! This programs checks if a number n>1 is prime
! it checks for divisors from 2 to n-1, but does not terminate if n=1

_EXIT	= 1
_WRITE	= 4
_STDOUT	= 1
.SECT .TEXT
start:
	MOV  BX,37 ! hardcoded number to check
	CALL check_prime

    PUSH 2
    PUSH _EXIT
    SYS

! n is loaded from BX
check_prime:
    MOV CX,2 ! number to start at for primality check
l:  CMP CX,BX
    JE end_is_prime ! if CX=BX, exit, n is prime

    ! operate division (DX/CX) <=> (num/current)
    XOR DX,DX ! will store remainder
    MOV AX,BX
    DIV CX

    CMP DX,0 ! check if CX divides BX
    JE end_is_not_prime
    INC CX ! continue loop
    JMP l

end_is_prime:
    PUSH 6
    PUSH is_prime
    PUSH _STDOUT
    PUSH _WRITE
    SYS

    SUB SP,8

    PUSH 0
    PUSH _EXIT
    SYS

end_is_not_prime:
    PUSH 10
    PUSH not_prime
    PUSH _STDOUT
    PUSH _WRITE
    SYS

    SUB SP,8

    PUSH 1
    PUSH _EXIT
    SYS



.SECT .DATA
is_prime:
.ASCII	"prime\n"
not_prime:
.ASCII	"not prime\n"

.SECT .BSS