Sheng Jiang 蒋晟

;=====================================================================

; lab4.asm – Example function call to get the 20th Fibonacci number

;; Author: Sheng_Jiang

; Course: COSC 2425

; Date: 6/13/05;=====================================================================

.386

.MODEL flat, stdcall

option casemap:none

include windows.inc ; always first

include macros.asm ; MASM support macros

; —————————————————————–

; include files that have MASM format prototypes for function calls

; —————————————————————–

include masm32.inc

include gdi32.inc

include user32.inc

include kernel32.inc

; ————————————————

; Library files that have definitions for function

; exports and tested reliable prebuilt code.

; ————————————————

includelib masm32.lib

includelib gdi32.lib

includelib user32.lib

includelib kernel32.lib

;costants

cr equ 0dh

lf equ 0ah

.Data

.STACK 4096h ;RECURSION need large stacks

.CODE

;Function Fibonacci returns n’th Fibonacci number

;It uses RECURSION

;__stdcall unsigned int f(int x)

;{

; return (x<2) ? 1 : f(x-1) + f(x-2);

;}

;usage:

;push SomethingToAllocateTheReturnValue

;push Parameter;

;call Fibonacci

;stack changes during function call:12

Fibonacci PROC

push ebp

mov ebp , esp

push ecx ; this register is used to calculate the parameters of the function calls

push esi ; sum goes here

FibonacciFunctionBegin:

mov ecx,[ebp+8] ;ecx=param1 = esp/*old*/+4/*new esp*/+4/*pushed ebp*/

cmp ecx,2 ;ecx<2 ?

jge FibonacciRecursion ;return f(x-1) + f(x-2);

mov esi,1 ;otherwise return 1

jmp FibonacciCleanup ;exit function

FibonacciRecursion:

dec ecx ;calculate f(x-1)

push ecx ;allocate the returnValue

push ecx ;ecx=x-1

call Fibonacci

pop esi

dec ecx ;calculate f(x-2)

push ecx ;allocate the returnValue

push ecx ;ecx=x-2

call Fibonacci

pop ecx

add esi,ecx

FibonacciCleanup:

mov dword ptr [ebp+12],esi; //set return values

pop esi

pop ecx

mov esp,ebp

pop ebp

ret 4

Fibonacci ENDP

;int main(int argc, char* argv[])

;{

; printf("the 20th Fibonacci number is:rn";

; return 0;

;}

main PROC

int 3

push ecx ;allocate the return value

push 13 ;

call Fibonacci

print chr$("the 20th Fibonacci number is:",cr,lf)

pop ecx

print str$(ecx);

print chr$(cr,lf)

exit

main ENDP

END main