Question

Assembly MASM x86

Write a complete program that sorts dword unsigned integer array in descending order.

Assume that the user doesn’t enter more than 40 integers.

You MUST use the template and follow all the directions there.

You can’t add any more procedures to the template.

The procedures can’t use any global variables (variables that are inside .data segment).

The caller of any procedures sends its argument through the stack.

Inside any procedures, if you need to use a register, you have to preserve its original value. You can't use uses, pushad operators.

The callee is in charge of cleaning the stack.

Your lines must not exceed 80 columns

Sample run:

Enter up to 40 unsigned dword integers. To end the array, enter 0.

After each element press enter:

1

4

3

8

99

76

34

5

2

17

0

Initial array:

1 4 3 8 99 76 34 5 2 17

Array sorted in descending order:

99 76 34 17 8 5 4 3 2 1

Press any key to continue . . .

//////////////////////////////////////////////////////////////////////////////////////////////////////////

Template :

include irvine32.inc
; ===============================================
.data

array dword 40 dup(?)
string1 byte "Enter up to 40 unsigned dword integers. To end the array, enter 0.",0
string2 byte "After each element press enter:", 0
string3 byte "Initial array:",0
string4 byte "Array sorted in descending order:",0

;=================================================
.code
main proc
; YOU NEED TO CALL ENTER_ELEM, SORT_ARR AND PRINT_ARR PROCEDURES

mov edx, offset string1
call writeString
call crlf
call crlf

mov edx, offset string2
call writeString
call crlf

mov esi, offset array
mov ecx, LENGTHOF array
push esi
mov eax, 0
L1:
call Readdec ; read integer into EAX
mov [esi],eax ; store in array
cmp eax, 0
JE end01
add esi,TYPE array ; next integer
call enter_elem
loop L1

end01:
mov edx, offset string3
call writeString

call print_arr

exit
main endp

; ================================================
; void enter_elem(arr_addr)
;
; Input:
; ARR_ADDRESS THROUGH THE STACK
; Output:
; ARR_LENGTH THROUGH THE STACK
; Operation:
; ?
;
enter_elem proc
push ebp ;set ebp
mov ebp, esp
push eax ; save register
mov esi, [ebp + 12]; pointing to value in array
mov ecx, [ebp+8]
add esi, 4 ; move pointer to next value in array
pop eax
pop ebp

ret 4
enter_elem endp
; ================================================
; void print_arr(arr_addr,arr_len)
;
; Input:
; ?
; Output:
; ?
; Operation:
; ?
;

print_arr proc

push ebp ;set ebp
mov ebp, esp
push eax

L2:
mov eax, DWORD ptr [esi] ;store in new array
call writeDec
add esi, TYPE array ;next integer
mov al,', '
call writeChar ;Displays value in EAX
loop L2
pop eax
pop ebp

ret 4
print_arr endp
       ; ================================================
       ; void sort_arr(arr_addr,arr_len)
       ;
       ; Input:
       ; ?
       ; Output:
       ; ?
       ; Operation:
       ; ?
       ;

   sort_arr proc

       ; FILL YOUR CODE HERE
       ; YOU NEED TO CALL COMPARE_AND_SWAP PROCEDURE

   sort_arr endp

       ; ===============================================
       ; void compare_and_swap(x_addr,y_addr)
       ;
       ; Input:
       ; ?
       ; Output:
       ; ?
       ; Operation:
       ; ?
       ;

   compare_and_swap proc

       ; FILL YOUR CODE HERE
       ; YOU NEED TO CALL SWAP PROCEDURE

   compare_and_swap endp

       ; =================================================
       ; void swap(x_addr,y_addr)
       ;
       ; Input:
       ; ?
       ; Output:
       ; ?
       ; Operation:
       ; SWAP ONLY IF Y > X
       ;

   swap proc

       ; FILL YOUR CODE HERE

swap endp

end main

Answer 1

                                         enter_elem proc
mov eax, 0
    L1:
call    Readdec         ; read integer into EAX
    mov [esi],eax           ; store in array
cmp eax, 0
JE end01
    push ebp          
mov ebp, esp
push eax          ; save register
push esi          ; save register
mov esi, [ebp+12]  ; pointing to value in array
add esi,4

        pop esi pop eax pop ebp add esi, 4 ; move pointer to next value in array

    end01: 

   ret 4
   enter_elem endp