; Find the difference between (1+2+3+...+100)^2 and (1^2+2^2+3^2+...+100^2)
; I used another math trick here:
; The sum up to a number can be found using Gauss' Trick:
; 1 + 2 + 3 + ... + 10 -> (1+9) + (2+8) + (3+7) + (4+6) + 10 + 5 -> 5*10 +5
; In general : (n/2)(n+1)

extern printf
SECTION .data
flag:   db  "%d",10,0           ; "%d\n\0"

SECTION .text
    global main    
    global is_divisible

main:
        push rbp                ; set up stack
        mov rbp, rsp

        ; first square of sum (1+2+...100)^2
        mov rax, 50             ; sum = n/2 
        mov rcx, 101            ; * (n + 1)
        mul rcx
        mul rax                 ; square it
        push rax                ; save it
        
        ; now sum the squares (1^2+2^2 ...) no short cut this time
        xor r11, r11            ; This will store the sum, rcx will b n, 
                                ; rax is just used to multiply
        mov rcx, 0              ; n = 0, we add one first

.loop   inc rcx                 ; see? told you :)
        mov rax, rcx            ; move into multiply register
        mul rax                 ; multiply by itself
        add r11, rax            ; add to the sum
        cmp rcx, 100            
        jne .loop

        pop rax                 ; sum of the squares is on the stack
        sub rax, r11            ; take the difference, rax - r11
                                ; square of the sum is bigger
.print  mov rdi, flag           ; arg 1 (format)
        mov rsi, rax            ; arg 2 (value)
        mov rax, 0		; no xmm registers
        call printf wrt ..plt
        pop rbp

        mov rax, 0
        ret