7.8: Example Program, Sum of Squares

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The following is a complete example program to find the sum of squares from 1 to n. For example, the sum of squares for 10 is as follows:

\[1^2 + 2^2 + \cdots + 102 = 385\nonumber\]

This example main initializes the n value to 10 to match the above example.

;  Simple example program to compute the
;  sum of squares from 1 to n.
; **********************************************
;  Data declarations

section .data

; -----
;  Define constants

SUCCESS         equ     0         ; Successful operation
SYS_exit        equ     60        ; call code for terminate

;  Define Data.

n               dd      10     
sumOfSquares    dq      0

; *******************************************************

section     .text 
global _start 
_start:

; -----
;  Compute sum of squares from 1 to n (inclusive).

; Approach:
;   for (i=1; i<=n; i++)
;       sumOfSquares += i^2;

    mov    rbx, 1                            ; i
    mov    ecx, dword [n]
sumLoop:
    mov    rax, rbx                          ; get i
    mu1    rax                               ; i^2
    add    qword [sumOfSquares], rax 
    inc    rbx
    loop   sumLoop
    
; -----
;  Done, terminate program.

last:
    mov    rax, SYS_exit                     ; call code for exit
    mov    rdi, SUCCESS syscall              ; exit with success

The debugger can be used to examine the results and verify correct execution of the program.