delay in assembly 8086

I am trying to delay my movement in a game I'm creating. My problem is that every time that I use the int 1Ah the movement suddenly becomes "rusty" (not moving in a constant line) while my delay procedure where I use "nop" makes a solid movement and not rusty. My teacher says that I can't use a loop with "nop" and I don't know how to do a delay that uses 1Ah and looks fine (not rusty) I'm using graphics mode and assembly x86 Thanks. It works just fine, but my teacher probably won't like it for some reason.

my delay proc:

proc delay   

delRep:
    push    cx  
    mov     cx, 0FFFFH 
delDec:
    dec     cx 
    jnz     delDec
    pop     cx
    dec     cx
    jnz     delRep
    ret
endp delay