calculate.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 

global calculate

segment .bss
	quardword resq 1  ; this is keep quard word for pushing float stack

segment .text

calculate:
;This function is use for walk on tree by using postorder recursively and calculate the result
;Get to parameters one is pointer of top of tree 
;return result in float format
;EAX : use for keeping node
;EBX : use for keeping the data of eax than munis 30h for finding integer value of char
;EDX : use for temporary for keeping eax child and push it to stack
;Stack frame for one calling recursive function

;   |top ptr of tree  |
;   |-----------------|
;   |Return address   |
;   |-----------------|
;   | EBP             |
;   |-----------------| 
;   |top ptr of tree  | ESP
;pseudocode
; 1 reverse 4 byte for local variable which is child of node
; 2 get the parameter eax node 
; 3 if node in eax is null jump the finish
; 4 push the left child of node in eax and string
; 5 call inorder for left child
; 6 get the node in eax
; 7 put the right child 
; 8 call inorder for right child
; 9 if node in eax is null jump the finish
; 10 else if it is operator put to it float stack
; 11 else undertand it is +,-,* or / than call it's function
;	11.1 apply operator to st0 and st1
; 12 leave and ret


	enter 4,0 ;reverse 4 byte for local varaible which is child of node
	
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	;INITILIZE the program get the program argument which is only top of tree
	;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
	mov eax , first_param ; get the top pointer of tree
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	;END INITILIZE
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start_calculate:	
	compare_null_jmp_je_finish eax	; if eax (node) is null jmp the finish
	
	move_than_push_it edx , dword left_child ;if it is node push it's left child 
	
	call calculate ; call calculate for left child
	
	mov eax , first_param ; get the first parameter from the stack
	
	add esp , 4 ; move esp 4 byte for clear the local variable
	
	compare_null_jmp_je_finish eax	; if eax (node) is null jmp the finish
	
	move_than_push_it edx , dword right_child ; if it is node push it's right child
	
	call calculate ; call calculate for right child
	
	mov eax , first_param ; get the first parameter from stack

	compare_null_jmp_je_finish eax	; if eax (node) is null jmp the finish
	
	switch_case:
	cmp byte[eax] , '0' ; compare it is operator or operand
	jge add_float_stack ; if it is operand jump the add_float_stack
	cmp byte[eax] , '+' ;compare it is +
	je float_add	    ;if it is + than jump float add
	cmp byte[eax] , '-' ;compare it is a -
	je float_minus	    ;if it is - than jump float minus
	cmp byte[eax] , '*' ; compare it is a *
	je float_mul	    ;if it is * jump float mul	
	cmp byte[eax] , '/' ;compare it is a /
	je float_div	    ;if it is / jump the float_div	
	
add_float_stack:
	mov ebx , dword data ;copy the data to ebx
	sub ebx , 30h	     ;munis 30h from char to make it integer
	mov dword [quardword], ebx ;put it the variable which is reserve for quard word
	fild  qword [quardword]	;push the quardword to float stack
	jmp finish	;jump the finish
	
float_add:
	faddp st1	;pop the sto and st1 than add it and push the result to stack
	jmp finish	; jump the finish
	
float_minus:
	fsubp st1	;pop the sto and st1 than munis it and push the result to stack
	jmp finish	; jump the finish

float_mul:
	fmulp st1	;pop the sto and st1 than multiply it and push the result to stack
	jmp finish	; jump the finish
	
float_div:
	fdivp st1	;pop the sto and st1 than divide it and push the result to stack
	jmp finish	; jump the finish

finish: 
	leave		; clean the stack and set the ebp and esp
	ret		; return to system startup routines

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;END OF CALCULATE FUNCTION
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