Question

In assembly language, reverse an array of integers:

# The array will be stored in memory
# The location of arr[0] is SP
# The location of arr[1] is SP+1
# The location of arr[2] is SP+2
# ... and so on

# The size of the array N will be stored in SP-1

# The SP register may be initialized to any value
2: 1024; # Initialize the SP register to 1024 (start of the array)
# ALL other non-constant registers will be initialized to 0
# regardless of any initializers you use.

[1023]: 8; # N = 8 - the array has 8 elements

[1024]: 1; # arr[0] = 1
[1025]: -2; # arr[1] = -2
[1026]: 8; # arr[2] = 8
[1027]: 12; # arr[3] = 12
[1028]: -5; # arr[4] = -5
[1029]: 0; # arr[5] = 0
[1030]: 5; # arr[6] = 5
[1031]: 3; # arr[7] = 3

The goal is to get something like this:

# Goal:
#
# [1024]: 3;
# [1025]: 5;
# [1026]: 0;
# [1027]: -5;
# [1028]: 12;
# [1029]: 8;
# [1030]: -2;
# [1031]: 1;
#

Answer 1

1. Reverse an array 
.data
        array DWORD 1, -2, 8, 12, -5, 0, 5, 3   ;array to be reversed
.code

main proc
    mov esi, 0
        mov edi, 0
        mov eax, 0
        mov ebx, 0

        mov esi, OFFSET array                                   ;move first element address to esi
        mov edi, OFFSET array + SIZEOF array - TYPE array  
                                                 ;move last element address to edi
        
        mov ecx, LENGTHOF array / 2               ;sets the counter in the reverseLoop

reverseLoop:
        mov eax, [esi]    ;move the element in esi to eax
        mov ebx, [edi]    ;move the element in edi to ebx

        xchg eax, ebx     ;exchange the two elements

        mov [esi], eax  ;move the element in eax, to the address in esi
        mov [edi], ebx  ;move the element in ebx, to the address in edi

        add esi, TYPE array ;increase esi to take the next element in the array (from the left)
        sub edi, TYPE array ;decrease edi to take the next element in the array (from the right)

        loop reverseLoop

        invoke ExitProcess,0
main endp
end main

2. Assign to the new location : 1024

.data   
A DW 1, -2, 8, 12, -5, 0, 5, 3 ; Array named 'A'
mov N, 8                ; variable N = array size

I   .BLOCK   1         ;   var i; // Numeric  
A   .BLOCK   N         ;   var a = new array(8); // Numeric  

LOADIMM   REGA,   0      ;  
TORE   REGA,   I      ;   i = 0;  
LOOP   LOAD   REGA,   I      ;   while (i < N)  
LOADIMM   REGB,   1024      ; Base value of B = 1024   
COMPARE   REGA,   REGB      ;  
BRANCH   GE,   ENDLP      ;  
LOADIMM   REGA,   1      ;   Register A assigned the base address of array a  
LOAD   REGB,   I+1024      ;   Register B assigned the value of subscript i+1024  
ADD   REGC,   REGA,   REGB   ;   Register C assigned the address of a[i+1024]  
LOADIND REGA, REGB
STORE REGA, X           ;    getting the value of a[i] and store into X an integer
LOADIMM   REGD, X          ;   Register D assigned the constant = array value  
STOREIND REGD,   REGC      ;   a[i+1024] = X;  
LOAD   REGA,   I      ;  
LOADIMM   REGB,   1      ;  
ADD   REGC,   REGA,   REGB   ;  
STORE   REGC,   I      ;   i = i + 1;  
JUMP   LOOP         ;   }  
ENDLP   HALT            ;  

====

ARRAY D has stored all the required values.