.define .inn
.text

	! #bytes in cx
	! bit # in ax
.inn:
	xor     dx,dx
	mov     bx,#8
	div     bx
	mov     bx,sp
	add	bx,#2
	add     bx,ax
	cmp     ax,cx
	jae     1f
	movb	al,(bx)
	mov	bx,dx
	testb   al,bits(bx)
	jz      1f
	mov	ax,#1
	jmp	2f
1:
	xor	ax,ax
2:
	pop	bx
	add     sp,cx
	! ax is result
	jmp     (bx)

	.data
bits:
	.data1 1,2,4,8,16,32,64,128