1) + fib (n-2)
                  exit:
                        pop ebp
                        ret 4
      ret
end

ozo

DEC Edx ; N-2
shouldn't this be EBX?

doraiswamy

else: ; here BX has N
DEC EBX ; N-1
PUSH EBX ; store it
CALL fib ; fib(N-1) is returned in EAX
POP EBX
DEC EBX ; n-2
PUSH EAX ; store fib(n-1)
CALL fib ; fib(N-2)
POP EDX ; get back fib(n-1)
ADD EAX, EDX ; fib(n-1) + fib (n-2)
exit:

hclgroup

2 examples I found on the web

http://www.beroset.com/asm/fibo-masm.asm
http://www.beroset.com/asm/fibo.asm

maybe you could get some ideas from there

HasanChowdhury

ASKER

Following the update version, but it still does not work

.386
.model flat
include cs266.inc
.code
main:
      PUSH 8
      call fib
      putint eax
      jmp exit1
      exit1:
            putint eax
            ret
      fib proc
            PUSH EBP
            MOV EBP, ESP
            MOV EBX, [EBP+8]      ; N
            CMP EBX, 0
            JNE notzero
            MOV EAX,1
            JMP exit
            notzero:
                  CMP EBX,1
                  Jne else
                  MOV EAX,1
                  JMP exit
                  else:
                        DEC EBX ; N-1
                        PUSH EBX ; store it
                        CALL fib ; fib(N-1) is returned in EAX
                        MOV EDX, EAX      ; store fib(N-1) to edx
                        PUSH EDX      ; save edx
                        POP EBX
                        DEC EBX       ; n-2
                        PUSH EBX       ; store fib(n-1)
                        CALL fib       ; fib(N-2), fib(n-2) in EAX
                        POP EDX      ; get back fib(n-1)
                        ADD EAX, EDX ; fib(n-1) + fib (n-2)
                        putint eax
                        exit:
                              pop ebp
                              ret 4
      endp
end

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ozo

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