%include "CONSTANTS.h"

section .data
    prompt: db `Enter a value for n \n`,0
    inputFmt: db `%d`,0
    endl: db `\n`,0
    fmtString: db `%d! = %20d\n`,0
    debugString: db `%d is the number\n`,0

section .bss
    
section .text

global main
main:
    ;mov rdi, format1
    ;mov rsi, -1
    ;call CallPrintf 

    ; cout << "Enter a number"
    mov rdi, prompt
    call CallPrintf

    ; cin >> n
    mov rdi, inputFmt
    call CallScanf
    mov r14, rsi;

    mov rdi, debugString
    call CallPrintf

   ; r12 will be i
   ; r13 will be fact
   ; r14 will be n

   ; save the input value from rsi to r14

   ; if n == 0 or n == 1
   cmp r14, 0;
   je factIs1
   cmp r14, 1
   je factIs1
   ; else
   ;   fact 1;
       mov r13, 1
   ;   i = 2;
       mov r12, 2
topOfLoop:
   ;   while i <= n
   cmp r12, r14
   jg outOfLoop;
   ;     fact *= i
   imul r13, r12

   ;     print  i! = fact
   mov rdi, fmtString
   mov rsi, r12
   mov rdx, r13
   ;   I had forgotten to put the call to printf in  during class.
   call CallPrintf

   ;     i++
   inc r12
   jmp topOfLoop

factIs1:
   ;   cout n! = 1
   mov rdi, fmtString
   mov rsi, r14
   mov rdx, 1
   call CallPrintf

outOfLoop:

   jmp Exit