create_tree.asm

This source code is used for make infix expression from prefix expression by using assembly and C la

%include "asm_header.h" ; get the same maccro and define 

; get_node function return the new node in eax register
; node->data = [eax] data is byte
; node->leftChild = [eax+4]
; node->rightChild = [eax+8]
extern get_node 

global create_tree 

segment .data
	number_of_stack_element dw 0 ; this is keep the how many element in stack

segment .text
	

create_tree:
	
;This function make a tree
; call get_node function from c module which is get new node and push it eax
;EAX : use for keeping node
;EBX : use for poping element from stack it keep this element
;EDX : use for temporary for setting parameter top of tree
;ESI : use for keeping string parameter
;EDI : use for keep the lenght of string 
;BL  : use for keep byte in [eax] register
;Function parameter are first top pointer of tree secand string in prefix notation third is lenght of string
;First time stack is like this
;   |lenght of string |
;   |-----------------| 
;   |string prefix    |
;   |-----------------| 
;   |top ptr of tree  |
;   |-----------------|
;   |Return address   |
;   |-----------------|
;   |lEBP , ESP       |
;   |-----------------|
; psueodocode :
; 1 get the parameter esi is string edi is lenght of string
; 2 dec edi becaouse array is begin 0
; 3 while edi is 0
; 4 get the char reverse order in esi
; 5 if it is operand or stack have less than 2 element 
; 6 	go to 12
; 7 else it is operator and stack have more than 2 element
; 8 	pop first element from stack to ebx
; 9 	set first element to left child
; 10	 pop secand element from stack to ebx
; 11 	set ebx to right child
; 12  push ebx to stack
; 13 jmp 3
; 14 leave
; 15 ret

	;set up the ebp and esp register.Crate tree have not got any local variable so first integer is 0
 	enter 0,0
	pusha			; save all GP registers and the flags
	;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
	;INITILIZE the program get the program argument and set the string lengt show last element in string
	;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
	mov esi , secand_param ; get the evaluation string from parameter
	mov edi , third_param ; get the evaluation string length from parameter
	dec edi
	;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
	;END INITILIZE
	;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

make_node:
	cmp edi , 0 		; compare edi is equal zero 
	jl finish 		; if it is less than zero no new char so finish the program
	push dword[ esi + edi ] ; get the char which indice is edi and push it for get_node function
	dec edi 		; decrease edi 
	call get_node 		;get the char and make tree node
	add esp , 4		; add esp 4 for eraseing char
	
understand_only_or_setchild_than_push:
	cmp byte data , '0' 	; compare it '0'
	jge push_node 		; if it is greater than 0 it means this is operand
	cmp word[number_of_stack_element] , 2 ; compare number of stack with2
	jl push_node		;if it is less than it.No get node from stack only push it to stack
	
;element is operand and stack have more than two element so
; set left and right child this operand and push it	
set_node_child: 
	pop ebx 		;get the first element from stak
	dec word[number_of_stack_element] ;after getting element stack element number decrease
	mov left_child , ebx 	;set it to left child
	pop ebx			;pop the secand element 
	dec word[number_of_stack_element] ;after getting element stack element number decrease
	mov right_child , ebx 	;set it to right child
	
;push the new node to stack 
push_node:
	push dword eax ; push it to stack
	inc word[number_of_stack_element] ;after pushing element stack element number increase
	
	jmp make_node ;jump make_node
	
finish: 
	mov edx , first_param ;parameter call by referans so set it
	mov [edx] , eax		;eax is the top of the stack
	
	leave		; clean the stack and set the ebp and esp
	ret		; return to system startup routines

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;END OF CREATE_TREE FUNCTION
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